Research
Publications

Beef Cattle Management and Health

• Feedlot Performance of Steers and Bulls Actively Immunized Against Gonadotropin-Releasing Hormone
  Adams, T.E., and B.M. Adam
  
  
• Reproductive function and feedlot performance of beef bulls, steers or bulls actively immunized against GnRH: effect of Synovex S. Proc.
  Adams, T.E., C.A. Daley, B.M. Adams, and H. Sakurai
  
  
• Testis function and feedlot performance of bulls actively immunized against gonadotropin-releasing hormone: effect of implants containing progesterone and estradiol benzoate
  Thomas E.Adams, C.A. Daley, B.M. Adams, and H. Sakurai
  
  
• Development and application of an electronic recording system to measure grazing and rumination in range cattle
  Alexander, G.L.
  
  
• Electronic recording of grazing and rumination behavior in range cattle
  Alexander, G.L., and J.G. Morris
  
  
• Effect of penicillin or penicillin and dexamethasone in cattle with infectious bovine keratoconjunctivitis
  Allen, L.J., L.W. George, and N. Willits
  
  
• Assessing the risk of surface water contamination of Cryptosporidium parvum from beef cattle production: Implications for land use restrictions
  Rob E. Atwill
  
  
• Abomasal interstitial fluid-to-blood concentration gradient of pepsinogen in calves with type-1 and type-2 ostertagiosis
  Baker, D.G., M.L. Bruss, and L.J. Gershwin
  
  
• Seasonal patterns of total and Ostertagia-specific IgE in grazing cattle
  Baker, D.G., and L.J. Gershwin
  
  
• Immunoglobulin E and Type I hypersensitivity in bovine ostertagiosis
  Baker, D.G., and L.J. Gershwin
  
  
• Inverse relationship between IgE and worm burdens in cattle infected with Ostertagia ostertagi
  Baker, D.G., and L.J. Gershwin
  
  
• Cellular and Chemical Mediators of Type 1 Hypersensitivity in Calves Infected with Ostertagia ostertagi: Histamine, Prostaglandin D2, Prostaglandin E2, and Leukotriene C4
  Baker, D.G., L.J. Gershwin, S.N. Giri, and C. Li
  
  
• Cellular and Chemical Mediators of Type 1 Hypersensitivity in Calves Infected with Ostertagia ostertagi: Mast Cells and Eosinophils
  Baker, D.G., L.J. Gershwin, and D.M. Hyde
  
  
• Celiac trunk cannulation for obtaining abomasal lymph from cattle
  Baker, D.G., L.J. Gershwin, and T.G. Snider, III
  
  
• Abomasal lymphatic lymphocyte subpopulations in cattle infected with Ostertagia ostertagi and Cooperia sp
  Baker, D.G., J.L. Stott, and L.J. Gershwin
  
  
• Protection of livestock against internal parasites by management methods
  Baker, N.F.
  
  
• Ivermectin and other controls for internal parasites of cattle
  Baker, N.F.
  
  
• Seasonal occurrence of infective nematode larvae in California Sierra foothill pastures grazed by cattle
  Baker, N.F., and R.A. Fisk

• Seasonal occurrence of infective nematode larvae on irrigated pasture grazed by cattle in California
  Baker, N.F., R.A. Fisk, R.B. Bushnell, and M.N. Oliver
  
  
• Determining forage diet quality by analyzing fecal matter with near infrared spectroscopy
  Barry, S.
  
  
• Estimation of the effect of decreasing public land allotment on beef production in Northern California
  Beckett, J.L., J.W. Oltjen, D.J. Drake, R.E. Delmas, H.A. George-McCann, G.A. Nader, and L.C. Forero
  
  
• Fertilization in ungulates
  Berger, T.
  
  
• Proportion of males with lower fertility spermatozoa estimated from heterospermic insemination
  Berger, T.
  
  
• The effect of pelvic area on calving difficulty in beef heifers
  Connor, J.M., S.L. Berry, C.B. Wilson, and C. Daley

• Results from breeding yearling heifers to bulls of three breeds: 1. Dystocia and calf production measures
  Connor, J.M., C.B. Wilson, J.L. Hull, S.L. Berry, and C.A. Daley
  
  
• First calf heifer management
  Connor, J.M.
  
  
• A three year look at stocking density and rainfall patterns on gain of stocker cattle
  Daley, C
  
  
• Synchronization of estrus with MGA (Melengestrol Acetate) and Lutalyse in yearling heifers
  Daley, C
  
  
• Development of a vaccine to prevent pregnancy/cyclicity in heifer calves
  Daley, C.A., and T.E. Adams

• Management of the Research Herds at the Sierra Field Station
  Delmas, R.E.
  
  
• Ralgro for replacement heifers
  Delmas, R.E.
  
  
• Prevalence of Cryptosporidia parvum, Giardia duodenalis, and Campylobacter jejuni in beef calves and impacts on preweaning gain and weaning weight
  Drake, D.J., E.R. Atwill, J.M. Connor, and D. Jones
  
  
• Range supplementation strategies for steers grazing the Sierra foothills of California
  Dunbar, J., J. Oltjen, M. Sween, M. Connor, H. Johnson, and C. Wilson
  
  
• Bypass protein for growing range calves
  Dunbar, J.R., J.M. Connor, C.B. Wilson, C.A. Raguse, T.R. Famula, C.A. Daley, and M.R. George
  
  
• Utilization of by-pass protein in liquid supplements
  Dunbar, J.R., C.A. Daley, J.M. Connor, C.B. Wilson, C.A. Raguse, T.R. Famula, and M.R. George

• Supplements evaluated for wintering range calves
  Dunbar, J.R., C.A. Daley, J.M. Connor, C.B. Wilson, C.A. Raguse, T.R. Famula, and M.R. George
  
  
• Cupric-oxide needles effective as oral copper supplement in cattle
  Dunbar, J.R., J.G. Morris, B.B. Norman, A.J. Jenkins, C.B. Wilson, and J.M. Connor
  
  
• Selenium pellets for cattle
  Dunbar, J.R., B.B. Norman, and W.H. Johnson
  
  
• Range supplementation stategies for steers grazing the Sierra foothills of California
  Dunbar, J., J. Oltjen, M. Sween, M. Connor, H. Johnson, and C. Wilson
  
  
• Range cow nutrition
  Dunbar, J.R., C.B. Wilson, and J.M. Connor
  
  
• Clinical infectious bovine keratoconjunctivitis
  George, L.W.

• Treatment methods for pinkeye in cattle
  George, L.W.
  
  
• Managing pinkeye in beef cattle
  George, L.W.
  
  
• Treatment of Moraxella bovis infections in calves using a long-acting oxytetracycline formulation
  George, L.W., and J.A. Smith
  
  
• Beef Heifers to be Bred as Yearlings
  Hull, J.L.
  
  
• Livestock for irrigated pasture
  Hull, J.L.
  
  
• Managing beef heifers for early breeding
  Hull, J.L.

• Protein-energy supplements for beef heifers
  Hull, J.L., R.E. Delmas, and E.J. DePeters
  
  
• Straw: low-cost feed but not least cost
  Hull, J.L., and J.R. Dunbar
  
  
• Rice or barley straw for pregnant beef cows
  Hull, J.L., W.N. Garrett, and J.R. Dunbar
  
  
• Irrigated Pasture for Beef Heifers to be Bred as Yearlings
  Hull, J.L., and C.A. Raguse
  
  
• Utilizing irrigated pasture for beef heifers to be bred as yearlings
  Hull, J.L., and C.A. Raguse
  
  
• Rumensin supplements for replacement heifers on irrigated pasture
  Hull, J.L., C.A. Raguse, and R.E. Delmas

• Supplementation of dry annual range by irrigated pasture
  Hull, J.L., C.A. Raguse, and J.P. Guild
  
  
• Feedlot animal waste compared with cottonseed meal as a supplement for pregnant range cows
  Hull, J.L., C.A. Raguse, J.G. Morris, and R. Delmas
  
  
• Hepatic and plasma concentration of carotene and vitamin A in range cows
  Iglesias, T., and J.G. Morris
  
  
• Body condition scoring beef cows
  Ingram, R., J. Dunbar, B. Willoughby, C. Wilson, and M. Connor
  
  
• Selenium improves weight gain of beef calves
  Johnson, W.H., B.B. Norman, and J.R. Dunbar
  
  
• The Nematode Heterotylenchus autumnalis and face fly Musca autumnalis: a field study in Northern California
  Kaya, H.K., and R.D. Moon

• Influence of the nematode Heterotylenchus autumnalis on the behavior of face fly Musca autumnalis
  Kaya, H.K., R.D. Moon, and P.L. Witt
  
  
• Efficacy of lasalocid and decoquinate in controlling coccidiosis in beef calves raised in foothill range
  Letshwenyo, M.
  
  
• Evaluation of Cooper's ear tag for fly control on cattle
  Loomis, E.C.
  
  
• Bovine coccidiosis
  Maas, J.G.
  
  
• Assessment of sodium requirements of grazing beef cattle: A review
  Morris, J.G.
  
  
• Supplementation of range cattle
  Morris, J.G.

• Supplementary feeding breeding cows on range. Is it profitable?
  Morris, J.G.
  
  
• Energy balance of grazing beef cows
  Morris, J.G.
  
  
• Evaluation of feeding value and costs of cattle supplements
  Morris, J.G.
  
  
• Range cow management
  Morris, J.G.
  
  
• Improving the Delivery of Supplements to Range cattle
  Morris, J.G., and R.E. Delmas
  
  
• Seasonal variation in the nutritive nature of California range forage for cattle
  Morris, J.G., and R.E. Delmas

• Portable self-feeder for supplementing cattle on range
  Morris, J.G., and R.E. Delmas
  
  
• Effect of Stocking Rate on Liveweight Gains
  Morris, J.G., and J.L. Hull.
  
  
• Pinkeye (Infectious Bovine Keratoconjunctivitis - IBK)
  Norman, B.B.
  
  
• Strategic supplementation of range beef cows: split feeding by body condition and stocking rate
  Oltjen, J.W.
  
  
• Age-related changes in the sexual performance of Hereford bulls
  Price, E.O., and R. Borgwardt
  
  
• The effects of twinning on mother-offspring behavior in range beef cattle
  Price, E.O., C.L. Martinez, and B.L. Coe

• Inability to predict the adult sexual performance of bulls by prepuberal sexual behaviors
  Price, E.O., and S.J.R. Wallach
  
  
• Development of sexual and aggressive behaviors in Hereford bulls
  Price, E.O., and S.J.R. Wallach
  
  
• Beef Calf Production From Irrigated Pasture, Supplements and Winter Annual Range in the Sierra Nevada Foothills
  Raguse, C.A., J.L. Hull, and R.E. Delmas
  
  
• Correlation of steer average daily gain with diet quality and forage phenology in an improved annual grassland
  Raguse, C.A., J.G. Morris, and V.N. Landry
  
  
• Value-based marketing of beef cattle
  Sainz, R.D.
  
  
• Energy expenditure and intake in range beef cattle
  Sanchez, M.D.
  
  
• Energy expenditure and feed intake of beef cattle grazing annual rangeland
  Sanchez, M.D.
  
  
• Generation and characterization of murine monoclonal antibodies specific for bovine immunoglobulin E. Vet. Immunol
  Thatcher, E.F., and L.J. Gershwin

• Effects of stress factors on the estrous cycles of beef heifers
  Wagnon, K.A., W.C. Rollins, P.T. Cupps, and F.D. Carroll
  
  
• Results of breeding yearling heifers to bulls of three breeds; 2. Feedlot and carcass performance
  Wilson, C.B., J.L. Hull, S.L. Berry, C. Daley, and J.M. Connor
  
  
• The effects of multiple selenium rumen pellets in feeder cattle
  Wilson, C.B., D.J. Wilson, B.B. Norman, and J.R. Dunbar
  
  
• The effects of multiple selenium rumen pellets in feeder calves
  Wilson, D.J.
  
  
• Evaluation of multiple reticulorumen selenium pellets as a health risk in growing Hereford steers
  Wilson, D.J., B.B. Norman, D.W. Hird, C.B. Wilson, and M.N. Oliver
  

1992. J. Anim. Sci.70:pp.1691-1698.
Feedlot performance and testicular and pituitary function were assessed in cattle actively immunized against GnRH. Taken together, these data indicate that the GnRH-KLH conjugate is an effective immunogen in steers and bulls, with primary immunization alone as effective as the more conventional multiple-injection regimen.

1992. UC Sierra Foothill Range Field Station Beef and Range Field Day:pp.23-30.
The results of this study indicate that vaccination of bull calves against GnRH suppresses testicular development and function. Such treatment also retards expression of secondary sex characteristics such as change in scrotal circumference and masculinity. Although not measured, sex-linked behavioral characteristics, such as aggressiveness, may also be depressed in immunized bulls.

1993. J. Anim. Sci.71: pp. 811-817.
The effect of implants containing anabolic steroid (Synovex) on testis function, feedlot performance, and carcass traits was evaluated in bulls, steers, and bulls actively immunized against gonadotropin-releasing hormone (GnRH). Immunization, like Synovex, reduced the masculinity of the carcasses of bulls. Taken together, these data indicate that immunization against GnRH may have practical utility as a noninvasive alternative to surgical castration in management of beef cattle. In addition, the residual levels of testosterone secretion in immunized bulls may have anabolic effects that reduce the need for supplementation with exogenous steriod.

1979. Thesis, Univ. of Calif., Davis:p.90.
This study investigates a system that records and transmits information on individual jaw movements of free ranging cattle. The system consists of a jaw movement sensor, a storage-transmitter unit which transmits the information to a receiver and a computer to receive and store the information. The two transmitters gave data that was fairly consistent with that of other studies. Activity times, number of daily chews and chewing rates all fell within reasonable ranges although further adjustments and refinements were required to remove the slight underestimations of grazing and rumination times. There were no extreme variations from day to day, indicating trends in activities are reliable.

1987. UC Sierra Foothill Range Field Station Beef and Range Field Day:pp.33-40.
A system that records and transmits data concerning times of occurrence of individual jaw movements of free ranging cattle is described. Intake of forage is a major factor in determining the level of production from grazing animals. Profitability maydepend to a large part on the grazing animal achieving as high an intake as is possible and so it is important to understand and quantify the factors involved. In this experiment the data are transmitted hourly at a fixed time; records contain the jaw movements for the currently logged hour as well as the previous two hours.

1995. J. Am. Vet. Med. Assoc. 206(8):pp.1200-1203.
To evaluate the efficacy of penicillin or penicillin and dexamethasone for treatment of infectious bovine keratoconjunctivitis, 6-to-8 month old heifers with infectious IBK were randomly treated. On the basis of the findings in this controlled study, we suggest that subconjunctival administration of procaine penicillin G, with or without dexamethasone, does not significantly affect the outcome of naturally developing IBK. Under the conditions of our study, the cost of treating affected cattle subconjunctivally with penicillin or with penicillin/dexamethasone combinations may be unjustified.

1995. Proc., UC Sierra Foothill REC Beef and Range Field Day:pp.15-17.
The critical issue is how would Cryptosporidium parvum from calves gain access to surface waters and end up in drinking water supplies. The essential steps must include calves becoming infected and shedding the oocysts in their feces. These oocysts must then enter a surface water supply and remain infective as they journey downstream to water treatment plants and distribution systems. The scientific evidence supporting the claim that cattle are a significant source of C. parvum for surface water is incomplete and contradictory in some cases. It is premature at this time to claim that cattle production is a leading source of C. parvum in surface water.

1993. Am. J. Vet. Res.54:pp.1294-1298.
Pepsinogen and protein concentrations were determined in blood samples, collected from the left gastroepiploic artery and vein, and in abomasal lymph from 15 steers naturally infected with Ostertagia ostertagi and 4 uninfected steers. High interstitial pepsinogen concentrations may have resulted from increased epithelial permeability or increased pepsinogen production and secrection.

1992. Vet. Parasitology 44: pp.211-221.
Serum samples, collected monthly from January through December 1988 from 10 cows, their calves, and 10 yearling heifers, were used to determine total and Ostertagia-specific IgE levels. In addition, serum pepsinogen concentration, fecal egg counts, and body weights were measured. Total and Ostertagia-specific IgE levels followed similar seasonal patterns, being generally highest in the spring. Breed and/or sire effects on total IgE levels were observed, with cattle from Angus-cross lines having higher levels than cattle of the other breeds tested.

1993a. Vet. Parasitology 46:pp.93-102.
A series of experiments were performed to determine whether immunoglobulin E (IgE) and Type I hypersensitivity reactions might be involved in the immune response of cattle to infection with Ostertagia ostertagi. When calves were lightly infected, serum IgE levels paralleled worm burdens. However, in heavy infections, both serum and lymph IgE levels were inversely related to burdens of O. ostertagi. Increases in mediators, especially histamine and leukotriene (LT) C4 were detected in tissue or lymph, and were associated with cellular changes indicative of hypersensitivity.

1993b. Vet. Parasitology 47: pp. 87-97.
Changes in serum total and Ostertagia-specific IgE levels, and pepsinogen concentrations were evaluated in 28 Holstein calves naturally or experimentally infected with Ostertagia ostertagi. In addition, IgE and pepsinogen concentrations were determined in abomasal lymph. Results showed that (1) lymph IgE responses were inversely correlated with worm burdens, and (2) serum IgE levels were unreliable for predicting worm burdens.

1993. International. J. Parasitology 23: pp. 333-339.
Cellular and chemical mediators of type 1 hypersensitivity in calves infected with Ostertagia ostertagi include: histamine, prostaglandin D2, prostaglandin E2, and leukotriene C4. Levels were determined in 26 Holstein steers before and after natural or experimental infection with Ostertagia ostertagi.

1993. International J. Parasitology 23: pp. 327-332.
Abomasal mucosal mast cell and eosinophil accumulation was morphometrically evaluated in 26 Holstein steers after natural or experimental infection with Ostertagia ostertagi. Results showed that following infection, accumulation of mast cells and eosinophils in abomasal tissue was dependent on infection pattern. Eosinophilia was greater in steers with type 1 ostertagiosis, while mastocytosis was more pronounced in steers with type 2 ostertagiosis.

1991. Am. J. Vet. Res. 52: pp. 1117-1120.
Cannulation of the celiac trunk was surgically performed in 26 Holstein steers. The procedure was successful in 23 (88.5%) of the steers. Twenty-two of the steers were infected either naturally or experimentally the abomasal nematode, Ostertagia ostertagi and/or other gastrointestinal parasites. The remaining 4 steers were not infected. Lymph obtained after surgery was used in various immunologic and biochemical assays. Daily lymph flow rate and total and differential WBC counts were determined after surgery in 4 of the infected and 3 of the noninfected steers. Steers were euthanatized for tissue specimen collection 7 days after surgery. with type 2 ostertagiosis.

1993. Vet. Immunol. Immunopathol. 39: pp. 467-473.
Abomasal lymphatic cannulation was performed on steers naturally or experimentally infected with Ostertagia ostertagi and Cooperia sp. Abomasal lymphatic lymphocyte subpopulations were evaluated using antibodies specific for bovine mononuclear cell surface antigens, followed by flow cytometric analysis. These findings are compatible with reports of worm-specific antibody synthesis in bovine nematodiases.

1980. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 41-43.
It has recently been estimated that losses to the cattle industry as a result of internal parasites exceeds 450 million dollars annually. Such a large loss due to disease could well be prevented if all cattle were to be treated monthly with the anthelmintics presently available. Unfortunately, if this were done, the cost to the livestock industry in dollars for drug purchase and labor of administration would exceed the present loss as the result of disease! Thus, where possible we must utilize management practices which do not interfere with maximal productivity, yet minimize exposure to parasitic infection.

1985. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 1-3.
The reduction of contamination of pastures in California through residual treatment to remove developing worms in the fall, or by single treatment to remove all stages of worms from cattle in summer, will greatly reduce infection rates on pasture in the following winter and spring. Whether or not this single treatment will be adequate to pro tect against performance losses in all instances during winter and spring has not been determined. Where it is possible to utilize such a treatment, this certainly must be considered the cornerstone to a successful control program. Such programs will require modification when cattle are brought in from other states.

1986. Am. J. Vet. Res. 47: pp. 1680-1685.
Worm-free Holstein tracer calves were used to assess the seasonal variation in number and course of development of nematode parasites of cattle on an irrigated pasture located in the California Sierra foothills. The most common genera of nematodes found in the abomasum and small intestine were Ostertagia and Cooperia, respectively. The infective Ostertagia larvae on herbage were most numerous in early spring and lowest in summer months. Arrested development of Ostertagia occurred in mid-to-late spring. Evidence of seasonal hypobiotic development of Os venulosum was found.

1981. Am. J. Vet. Res. 42: pp. 1188-1191.
During the period extending from Dec 1, 1975 to Dec 22, 1976, 3 distinct peaks in the concentration of infective nematode larvae on pasture forage were detected by use of helminth-free tracer calves. Two of these peaks, 1 occurring in the spring and 1 in the fall, consisted mainly of Ostertagia ostertagi and Cooperia sp. It is conclu ded that these 2 peaks can be anticipated annually and constitute unsafe periods for grazing. The 3rd peak was comprised largely of Haemonchus placei and Cooperia sp. It isconcluded that this peak occurred as the result of unusual rainfall and reduced evaporation in August.

1996. Proc., UC Sierra Foothill REC Beef and Range Field Day. pp. 27-30.
A relatively new technique developed by the Department of Range Ecology at Texas A&M University can quickly determine the nutritional status of cattle grazing rangeland or pasture. Cattle manure is analyzed using near infrared reflectance spectroscopy (NIRS). Manure samples have been collected from ranches throughout the Sacramento Valley and Sierra Foothill, etc. and analyzed using the NIRS process. Ref.278\64.14.

1993. Proc., UC Sierra Foothill REC Beef and Range Field Day: pp. 5-10.
A number of experiments on supplementation of steers under annual range conditions at the UCSFREC have demonstrated that supplements may affect growth, but profit per acre may not always improve. If net economic return per acre is to be maximized then animal production must be optimal. Correct management strategy for the different resources and seasons of the year will vary from ranch to ranch and year to year. The effects of supplements on forage intake are complex in grazing cattle where interactions between grazing, supplement intake, forage availability and conditions may modify normal mechanisms that regulate intake.

1996. Animal Reproduction Sci. 42: pp.351-360.
The fertilization process is critical for the preservation of mammalian species. The range in sperm fertilizing potential will influence the assay sensitivity required to detect differences in sperm fertilizing potential to determine the most fertile ejaculates. Interaction with the zona pellucida (ZP) and oolemma are two bioassays suggested to assess variation in sperm fertilizing potential. Interaction with receptors on the oolemma appears to contribute to the variation in sperm fertilizing potential observed within fertile populations. Ref. 276\64.12.

1995. Theriogenology 43: pp. 769-775.
This study was designed to evaluate the proportion of males with spermatozoa detectably less fertile than the spermatozoa from other males. The proportion of pairs in which the males sired equivalent numbers of offspring were 0.42, 0.18, 0.33 and 0.09 for trials with fresh boar semen, liquid-stored boar semen, frozen full semen and fresh rab bit. The calculated proportion of males with less fertile spermatozoa were 0.36, 0.57, 0.42 and 0.70, respectively. Although these differences in fertility would not be apparent in some management systems, a high proportion of ejaculates had sperma tozoa that were detectably less fertile.

1988. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 10-14.
The present study was undertaken as part of a heifer management trial that involves crossbreeding Hereford heifers with Angus, Gelbvieh and Longhorn sires. The objective of measuring pelvic areas was to ascertain whether pelvic measurements taken at different times had any relationship to the incidence of dystocia. The data collect during the last two years would indicate thus far that selecting heifers based on pelvic area would serve no purpose in preventing dystocia but that selecting bulls (or breeds) that are known to sire calves with low birth weights would result in a lower incidence of dystocia.

1989. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 23-26.
This study evaluated calving ease in first calf heifers for births resulting from mating with Texas Longhorn, Angus or Gelbvieh bulls. We also examined livability and gains of these calves. We concluded that birthweights were lighter for Longhorn cross calves than for Angus or Gelbvieh crosses. Results for dystocia scores were similar: scores for rths resulting from Longhorn sires were the lowest. Livability for Longhorn crosses were the highest, but gains to weaning were signficantly lower than for the Angus crosses.

1992. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 11-16.
This presentation discusses several management methods for first-calf heifers which were evaluated at the Sierra Field Station over several years. Bulls were selected from several herds representing each breed. Births of heifer calves resulted in a significantly lower dystocia score and required assistance less than as frequently as di d births of bull calves. Calf birth weights varied among sire breeds, thus calving success measures also varied among years in this study.

1991. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 30-32.
An attempt was made to look at differences in weight gain and dollar return of stocker cattle managed under two levels of stocking over a three year period. High stocking rates returned more dollars per acre in the first two years of this trial although return per head was higher for the low stocking rate groups because of higher gains. The results from 1990-91 indicate that under severe feed conditions a lowered stocking rate is favored economically on either the per head or the per acre basis.

1992. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 5-9.
The recent emphasis on value-based marketing and carcass predictability has caused many cow-calf producers to take a second look at estrus (heat) synchronization and artificial insemination (AI) programs. The improved selection technology now available with EPD's (expected progeny difference) allows producers the opportunity to maximize uniformity and predictability by utilization of proven AI sires. Synchronization of estrus and AI go hand-in-hand. By concentrating the largest percent of heat cycles to a short period of time, a producer is able to save time in heat detection, breeding and in the subsequent calving season.

1992. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 23-26.
Several studies have been designed to synchronize the recovery of immunized heifers in an attempt to develop management strategies for large groups of heifers where it is difficult to make culling decisions early. In this manner, all heifers could be managed identically until culling decisions are made. Under this management strategy, the immunization procedure would be temporary and recovery of replacement heifers could be synchronized so that this population of females would still calve at two years of age. New vaccine adjuvants are currently being evaluated to determine their usefulness under this type of management scheme. Ref.277\64.13.

1980. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: p. 29.
At the Sierra Field Station there are approximately 250 commercial Herefords, 60 purebred Polled Herefords, and 60 replacement heifers. All mature cows at the Station are assigned to a research project. The size of the experimental groups range from 10 to 35 head of cows and depend upon the experimental design, pasture records and indiv idual production records are kept on all cows, calves, and bulls. All animals are weighed a minimum of five times per year. Cows are pregnancy tested each year, and the open cows are culled unless the experimental design states otherwise.

1985. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: p. 23.
Preliminary results from this trial indicate that 1) implanting heifers with Ralgro at 2-4 months of age produces variable results; 2) implanting heifers with Ralgro following weaning showed no beneficial effect; and 3) implanting heifers with Ralgro just prior to the breeding season inhibits sexual maturity (estrus) and lowers the pregnancy rate.

1997. Proc., Western Section, American Society of Animal Science. p. 48.
Three herds of crossbred beef calves were tested for fecal shedding of Campylobacter jejuni and protozoal eggs from Cryptosporidia parvum and Giardia duodenalis. Infection impact on preweaning ADG and adjusted weaning weight was determined. Fecal grab samples were randomly obtained from calves at 2-3 months of age and again at weaning. Calves were identified as positive or negative for each parasite. Statistical analysis included location and sex effects. Ref.307/64.45.

1993. Proc., UC Sierra Foothill REC Beef and Range Field Day: pp. 1-4.
A number of experiments on supplementation of steers under annual range conditions at the UCSFREC have demonstrated that supplements may affect growth, but profit per acre may not always improve. Maximal gain per animal is not always the most important production criterion. The effects of supplements on forage intake are complex in grazi ng cattle where interactions between grazing, supplement intake, forage availability and conditions may modify normal mechanisms that regulate intake. There is evidence of a positive response in steer weight gain & dollar return/acre when small amount of energy are fed in the spring.

1988. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 1-5.
A 114-day supplemental feeding trial involving a total of 144 English-bred steers averaging 496 pounds was conducted to evaluate urea, bypass protein, and urea plus bypass as range supplements. The urea-based supplement appeared not to be as palatable as the bypass and urea plus bypass protein supplements. The major bypass ingredient in the byp ass and bypass plus urea supplements was corn gluten meal. Steers consuming the bypass plus urea supplement gained the most weight and returned more dollars over supplement cost.

1989. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 1-6.
Steers consuming bypass protein supplements gained the most weight and returned more dollars over supplement cost. It is not yet clear what added benefit, if any, the combination of urea and the corn gluten meal may have. Steers in the low stocking density groups (5.33 acres/hd) gained more weight than the high stocking density groups (2.6 acres/hd) across all supplement treatments. As a result, the lower stocking density groups returned more dollars per head. Dollar return per acre favored the high stocking density groups. Variations in overall average daily gains between years may be a reflection of residual dry matter differences.

1990. California Agriculture 44(2): pp. 12-15.
In two range feeding trials to evaluate supplemental nitrogen and/or bypass protein source and stocking densities, calves at a low density gained more weight than high density groups. Dollar return during the supplementation phase, however, was highest from high density groups fed a combination of urea and corn gluten meal.

1993. California Agriculture 47(3): pp. 25-26.
This trial illustrates that copper-oxide-wire particles are an effective and simple method for preventing or treating copper deficiency in cattle. Study results indicate that oral administration of copper-wire particles was effective, cheap, safe, and convenient in preventing or treating copper deficiency. Such a deficiency can retard growth in cattle.

1983. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 31-37.
Selenium deficiency in cattle was originally thought to be a problem primarily confined to northern California. There is now evidence that selenium deficiency is widespread throughout the state. The selenium pellet administered in a single operation, offers a safe, economic, and effective means of preventing selenium deficiency in grazing attle for a period of two years. During that period, it raises selenium concentrations in the blood and other tissue from deficient to normal levels.

1993. Proc., UC Sierra Foothill REC Beef and Range Field Day. pp. 1-4.
A number of experiments on supplementation of steers under annual range conditions at the UC SFREC have demonstrated that supplements may affect growth, but profit per acre may not always improve. Maximum gain per animal is not always the most important production criterion. The effects of supplements on forage intake are complex in grazing cattle where interactions between grazing, supplement intake, forage availability and conditions may modify normal mechanisms that regulate intake. There is evidence of a positive response in steer weight gain & dollar return/acre when small amounts of energy are fed in the spring. Ref.166\61.49.

1987. UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 10-18.
In California it is estimated that the cost of maintaining the range beef cow accounts for approximately $400.00 annually. One of the major ways to increase profitablility of the range cow herd is to reduce this cost. Sixty percent of this $400 represents feeding the cow. Body condition scoring was developed from an Australian method an d can be used by anyone working with cattle to assess the fatness or condition of cows, calves, or bulls. It can serve as a valuable management aid in cattle production.

1984. Compendium on Continuing Education 6(12): p. 10.
Infectious bovine keratoconjunctivitis (IBK) is a widespread, highly contagious ocular disease of cattle. The incidence of the disease is variable, but in some herds 45% of the calves may develop ocular lesions during a summer. Economic losses in feedlot calves with IBK in one or both eyes include 260-day postweaning body weight decreases of 35 and 47 lb respectively. Other costs that are attributable to IBK include drugs and labor for the treatment of infected calves and loss of income from milk discarded because of antibiotic residues.

1987. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: p. 32.
The effectiveness of topically applied furazolidone (NFZ), and subconjunctivally administered penicillin G for the treatment of infectious bovine keratoconjunctivitis (IBK) were compared to that of parenteral and combined parenteral oral therapy with oxytetracycline (OTC). All of the calves were examined 3 times weekly. Calves treated with OTC had the best response to therapy, while those treated with topical NFZ had the poorest response. The response of the calves to the penicillin G was significantly poorer than that observed in the OTC treatment group. Seemingly, OTC is superior to NFZ and penicillin G for the therapy of active IBK.

1990. California Agriculture 44(2): pp. 11-12.
Two field studies showed that a widespread pinkeye epidemic in a beef herd can be effectively treated with injections of long-acting oxytetracycline, followed by feeding the antibiotic in the ration. When the disease is less prevalent, injecting affected animals with penicillin or oxytetracycline is effective.

1985. J. Vet. Pharmacol. Therap. 8: pp. 55-61.
Studies were undertaken to determine the effectiveness of an oxytetracycline HCl formulation for the prophylaxis and treatment of chronic Moraxella bovis ocular infections in calves. Two separate experiments were performed. For the first, calves were separated into two groups and the eyes were infected with M. bovis. The eyes of these calv es were observed and cultured for 37 consecutive days. The cultures from the five treated calves were negative after the first antibiotic administration and remained so for 14 days.

1980. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 33-37.
Although supplementation of growing heifers may be economically marginal when interpreted solely on the basis of weight gains, other considerations such as presupplemental ADG, increased stocking rate of irrigated pasture, and specific breeding weight and time goals would determine the most appropriate management practice to be used durin g the growing phase. The data reported here indicate that although irrigated pasture is a very good growing diet, energy supplementation will increase ADG; however, an optimal system of supplementation such as feeding heavily for two weeks followed by no grain for two weeks should be employed. The addition of monensin is also recommended.

1991. Proc., UC Sierra Foothill REC Beef and Range Field Day. pp. 46-47.
All phases of grazing management must be considered to optimize animal production from irrigated pasture. These should include a preventive animal health program, a pasture management plan, an animal management plan and the selection of the type of livestock to be grazed within the overall management system to be the desired objectives. Ref.71\61.26.

1985. UC Sierra Foothill Range Field Station Beef and Range Field Day: p. 24.
To take advantage of the high productivity and low production cost of an irrigated pasture, the use of high-energy supplements and monensin sodium in the diet of grazing heifers is recommended. Even with their use, however gain has not always been in the recommended range of 1.25 pounds per day or better. Recent studies concerned with the growth and development of replacement beef heifers bred to calve as two-year-olds have shown that protein-energy supplementation for such heifers grazing irrigated pasture will enhance average daily gain over conventional energy supplementation and monensin was additive.

1984. California Agriculture 38(11-12): pp. 9-10.
Recent studies concerned with the growth and development of replacement beef heifers bred to calve as two-year-olds have shown that protein-energy supplementation for such heifers grazing irrigated pasture will enhance average daily gain over conventional energy supplementation. Variable performance on irrigated pasture led to our investigation of various levels of protein and energy supplementation as a means of increasing average daily gain to produce heifers of adequate breeding weight.

1977. California Agriculture 31(4): pp. 18-19.
Cereal straw can be fed as a major portion of a growing ration with little if any energy available for production. Better growth can be obtained when cottonseed meal rather than urea is used as a nitrogen source to supplement straw. A least-cost program will result in a least-cost ration for a given set of specifications and feed prices. However, the least-cost ration does not ensure least-cost gain. More work is necessary on feeding cereal straws, especially on factors affecting intake and net energy values.

1978. California Agriculture 32(11): pp. 14-15.
Rice straw is palatable and a satisfactory feed for pregnant beef cows, provided protein, mineral, and vitamin requirements are met. Diets containing high levels of barley straw are unpalatable even when supplemented with protein, minerals, and vitamins. They should not be fed to pregnant beef cows unless special precautions are taken to ensure that adequate quantities of nutrients will be consumed.

1978a. J. Anim. Sci. 46: pp. 878-883.
Irrigated pasture grazing trials were conducted during three grazing seasons (years) to investigate systems for rearing early-breeding replacement beef heifers. Seven-to 8-month-old weaner beef heifers grazing irrigated pasture were supplemented with barley. Supplemental treatments were (1) none, (2) three times per week (MWF), (3) daily (fed weekly-intake limited by salt to be consumed over 7 days) and (4) same amount as (2) and (3) would consume in 2 weeks. Supplementation increased ADG and supplementing for 2 weeks followed by no grain for 2 weeks in general increased ADG more than other supplemental treatments.

1978b. California Agriculture 32(7): pp. 6-8.
Many studies have shown irrigated pasture to be a good growing ration. Others have shown better results with grain used to supplement irrigated pasture. In preliminary trials at Davis, beef calves on irrigated pasture barley, supplemented at the rate of 20 percent of their expected total dry matter intake (approximately 1 kg/day), did not improve gains significantly, but supplementation did permit a marked increase in stocking rate. In conclusion, phases of management, genetics, and nutrition must be considered if rearing replacement heifers, and for early breeding (bred as yearlings to calve as 2-year-olds), and a good preweaning diet is necessary.

1981. California Agriculture 35(3-4): pp. 8-9.
Although supplementation of growing heifers may be economically arginal when evaluated solely on the basis of weight gains, other considerations, such as preweaning average daily gain (ADG), increased pasture stocking rate, and specific breeding weight and time goals, would determine the most appropriate management practice to be used during the growing phase. The data indicate that energy supplementation of irrigated pasture increases ADG. Only heifers with above-average ADG at weaning should be selected as replacements and fed a diet for continued growth to reach 650 pounds by 14 to 15 months of age.

1972. J. Range Manage. 25(2): pp. 96-99.
Supplementation of a low protein, high-fiber, dry annual-range forage by irrigated pasture appears feasible. Data indicate that irrigated pasture can be used to increase the amount, or improve the quality, of beef production, and that it can compete economically with cottonseed meal as a supplemental protein source for cattle grazing dry annual-range forage.

1996a. 1974. J. Range Manage. 27(3): pp. 192-194.
Three groups of pregnant beef cows grazing dry native annual range were either supplemented with pelleted cottonseed meal (0.90 kg/head daily), a pelleted mixture of 75% feedlot manure-25% barley (ad lib.), or received no supplementation for a period of 84 days. Cows were induced to consume the manure pellet on range by accustoming them to the manure-barley pellet in a preliminary period of feeding in a drylot. A marked response occurred to both supplements as measured by cow weights at calving and weaning weight of the calf.

1982. Proc., Western Sec. Amer. Soc. Anim. Sci. 1982 33: pp. 1-4.
The present study was undertaken to reexamine the necessity to supplement breeding cows with vitamin A under northern Californian range conditions. The results support and reaffirm the conclusion on Hart and Guibert (1933) that mature breeding stock, under normal range conditions in northern California, can store sufficient vitamin A in their livers during the green season to meet their demands throughout the year. While a deficiency of vitamin A can have serious economic consequences, the probability of a deficiency occurring appears to be relatively remote. Therefore, vitamin A supplementation as an insurance against a deficiency needs to be supplied on a minimal cost basis.

1988. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 6-9.
Body condition is a more reliable guide for evaluating nutritional status than live weight. Body condition scoring is easy to learn and useful when practiced by the same person in the same herd over several years. Nutrition and reproduction decisions are made with more precision where a body condition scoring system is routinely used.

1979. California Agriculture 33(3): pp. 14-15.
The objective of these studies was to determine the effects of injections of selenium, vitamin E, and combinations of the two on post-weaning weight gains of beef calves raised in Se-deficient areas. Treatment with Se produced significant increases in weight gain over controls. Improvements ranged from 16% to 59%, with an average of 43% on a trial-by-trial basis. Additions of vitamins E, A, & D to Se produced no significant increase in weight. Treatment with vitamin E alone produced a significant increase in gain over controls in one of three comparisons, but the increase was significantly less than that produced by Se treatments.

1978. J. Nematol. 10: pp. 331-341.
Hetertylenchus autumnalis was found in six northern California counties surveyed, and the incidence of nematode infection of face flies ranged from 4.7 to 43.8%. Intensive studies at a cattle ranch in Yuba County showed that population densities of the host and nematode infections were highest in flies from cow pats receiving full sun. Average host population density was 105.7 puparia per pat, and nematode infection averaged 38.6%. Pats in partial sun averaged 13.5 puparia and 13.1% nematode infection. No face fly was recovered from shaded pats.

1979. Environ. Entomol. 8: pp. 537-540.
Face flies of both sexes infected with the nematode, visited the faces of cattle and fresh cattle dung. However, female flies greatly outnumbered males at both sources. Generally, infected male flies found on cattle and dung contained young nematodes. In contrast, infected females on cattle contained nematodes of all ages, and most infected females from dung contained older nematodes. The propensity of healthy female flies to visit faces of cattle and dung depended on their gonadotrophic age. The majority of flies with immature eggs were found on cattle while the majority with mature eggs were found on dung.

1996. M.P.V.M. Thesis, Univ. of Calif., Davis. 27 pages.
Sixty-four Herefore/Shorthorn cross calves, raised under foothill conditions at Sierra Foothill Research and Extension Center, were used in a field trial to determine the efficacy of lasalocid and decoquinate, or remained as non-medicated controls. Fecal Samples were collected and examined at the beginning and end of the study. The overall oocyst shedding rate was lower than those reported in previous studies. The mean body weights per group increased by 5.0%, 5.1%, and 3.0% for the lasalocid, decoquinate, and control groups, respectively. Ref.310/64.48.

1996a. 1987. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 19-25.
Cooper's ear tags (Code 20) provided excellent control of horn flies for the period June 9 to September 9, 1986. A cow herd was sprayed with 0.25% Deltox which kept fly populations low for 6-7 weeks, after which the herd was exposed to 1% Warbex dust bags. The dust bags had little effect. None of the treatments was effective against face flies. Ectiban tapes reduced horn fly levels in some cases.

1996. UC Sierra Foothill REC Beef and Range Field Day. pp. 31-33.
In a clinical research trial conducted at the Sierra Foothill Research and Extension Center in 1995, we looked at the effect of prevention of coccidiosis on weaning cattle. Our conclusion was that coccidiosis prevention, in weaned calves that are minimally exposed to coccidia may have important production benefits. Ref.279\64.15.

1980. J. Anim. Sci. 50: pp. 145-152.
Although grazing cattle generally freely consume supplemental salt, the necessity of providing sodium additional to that in the feed has almost universally been accepted without evaluation. Techniques proposed for detection of Na inadequacy of cattle are reviewed and it is concluded that parotid salivary Na:K ratio and adrenal histology are the most sensitive indices of Na inadequacy. However, while saliva is a readily sampled body fluid, narrow Na:K ratios are not always associated with production responses to supplemental Na.

1983. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 25-30.
Reviews range cattle nutrient requirements and some supplementation considerations. States Vitamin A liver (100-230 mg/g) and blood plasma (15-31 mg/dl) concentrations for cattle on dry range. Vitamin A levels are probably adequate in cattle on foothill ranges if cows graze green forage for a short period during the year. Phosphorus levels in dry forage are below NRC requirements for lactating cows. Energy and protein are deficient for a considerable portion of the grazing year. In one trial, fed protein and energy was substituted for forage at the rate of 68%.

1984. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 17-19.
During periods of low feed (energy) intake, the cow reduces her energy expenditure, and additional supplementary feed goes toward an increase in body weight and energy expenditure. When range forage is of good quality (March - May at the Sierra Field Station) energy reserves of cows are restored to similar levels, largely independent of previous levels of supplementation. The results of this experiment to date indicate that when cows are conservatively stocked on cleared foothill range in most years, supplementary feeding is unlikely to be profitable. The study is still in progress.

1985a. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 4-7.
The objective of this study was to measure feed (energy) intake and energy loss by cows grazing on range so energy balance could be calculated. Note that the greatest difference between energy intake and expenditure occurs in the green season when the cows gain in body tissue. These data show the importance of matching the cows' energy expenditure with the availability of forage and the remarkable elasticity of the cow to reduce energy expenditure in periods of low feed availability.

1985b. UC Davis Dept. of Animal Sci. and Coop. Ext. Beef Day: pp. 7-13.
The results of this six-year field experiment involving over 1000 cow years demonstrates that supplementation can increase the productivity of range cows. Although no significant response was obtained in pregnancy percentage to supplementary feeding, the data does indicate that cows of low body weight at calving are the ones most likely to be open. If any supplementary feeding is practiced, these low body weight cows should be the first to receive supplements. While this experiment was conducted over a period of 6 years and encompassed variable seasonal conditions, it was conducted at only one site.

1989. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 9-11.
The overall objective of an management system for range cows is to maximize net income in relation to the investment in cows, land and other resources. Profitability of the operation depends on the costs of achieving high pregnancy and weaning rates, and high milk production in the cow. Supplementation of the cows increased weaning weight of the calves when comparing them to the non-supplemented group, but caused an even greater increase in costs. Results may differ with a breed of cow with higher milk production or higher stocking rate.

1980. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 38-39.
Seasonal variability in supplement consumption by livestock is discussed as are means of measuring consumption in grazing animals. An electronic gate feeder is discussed which provides known amounts of supplement to individual cattle grazing in a group situation with other cattle.

1980b. Proc., UC Sierra Foothill REC Beef and Range Field Day. pp. 16-20.
A fundamental characteristic of the world's rangelands is the variation in quantity and quality of forage it makes available to grazing animals. This variation results from responses of pasture plants to climatic variables, particularly temperature and rainfall. Data show that the organic matter digestibility and therefore, available energy from annual range forage falls to low levels in the summer-fall period. Thus, the forage ingested by range cattle varies markedly and predictably with the growth cycle of the range plants.

1982. J. Animal Sci. 54(3): pp. 500-503.
A portable self-contained unit which permits supplementation of individual cattle or groups of cattle grazing common range is described. Each unit has four individual feed bunks with an electronic gate that controls entry of cattle to the supplements. When the electronic gates are in continuous operation, they rapidly discharge the lead-sulfuric acid storage batteries. Therefore, a circuit was devised which reduces this demand at all times except when cattle were feeding from the unit. The batteries are recharged by either solar panels or an alternator driven by a small gasoline motor.

1980. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 21-22.
One hundred and seventeen weaner steers were drenched with Thibenzole, weighed, and divided into four groups by stratified randomization on a body weight basis. The four groups of steers had an initial mean shrunk body weight of about 200 kg. In order to have differential stocking rates, the number of animal per group was varied as the fields were relatively uniform in size. During the trial, individual body weights were taken at weekly intervals on steers corralled and weighed directly from pasture. Our conclusion, for optimal use of foothill range for liveweight gain in steers, high stocking rates for the short period when the forage is of high nutritive value are required.

1989. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 20-22.
This article summarizes infectious bovine keratoconjunctivitis (IBK), treatment, prevention, clinical signs of infection, & management.

1996. Proc., UC Sierra Foothill REC Beef and Range Field Day. pp. 35-41.
Preliminary results from research aimed at identification of optimal supplementation strategies for range beef cows shows that cows in poorer condition may be supplemented to improve reproductive performance. When body condition dropped below 5.5, cows were supplemented for the next three months. Performance of the cows in the strategic supplementation was improved over those never supplemented, at reduced cost compared to a group always supplemented. Interactions with forage available to graze were observed, and are being explored in further research. Ref.275\64.11.

1994. Appl.Anim.Behav.Sci. pp. 257-261.
Twelve polled Hereford bulls were subjected to annual sexual performance evaluations starting at 12-13 months of age and continuing to 5 years. Significant year effects were obtained for ejaculation frequency, frequency of mounts without ejaculation and the proportion of mounts that culminated in an ejaculation. As yearlings, the subjects exhibited more mounts, fewer ejaculations and lower ejaculation-to-mount ratio than in years 2 through 5. Increases in mating efficiency between years 2 through 5 were not significant. Some individual year-to-year variation in sexual performance was noted until the bulls reached 4 years of age. Ref.270\64.06.

1984. Appl.Anim.Behav.Sci. 13: pp. 309-320.
Methods to increase the productivity of beef cattle include twinning and multiple fostering of calves on nurse cows, but little is known about the capacity of cows to rear more than one calf in a rangeland environment. The hypothesis that mother-offspring bonds are weaker than twins than with singles was supported by the fact that mothers bearing twins groomed their offspring less than mothers with singles, and twins were normally found at greater distances from their mothers than singles. Most long-distance cow-calf separations resulted from the cow moving to feed or to obtain water. Ref.271\64.07.

1991. J.Anim.Sci. 69: pp. 1041-1046.
The objective of this investigation was to determine the extent to which the sexual performance of adult bulls (18-24 mo. of age) can be predicted by prepuberal sexual behaviors. Tests were administered to 121 polled Hereford bulls to determine whether adult sexual performance (especially serving capacity or ejaculation rate) was related to mounting of estrous females at 6 mo. of age, age at first ejaculation, frequency of sexual behaviors in heterosexual interactions or the frequency of male-male mounting exhibited in all-male groups. None of the above measures reliably predicted adult serving capacity. We concluded that the sexual behaviors of prepuberal beef bulls were of limited usefulness in predicting adult sexual performance. Ref.272\64.08.

1991. J.Anim.Sci. 69: pp. 1019-1027.
This study describes maturation-related changes in the sexual and aggressive behaviors of Hereford bulls. Two groups of 13 and 14 bulls, respectively, were tested for sexual and aggressive behaviors every 3 mo from 3 to 24 mo of age. We conclude that sexual performance data obtained in serving capacity tests administered to yearling bulls before 18 mo of age may underestimate the mating potential of certain individuals. Aggressive behaviors are sufficiently well developed in males by 18 mo of age that prolonged bouts of fighting may reduce the reliability of sexual performance data when testing males in groups. Ref.273\64.09.

1980. Proc., UC Sierra Foothill Range Field Station Beef and Field Day: pp. 5-15.
Animal data were analyzed by computing standard deviations for 1) cow weights at breeding, weaning and calving, and at beginning and end of supplementation, and 2) calf weights at birth and weaning (adjusted to 205 days). Using years as replications mean cow and calf weights for the two management systems were compared using the Student's "t" test. An Animal Unit Month (AUM), where used, was defined as one 1000-lb cow. A number of management options used in the study would be useful to part-time farmer-ranchers, especially where family labor and relatively-inexpensive irrigation water are available.

1989. J. Range Manage. 42: pp. 415-420.
Objectives of this study were to construct a model to describe seasonal changes in steer average daily gain (ADG); to observe changes in nitrogen concentration and in vitro organic matter digestibility related to time of season and ADG; and to relate the phenological progress of maturation of rose clover to ADG, nitrogen concentration and in vitro organic matter digestibility.

1993. Proc., UC Sierra Foothill REC Beef and Range Field Day: pp. 11-15.
Current systems for marketing beef cattle and their meat products are changing from average-based to new value-based trading systems. With value-based marketing, cattle will be traded based upon the yield and quality of the usable beef they will produce, rather than their weight alone. The purpose of this paper is to discuss several aspects of value-based marketing of beef with special attention to three questions: 1) Why do we need value-based marketing? 2) how will value-based marketing be implemented? 3) What are the implications for cattle producers?

1983. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 15-16.
In order to improve the productivity of ruminants on pasture it is necessary to have a better understanding of the energy transactions occurring in the animals during the different periods of the production cycle. Up to now the caloric requirements of grazing beef cattle can only be estimated from summations of the energy cost of the different physiological (growth, lactation, pregnancy) and physical (eating, milking, etc.) activities. This present work is directed towards the estimation of the total daily energy expenditure and energy intake of beef cows grazing annual grasslands with different levels of alflafa supplementation.

1986. Ph.D. Thesis, UCDavis: p. 40.
The energy expenditure (EE) and the feed intake (FI) were measured in beef cows grazing annual rangeland. The cows were divided in three groups that received 0 (group 1), 2 (group 2), and 4 (group 3) kg of alfalfa cubes per day as supplement from August to February. Cows from group 1 had significantly lower EE than cows from groups 2 and 3 in measurements immediately preceeding and following calving. Calves from cows in group 3 gained weight faster than calves from the other two groups. Cows from group 3 also had significantly higher total intake of DOM than cows from the other two groups, indicating an additive effect of the supplement.

1988. Immunopathol. 18: pp. 53-66.
Monoclonal antibodies were produced against serum-derived bovine immunoglobulin E (IgE). Culture supernatants of hybridomas were initially screened by enzyme-linked immunosorbent assay (ELISA). Supernatant-derived antibodies were concentrated and further characterized using ELISA, reverse cutaneous anaphylaxis, immunohistochemical staining, and immunoblotting of IgE-containing samples separated by SDS-polyacrylamide gel electrophoresis (PAGE). Eight monoclonal antibodies showed specificity for bovine epsilon immunoglobulin heavy chain. These antibodies will be useful in research applications and in diagnostic assays.

1972. J. Animal Sci. 34: pp. 1003-1010.
Similar groups of ungentled range weaner beef heifers were reared separate from other cattle at the University's Davis campus and Range Field Station. While there were considerable differences in the abilities of the observers to detect estrus it was shown that it was possible for a skilled observer, with the aid of a marker animal, to detect a very high percentage of the heats with twice daily observations.

1989. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: pp. 27-30.
The carcass data indicates the Longhorn crosses will grade equally to the Angus crosses. They may have a slight advantage because of lesser total fat, as their yield grade was approximately one half a yield grade lower. Numbers are small, therefore it is difficult to make a strong conclusion. This trial will have two more years of feedlot and carcass data to be analyzed.

1985. Proc., UC Sierra Foothill Range Field Station Beef and Range Field Day: p. 12.
Administering up to 8 selenium rumen pellets to yearling calves showed no harmful effects to the cattle. The higher blood samples were in the magnitude of 10 less than the toxic levels. All tissue samples were within the safe range except for those from the kidney, which was only 0.3 ppm above the stated safe maximum of 7.6 ppm. There was no animal health problems that could be attributed to selenium levels. There was no significant difference in ADG between groups.

1984. The effects of multiple selenium rumen pellets in feeder calves. Thesis, Univ. of Calif., Davis: pp. 1-29.
Although some tissue and blood levels were significantly different (p<0.05), no significant differences were observed for measured health and growth parameters for supplemental levels of 2 to 8 rumen selenium pellets per animal. It is unlikely that cattle would accidently be repelleted more than once or twice under field conditions. Based on our observations in Hereford feeder steers, accidental repelleting as might happen under field conditions would not harm these steers.

1991. Am. J. Vet. Res. 52: pp. 1866-1870.
Five groups of Hereford steer were monitored for 293 days. One group of 3 was not given selenium supplementation; the other 4 groups of 3 steers each were given 2, 4, 6, or 8 reticulorumen selenium pellets. Health, body weight, and blood selenium concentration were monitored during the study. At the finish, steers were slaughtered, and various tissues from the carcasses were analyzed for selenium content. Initial blood selenium concentration did not differ significantly among groups. Analysis did not indicate risk to human beings consuming tissues from these steers.