The objective of this study was to assess the effect of low stress (LS) handling of beef calves on weight gain and calf activity associated with the weaning process. Cattle were of Angus and Angus cross breeding from two separate herds in Virginia. Handlers for the LS groups went through a short training session. Handlers for the Control (C) groups did not have any special training and handled their group as they would have with no adjustments. Handling and calf activity were monitored each time (6 times) the cows were worked from calving through one month post-weaning. Weights were taken from birth to one month post-weaning. During the week post-weaning the C calves averaged a gain of 4.38 lbs. and the LS calves averaged a gain of 16.94 lbs. One month post-weaning the C calves averaged a gain of 49.01 lbs., while the LS calves averaged a gain of 68.6 lbs. This showed a difference (p < 0.0001) between handling method for weight gain in calves for one week and one month post-weaning. Pedometers were used to assess calf activity post-weaning. Steps per hour (SPH) for the week post-weaning was numerically higher for those calves handled conventionally and not trained for weaning. The C calves averaged 1048 to 1629 SPH for the first three days, where the LS calves averaged 443 to 644 SPH for the first three days. Additionally, the artificial insemination conception rates (AICR) were calculated in each herd and treatment groups compared, however results were equivocal. This study demonstrated that handling cattle using low stress techniques can make significant improvements with regard to weaning weights and has potential to increase other areas of production in beef cattle. / Master of Science

An expert system to predict the fertility of beef heifers was developed using the A.I. Toolkit KAPPA-PC 2.33. The knowledge base was developed from scientific literature and from a beef cattle reproduction expert. The expert system computes an evaluation age, age both at the start and end of the breeding season, and weight per day of age to classify a heifer as having either a 3LOW2, 3GOOD2, or 3EXCELLENT2 likelihood of conception. The expert system summarizes the information that is entered into the computer and creates a text file of the summary. It also gives explanations for every prediction to help identify and alleviate any problem areas that may affect a heifer1s ability to reproduce. The program requires an IBM compatible computer installed with Windows 3.13 or greater. From simulated data for purebred or crossbred British cattle, there was 72% prediction agreement between the expert system and the expert. From analysis of historical data of Hereford-Angus crossbred cattle, heifers categorized as 3LOW2 and 3GOOD2 had significantly higher observed pregnancy rates than expected for each category. There was no significant difference between observed and expected pregnancy rates for heifers in the 3EXCELLENT2 category. Pregnancy rates for post-weaning and pre-breeding evaluations for the 3LOW2 heifers were found to be lower from the combined 3GOOD2 and 3EXCELLENT2 heifers at P=.03 and P=.06 respectively. Observed successful calving rates for heifers categorized as 3LOW2, 3GOOD2, and 3EXCELLENT2 did not differ significantly from the expected calving rates for each category. / Master of Science

The objective of this study was to determine the effects of dietary supplementation of eicosapentanoic (EPA) and docosahexanoic acids (DHA) on reproduction in beef females. In experiment 1, cows (n = 31) were individually fed rumen protected fish meal (FM) or no fish meal (C) supplements. Estrus was synchronized and ovulation induced on d 37. Ovarian follicular growth and diameter were determined by ultrasound on d 35 and d 37. Serum progesterone (P4) profiles were analyzed on d 37 through d 52. On d 52 cows were cannulated, primed with estradiol-17&#946; at -240 min, and stimulated to release PGF2&#945; by oxytocin injection at 0 min with blood sampled every 15 min from -30 min to 240 min. Supplement type did not affect (P > 0.05) follicular diameter, follicular growth or P4 concentrations. In cows fed FM, prostaglandin metabolite (PGFM) concentrations tended (P &#8804; 0.10) to be reduced at 0, 30, and 60 min. In experiment 2, crossbred heifers (n = 214) received FM or C concentrates with corn silage from 30 d before estrous synchronization until 14 d after artificial insemination (AI). Serum fatty acid profiles were determined in five heifers from each group . Estrus detection and AI were conducted from d 37 through d 39. Dietary treatment increased (P < 0.05) EPA and DHA concentrations. Dietary treatment did not affect estrus response or AI conception rates and pregnancy rate. Supplementation of FM increased EPA and DHA concentrations but did not affect reproductive factors. / Master of Science

Call number: LD2668 .T4 1985 M52 / Master of Science

"December, 2004." / Bibliography: leaves 229-251. / xvi, 265 leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, School of Agriculture and Wine, Disciplines of Animal Science and Biometrics SA, 2005?

Two experiments were conducted to determine the effects of daily (D) vs alternate day (AD) supplementation of soybean meal (SBM) or wheat middlings (WM) on forage organic matter intake (OMI), ruminal digesta kinetics, total tract digestibility, and ADG of steers consuming low quality forage. In Exp. 1, five Angus x Hereford steers (403 �� 32 kg) fitted with rumen cannulas were utilized in a 5 x 5 Latin square design. Steers were individually fed low-quality (5.3% CP) fescue hay ad libitum and were randomly assigned to one of five treatments: no supplement (CON); WM fed daily (WMD); WM fed every other day (WMAD); SBM fed daily (SBMD); and SBM fed every other day (SBMAD). Supplements were formulated to meet 100% of degradable intake protein (DIP) and metabolizable protein (MP) requirements. Supplementation increased (P<0.05) hay and total OMI (g���kg��������BW�����) and total OM digestibility (%) compared to CON. Daily supplementation increased (P<0.05) hay and total OMI and hay and total OM digestibility when compared with AD supplementation. Hay OMI and hay OM digestibility was greater (P<0.01) for SBM compared to WM, but total OMI and total OM digestibility was not different (P>0.38). In Exp. 2, 96 Angus crossbred steers (280 �� 32 kg) were blocked by weight (three groups) into 12 pens in a randomized complete block design. Steers were fed low-quality (6.2% CP) fescue straw ad libitum, and one of four supplements formulated to meet 100% of the DIP requirements: WM fed daily (WMD); WM fed 3d/week (WMAD); SBM fed daily (SBMD); and SBM fed 3d/week (SBMAD). Straw OMI was greater (P<0.03) for D compared with AD supplemented treatments and for SBM compared with WM supplemented treatments. Total OMI was greater (P<0.01) for D compared with AD supplemented treatments, however, SBM had similar total OMI when compared with WM supplemented treatments. Daily supplemented steers had greater (P=0.03) ADG when compared with AD supplemented steers. Despite having lower forage intake and similar total OMI, steers consuming WM had higher (P<0.01) ADG when compared to steers consuming SBM. / Graduation date: 2003

Graduation date: 1993

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 174-182). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2001. / Typescript. Vita. Includes bibliographical references (leaves 174-182). Also available on the Internet.

Genetic parameters were estimated using 8086 weaning weight records of Mashona cattle from commercial herds in Zimbabwe, through Derivative-free Restricted Maximum Likelihood (DFREML) procedure fitting an individual animal model. All known additive relationships among animals were incorporated and all sires were assumed to have been bred by unknown parents. A simulation study was carried out to estimate the amount of bias in the estimated genetic parameters caused by the failure to account for the true relationships among the breeding animals. / Genetic differences between the weaning weights of Mashona cattle in commercial herds and in small holder herds were estimated using performance records of progeny from 2 reference bulls, 3 bulls from commercial herds, 14 bulls from Makoholi Research Station and 20 bulls from small holder farms. The findings from this study were used as a basis for simulating different strategies of improving the weaning weights of Mashona cattle through the creation of nucleus herds. Estimates ($ pm$s.e) of direct heritability (h$ sb{ rm A} sp2$), maternal heritability (h$ sb{ rm M} sp2$) and the correlation between direct and maternal genetic effects (r$ sb{ rm AM}$) were 0.243 $ pm$ 0.046, 0.392 $ pm$ 0.031 and $-$0.282 $ pm$ 0.081, respectively. When a permanent environmental effect of the dam (c$ sp2$) was fitted, the estimates of h$ sb{ rm A} sp2$, h$ sb{ rm M} sp2$, r$ sb{ rm AM}$ and c$ sp2$ were 0.281 $ pm$ 0.026, 0.113 $ pm$ 0.022, $-$0.269 $ pm$ 0.106 and 0.228 $ pm$ 0.023, respectively. No significant trends were observed in direct breeding values but there was a decline in maternal breeding values. The simulation study indicated that the bias in h$ sb{ rm A} sp2$ and h$ sb{ rm M} sp2$ resulting from the lack of sire pedigrees was trivial if the correlation between direct and maternal genetic effects was high and a large proportion of dams had known pedigrees. / The progeny test showed that both the mean breeding values of the reference sires and the bulls from commercial farms were significantly higher than the mean breeding values of small holder bulls for birth weight (by 1.6 and 1.7 kg, respectively) and weaning weight (by 10.4 and 11.0 kg, respectively). The strategies that selected breeding animals on their maternal genetic values resulted in the highest responses for weaning weight. / It was concluded that maternal genetic values of Mashona cattle should be improved to allow this breed to compete favourably as a maternal breed in commercial agriculture.