Typescript (photocopy) Includes bibliographical references (leaves 223-249) Investigates the relationship between feed conversion efficiency and physiological variables among several lines, generations and breeds of hen fed ad libitum or on restricted amounts of feed; and, of the consequences to egg shell quality of restriction of food supplied to laying hens.

Two experiments measured winter feed waste when cows were fed forage on snow. In the first experiment, feed waste was different (P<0.01) when alfalfa meadow brome mixed hay was fed by bale unroller or bale processor; waste was12.9% vs.19.2%, protein losses were 23.3% and 21.5% respectfully. Feed waste, nutrient replacement and additional equipment costs increased winter feeding costs by $52.50 and $56.25 per head respectfully for a 175 day feeding period. Hay processed into portable bunk feeders, experienced 0% feed waste. In the second experiment, feed waste when barley cereal silage fed either as high moisture round bale silage or chopped pit silage was fed on snow was not different (P>0.05) at 23.2% and 26.8% respectfully. When chopped barley cereal silage or high moisture round bale silage was fed into bunks, feed waste was 0%. Protein losses were 27.1% and 24.2% for the pit and round bale silage. Feed waste, nutrient replacement and additional equipment costs increased winter feeding costs by $164.50 for pit silage and $126.00 for bale silage over a 175 day feeding period. / Animal Science

Graduation date: 1994

This project researched the effects of pullet-phase feed restriction methodology or management and hen-phase diet fortification on female broiler breeder BW and carcass trait uniformity as well as on performance of the broiler offspring. Feed treatments had a significant effect on female BW and carcass trait uniformity at 22 wk of age, with sorting and scatter treatments having the highest uniformity estimates, compared to limited daily, skip-a-day and fibre-diluted programs. Feed and premix treatments did not affect traits after 22 wk of age as individual caging at 22 wk of age unified female BW uniformity across all treatments. Feed treatments did not affect the uniformity of age at sexual maturity, first egg characteristics or production parameters. Premix treatment resulted in decreased shell uniformity and increased uniformity of one of the production parameters, total egg mass. Feed treatments may have a greater effect on female broiler breeder efficiency than previously suggested. / Animal Science

The Cattle Value Discovery System (CVDS) was developed to predict growth and feed requirements of individual cattle fed in groups based on animal, diet, and environment information (Tedeschi et al., 2006). Evaluations of the CVDS using several databases of finishing cattle were conducted to determine the accuracy and precision of the model in predicted dry matter required (DMR) of pen-fed cattle. As well, the sensitivity of the model's predictions to deviations from actual ration metabolizable energy (ME) value was conducted. A meta-analysis of growing and finishing steers evaluated to model's accuracy in predicting DMR of individually fed steers, and the relationships between several model-predicted variables and actual performance and efficiency measures. Results for the first CVDS model evaluation involving pen-fed Santa Gertrudis cattle fed finishing diets revealed that accurate predictions of DMR are possible. The average mean bias for both steers and heifers was 2.43%. The sensitivity analysis of dietary ME values revealed that the model tends to consistently over- and under-predict DMR when the ME values are under- and over-estimated, respectively. However the ranking of pens was not affected by this mis-estimation of diet ME. In the second evaluations, both methods (mean body weight; MBW, dynamic iterative model; DIM) of CVDS were highly accurate and precise in allocating feed to pens of steers fed diverse types of diets and environmental conditions, with both models having a mean bias under 4%. The DIM model was slightly more accurate than the MBW model in predicting DMR. An evaluation of sources of variation revealed that for both models a large portion of the error was random, indicating that further work is needed to account for this variation. The meta-analysis study revealed that the model was able to account for 64% and 67% of the variation in observed dry matter intake (DMI) for growing and finishing steers, respectively. The two model-predicted efficiency measures, the ratio of DMR to average daily gain (ADG) and predicted intake difference (PID), were strongly to moderately correlated with their observed efficiency counterparts. In growing and finishing steers, DMR: ADG was able to account for 76% and 64% of the variation in observed feed conversion ratio (FCR) in growing and finishing studies, respectively. Strong correlations were also found between residual feed intake (RFI) and PID, suggesting that there may also be some similarity on these two measurements.

The Cattle Value Discovery System (CVDS) was developed to predict growth and feed requirements of individual cattle fed in groups based on animal, diet, and environment information (Tedeschi et al., 2006). Evaluations of the CVDS using several databases of finishing cattle were conducted to determine the accuracy and precision of the model in predicted dry matter required (DMR) of pen-fed cattle. As well, the sensitivity of the model’s predictions to deviations from actual ration metabolizable energy (ME) value was conducted. A meta-analysis of growing and finishing steers evaluated to model’s accuracy in predicting DMR of individually fed steers, and the relationships between several model-predicted variables and actual performance and efficiency measures. Results for the first CVDS model evaluation involving pen-fed Santa Gertrudis cattle fed finishing diets revealed that accurate predictions of DMR are possible. The average mean bias for both steers and heifers was 2.43%. The sensitivity analysis of dietary ME values revealed that the model tends to consistently over- and under-predict DMR when the ME values are under- and over-estimated, respectively. However the ranking of pens was not affected by this mis-estimation of diet ME. In the second evaluations, both methods (mean body weight; MBW, dynamic iterative model; DIM) of CVDS were highly accurate and precise in allocating feed to pens of steers fed diverse types of diets and environmental conditions, with both models having a mean bias under 4%. The DIM model was slightly more accurate than the MBW model in predicting DMR. An evaluation of sources of variation revealed that for both models a large portion of the error was random, indicating that further work is needed to account for this variation. The meta-analysis study revealed that the model was able to account for 64% and 67% of the variation in observed dry matter intake (DMI) for growing and finishing steers, respectively. The two model-predicted efficiency measures, the ratio of DMR to average daily gain (ADG) and predicted intake difference (PID), were strongly to moderately correlated with their observed efficiency counterparts. In growing and finishing steers, DMR: ADG was able to account for 76% and 64% of the variation in observed feed conversion ratio (FCR) in growing and finishing studies, respectively. Strong correlations were also found between residual feed intake (RFI) and PID, suggesting that there may also be some similarity on these two measurements.

Graduation date: 1993

Graduation date: 1992

Physiological traits that are biologically associated with feed efficiency may be useful indicator traits residual feed intake (RFI). The objective of this study was to examine the relationships between RFI, temperament, serum hormones and serum metabolites in growing heifers. A 4 yr study (n = 114-119 heifers/yr) was conducted with Brangus heifers (Initial BW = 271 ± 26 kg) that were weaned for 25.5 ± 8.6 d prior to high roughage diet adaptation (ME = 2.0 Mcal/kg DM). Individual dry matter intakes (DMI) were measured using Calan gate feeders and BW measured at 7-d intervals during the 70-d studies. RFI was calculated as the residual from the linear regression of DMI on mid-test BW0.75 and average daily gain (ADG). Temperament scores and exit velocity (EV) were taken at 0-d. Temperament index (TI) was calculated as the average of EV and chute score. On 0-d, blood samples were collected and assayed for partial blood counts (WBC, RBC, hemoglobin, HB), metabolites (total protein, TP; glucose; creatinine; blood urea nitrogen, BUN; β-hydroxybutyrate, BHB) and hormones (cortisol; insulin-like growth hormone I, IGF-I). Across all heifers, RFI was positively correlated with DMI (0.70) and feed:gain (0.59). Heifers with low RFI (< 0.5 SD from mean RFI 0.00 ± 0.71 kg/d) consumed 16 percent less DMI and had 16 percent lower feed:gain than heifers with high RFI (> 0.50 SD from mean RFI). RFI was weakly correlated (P < 0.05) with WBC (0.15), HB (-0.11), total protein (-0.10), BUN (0.10), creatinine (-0.11) and BHB (0.13). Hemoglobin and BHB were weakly correlated with all feed efficiency traits except feed conversion ratio (FCR). No phenotypic correlation was found between cortisol and IGF-I with RFI. Temperament was not correlated with RFI. Cortisol, creatinine and glucose were moderately correlated with all temperament traits. Low TI heifers (calm) had significantly higher Final BW, ADG and DMI than high TI heifers. Calm animals had significantly lower cortisol, HB, creatinine and glucose and higher BHB. These results suggest that the temperament and serum metabolites evaluated in this study have limited utility as indicator traits for RFI in growing heifers.

Three experiments were conducted (1) to develop and characterize polyclonal antibodies against ovine adipocyte plasma membranes (APM), (2) to evaluate the effect of administering the developed antibodies to lambs on lamb growth and carcass characteristics, and (3) to investigate the possibility of using the developed antibodies to identify antigenic components on ovine APM that are tissue, species and possibly site specific. In Experiment 1, the developed antibodies showed a high rate of reactivity to APM and cross reacted with plasma membranes (PM) from liver, kidney, heart and erythrocytes. Adsorption of antisera with either liver PM or erythrocyte PM for 6 h resulted in a significant reduction in antisera cross-reactivity to liver or erythrocyte PM, respectively, with little effect on its specific reactivity to APM or cross-reactivity with PM of the other tissues tested. The antisera also reacted in different affinities to APM from sheep, pig and rat. The antisera also showed differential binding to APM isolated from different anatomical locations. In Experiment 2, five wether lambs were assigned to either a control or treatment group to study the effect of passive immunization with the antisera immunoglobulin (ASig) on lamb growth and carcass characteristics. Treatment with ASig resulted in a significant (P<.OS) reduction of 45% in wet perirenal fat weight, and of 1.8 and 0.8% in subcutaneous and perirenal lipid content, respectively. ASig immunization also significantly (P<.O5) reduced blood plasma non-esterified fatty acid without adversely affecting blood plasma triglycerides or packed cell volumes (hematocrit). Animals immunized with ASig also showed a significant (P<.OS) reduction in average weight daily weight gain, but this effect was not associated with any adverse effect on efficiency of carcass production. Moreover, passive immunization tended to improve protein accretion and efficiency of nitrogen utilization. In Experiment 3, the developed antisera immunoglobulins recognized three unique ovine APM components, in comparison with plazma membranes from liver, kidney, heart or RBC, with molecular weights of 70, 106 and 110 KD, and showed to react more intensely with APM antigenic components that are in common with PM of the tissues tested. Antisera immunoglobulins recognized just two (44, 46 KD) antigenic components on porcine APM that are shared with those of ovine APM but did not react with any component on APM of either rat or chicken. / Graduation date: 1990