A 2-yr study using Mashona- (M, yr 1 and 2) and Tuli-sired (T, yr 2) cows produced from a three-breed diallele cow base comprised of Brahman (BB), Romosinuano (RR), and Angus (AA) was conducted to determine effects of breed type and growing strategies on growth performance and carcass characteristics in early-weaned calves. Steers and heifers used were between 90 and 200 d old at arrival. Cattle were randomly split into one of two nutritional treatment groups with sex, breed type, and age stratified across treatments. Calves were either fed a roughage diet (P) or placed immediately on a concentrate grower diet (F) for approximately x d, then finished together in the feedlot. In both years, F calves gained more (P < .01) than P calves during the growing stage. In yr 1, P calves gained more (P < .05) than F calves during the middle, late and overall finishing period. For yr 2, F calves gained more (P < .05) during the early finishing phase, but P cattle gained more (P < .05) during the middle portion. In yr 1, P calves had higher (P < .05) USDA marbling scores than F calves. Growing program had no effect on carcass characteristics during yr 2. In yr 1, MAA calves gained more (P < .05) during the overall finishing period. TAA calves gained more (P < .01) during the growing stage and TBB calves gained more (P < .05) for the overall finishing period in yr 2. In yr 1, MAA and MBB were fatter (P < .05), and MAA and MAR calves deposited more (P < .01) marbling than others. MAA calves also had less (P < .05) desirable yield grades than other cattle. In yr 2, TAA calves had more (P < .05) marbling than other calves, followed by TRR cattle that deposited more (P < .05) than remaining calves.

A 2-yr study using Mashona- (M, yr 1 and 2) and Tuli-sired (T, yr 2) cows produced from a three-breed diallele cow base comprised of Brahman (BB), Romosinuano (RR), and Angus (AA) was conducted to determine effects of breed type and growing strategies on growth performance and carcass characteristics in early-weaned calves. Steers and heifers used were between 90 and 200 d old at arrival. Cattle were randomly split into one of two nutritional treatment groups with sex, breed type, and age stratified across treatments. Calves were either fed a roughage diet (P) or placed immediately on a concentrate grower diet (F) for approximately x d, then finished together in the feedlot. In both years, F calves gained more (P < .01) than P calves during the growing stage. In yr 1, P calves gained more (P < .05) than F calves during the middle, late and overall finishing period. For yr 2, F calves gained more (P < .05) during the early finishing phase, but P cattle gained more (P < .05) during the middle portion. In yr 1, P calves had higher (P < .05) USDA marbling scores than F calves. Growing program had no effect on carcass characteristics during yr 2. In yr 1, MAA calves gained more (P < .05) during the overall finishing period. TAA calves gained more (P < .01) during the growing stage and TBB calves gained more (P < .05) for the overall finishing period in yr 2. In yr 1, MAA and MBB were fatter (P < .05), and MAA and MAR calves deposited more (P < .01) marbling than others. MAA calves also had less (P < .05) desirable yield grades than other cattle. In yr 2, TAA calves had more (P < .05) marbling than other calves, followed by TRR cattle that deposited more (P < .05) than remaining calves.

Since no effect on CP and diet type on the optimal Trp-to-Lys ratio (TLR) was found in two previous experiments, two extra experiments were planned. In the first one, piglets were fed a Lys-deficient basal diet supplemented with crystalline Lys (to create graded levels of SID Lys). GFR and PUN were measured every 5-d for 15-d; and were analyzed using the broken-line analysis to determine the Lys requirement. As SID Lys level increased, GFR increased linearly and PUN decreased linearly. The SID Lys requirement for was estimated to be 1.02%. To determine the optimal TLR, pigs were fed Trp-deficient basal diet supplemented with crystalline Trp (to create graded levels of SID TLR). Most of the parameters evaluated failed (P > 0.10) to yield an estimate. Based on the evidence we suggest that the optimal SID TLR for early-weaned pigs fed a wheat-barley diet lies below 17.75%.

Since no effect on CP and diet type on the optimal Trp-to-Lys ratio (TLR) was found in two previous experiments, two extra experiments were planned. In the first one, piglets were fed a Lys-deficient basal diet supplemented with crystalline Lys (to create graded levels of SID Lys). GFR and PUN were measured every 5-d for 15-d; and were analyzed using the broken-line analysis to determine the Lys requirement. As SID Lys level increased, GFR increased linearly and PUN decreased linearly. The SID Lys requirement for was estimated to be 1.02%. To determine the optimal TLR, pigs were fed Trp-deficient basal diet supplemented with crystalline Trp (to create graded levels of SID TLR). Most of the parameters evaluated failed (P > 0.10) to yield an estimate. Based on the evidence we suggest that the optimal SID TLR for early-weaned pigs fed a wheat-barley diet lies below 17.75%.

Animal behavior can be used to detect disease and well-being in dairy cattle. In this dissertation, we evaluated the accuracy of an accelerometer to measure step activity, lying time, and lying bouts in pre-weaned dairy calves. The output from the accelerometer was correlated with behavioral measurements taken from video footage. The accelerometer proved to be accurate in identifying step activity (r = 0.99), lying time (r = 0.99), and lying bouts (r = 0.99). The accelerometer was then used to detect behavioral changes occurring around respiratory disease events in pre-weaned calves. Activity declined 1 d prior to clinical disease onset, and this decline persisted for 3 d post-diagnosis. Furthermore, lying bouts declined beginning 2 d prior to diagnosis, and this effect persisted after diagnosis as well. However, aside from a slight reduction in milk intake, feeding behavior was not different between diseased and healthy calves. These data suggest that activity and lying behaviors may be a better measure than feeding behaviors for detection of respiratory disease in pre-weaned dairy calves. Dystocia has detrimental effects on both periparturient dairy cows and newborn calves. We administered a non-steroidal anti-inflammatory drug, meloxicam to periparturient dairy cattle. Treatments included administration prior to calving (MEL-PRE, n = 60), post-calving (MEL-POST, n = 69), or a negative control (CTL, n = 65). We measured the length of labor to determine which cows had easy or difficult calvings. Eutocic MEL-PRE animals produced 6.8 kg/d more milk than eutocic CTL. Regardless of calving difficulty, MEL-PRE animals produced more milk fat, protein, and lactose (kg/d) than the CTL. Additional research is needed to determine appropriate treatments for dystocic calvings. Calves born during the above trial were monitored to determine if meloxicam administration prior to calving impacted newborn calf health and behavior. Calves born difficultly displayed fewer lying bouts for the first few days after birth when compared to calves born easily. No effect of treatment or calving difficulty was noted on calf health. Additional research examining intervention strategies aimed at improving well-being of calves born difficultly is needed. / Ph. D.

The objective of these studies was to evaluate the effect of supplying mannan oligosaccharides (MOS) to pig diets on both weanling pig and sow performances. Nursery pigs challenged with LPS to stimulate an immune challenge had increased body temperature and respiratory rate as well as elevated serum cortisol and TNF-α concentration, MOS-supplemented pigs had a lower rectal temperature and respiratory rate which implied that MOS improves some aspect of the immune function of piglets. MOS supplementation in sow diets during late gestation and lactation had no effect on litter size, but the piglets from MOS-fed sows were heavier at birth (P = 0.04), at weaning (P = 0.03), and during the entire nursery period (P < 0.01). Moreover, milk fat and protein levels as well as the Ig concentrations in milk from MOS-fed sows were numerically higher (2 – 12%; P > 0.10) than control sows. Overall, MOS supplementation in the nursery diet may have limited effects on the growth performance, but may have some beneficial influence on pigs under immune challenge. Furthermore, including MOS to the sow diet during late gestation and lactation can potentially improve piglet body weight as well as growth during the suckling and nursery periods.

Experiments were conducted to determine the optimal conditions for tail-end dehulling of canola meal (CM) and the production of high-protein, high-energy and low-fiber CM. The use of sieves from 250-600µm resulted in the production of dehulled fractions 1 and 2 from three different types of CM. On average, and in comparison with their parent meals, the dehulled fractions 1 and 2 contained less dietary fiber (19.4 and 22.9 vs. 27.5%) and more protein (44.5 and 43.1 vs. 40.1%), respectively. Growth performance experiments were conducted with broiler chickens and weaned piglets fed diets containing dehulled CM fractions. In the broiler chicken trial, no significant differences for feed intake, BWG and feed efficiency were observed, indicating that CM and its low-fiber fractions could replace SBM in the broiler pre-starter diets at a lower cost. In the swine experiment, a beneficial effect of dehulling on final body weight and feed efficiency was observed.

Dois ensaios experimentais foram conduzidos com o objetivo de determinar o efeito dietético da suplementação de acidificantes sobre o desempenho, incidência de diarréia (ensaio 1) e na digestibilidade aparente de nutrientes (ensaio 2). No ensaio 1, com duração de 42 dias, 120 leitões desmamados aos 21 dias foram distribuídos em 8 blocos experimentais com três leitões por baia,foram aplicados cinco tratamentos. Os tratamentos foram: ração sem acidificante, com 1,0% de diformiato de potássio, com 1,0% de ácido fumárico, com 1,0% de ácido cítrico ou com 1,0% de ácido benzóico. No ensaio 2, 10 leitões com peso médio inicial de 16,4 kg foram distribuídos em dois blocos experimentais, cada um com cinco repetições, sob dois tratamentos (ração sem acidificante ou com 1,0% de ácido fumárico). No estudo de desempenho, a adição de ácido fumárico nas rações determinou aumentos (P<0,05) no consumo de ração nos períodos de 0 aos 15 dias, 0 aos 32 dias e ganho de peso de 0 aos 42 dias, quando comparado ao tratamento controle. Não foi observada a ocorrência de diarréia nos leitões nos primeiros 14 dias pós-desmame. No ensaio 2, a adição de 1,0% de ácido fumárico na ração não alterou (P>0,05) os coeficientes de digestibilidade aparente da matéria seca, proteína bruta e fibra bruta, os valores de energia digestível e metabolizável das rações e a taxa de absorção e retenção de nitrogênio. A ausência de diferenças nos coeficientes de digestibilidade aparente dos nutrientes dietéticos com a inclusão do acidificante, provavelmente, deveu-se ao curto período de avaliação. A inclusão de ácido fumárico nas rações de leitões desmamados favoreceu o desempenho dos leitões. / Two experimental assays were conducted in order to evaluate the effect of supplementation of acidifiers in the diets both on performance traits and incidence of diarrhea (assay 1) and on nutrient digestibility (assay 2). In assay 1, which lasted for 42 d, it was used 120 21-days old weaned piglets, distributed in 8 blocks of 3 pigs per pen. There were five evaluated treatments, which consisted of: ration without acidifier, with 1,0% of K-diformate, 1,0% of fumaric acid, 1,0% of citric acid or 1,0% of benzoic acid. In assay 2, 10 pigs with an average weight of 16,4 kg were allocated in two treatments (ration without acidifier or supplemented with 1,0% of fumaric acid) with five replicates each; experimental design was ramdomized complete blocks. In comparison with the control treatment, the addition of fumaric acid in the ration led to an increase in the following parameters: daily feed intake from day 0 to 15 (P< 0,05); daily feed intake and body weight gain from day 0 to 32 (P< 0,05) and from day 0 to 42 d (P< 0,05). There was not treatment effect (P> 0,05) upon feed conversion over the experimental period, and it was not observed the occurrence of diarrhea over the first 14 days after weaning. In assay 2, the addition of 1,0% of fumaric acid in the ration did not modify (P>0,05) the coefficients of apparent fecal digestibility of dry matter, crude protein and crude fiber, the values of digestible and metabolizable energy of the rations and the rates of nitrogen absorption and retention. The absence of differences in the coefficients of the dietary nutrient s apparent digestibilidade with the inclusion of the acidifier, probably, was due to the short evaluation period. The inclusion of fumaric acid in the rations of weaned pigs improved performance of piglets; however, it did not modify the coefficients of apparent fecal digestibility of the nutrients.

This study was an extension of a study submitted in April 2014 by Sheldon D. Holt entitled “Ambient Temperature, Calf Intakes, and Weight Gains on Preweaned Dairy Calves”. A major component in a profitable dairy operation is the raising of female calves as replacement heifers; but since no direct income is generated by calf raising alone, it is often overlooked as a potential profit area on a dairy farm. Calf management practices that ultimately impact milk productivity and reproductive performance during a heifer’s lifetime begin at birth. This study examines the effect of calf starter intake on calf growth, measuring specifically calf weight. How calf starter intake affected production costs was also examined. Other factors included in the study were seasonal change, hip height, days since birth, and weather conditions. The cost of calf starter is one of the main contributors to total production cost in raising dairy calves. Since the amount of starter intake consumed by the calves in this study was measured by Holt, a cost analysis can be performed using these data. Therefore, the first two objectives of this study are to 1) develop a model which minimizes cost of starter feed (which is a variable controlled by the dairy producer) and 2) use the model developed under objective 1) to find the breakeven point (where the cost of an input is less than or equal to the value gained from that input) and conduct sensitivity analysis with respect to this point. Although an analysis was performed on the data at the close of its collection in 2014 by S.D Holt, there are several econometric issues that were not adequately addressed before these analyses were performed. The following problems have been found in the data: functional form, multicollinearity, heteroskedasticity, and serial correlation. Any interpretation or prediction based on these data, without these issues being resolved, is not reliable. In order for interpretations and predictions based on these data to be valid, the last two objectives of this study are to 3) define in detail the econometric problems that existed in Holt’s study and 4) find and implement solutions to econometric problems that existed in that study.

Post-weaning diarrhea is a major health challenge in the swine industry and is routinely managed by fortifying pig starter diets with antimicrobials. But there are concerns about antibiotic resistance, hence the need for identifying effective alternatives. The use of spray-dried whole egg powder containing anti-F4 antibodies (SDWE) against recombinant F4 antigens and chitosan oligosaccharide and Enterococcus fecalis probiotic combination (CPRO) was investigated in two trials using enterotoxigenic Escherichia coli K88+ (ETEC) oral challenge model in 21-d-old piglets. Pre-challenge, SDWE supported higher (P < 0.05) piglet performance whereas during the post-challenge period, SDWE and CPRO had no effect on growth performance but diarrhea incidences and severity were reduced (P > 0.05) in SDWE-fed piglets compared to the control. The results show that SDWE supported greater piglet performance pre-ETEC challenge although there was no benefit of SDWE or CPRO supplementation evident during the post-challenge period in early-weaned pigs. / October 2015