The growth performance of Angus-Polled Hereford F₁ calves was compared to the expected progeny differences (EPD) estimated by the American Polled Hereford Association to evaluate the usefulness of EPD estimates for improving commercial beef production. Polled Hereford sires were selected from the high accuracy sires listed in the American Polled Hereford Association's sire summary. Four types of sires were used: 1) Sires with high yearling weight and high maternal EPD's; 2) Sires with high yearling weight and low maternal EPDâ s; 3) Sires with low yearling weight and high maternal EPD's; and 4) Sires with low yearling weight and low maternal EPD's. The resulting progeny were weighed at birth, approximately 135 d, weaning and approximately 1 yr. Hip heights were also measured at weaning. Linear regressions of progeny performance on EPD indicated that birth and yearling weights were accurately predicted by their respective EPD estimates. Weight and height at weaning were not accurately predicted by weaning weight EPD. Partial regressions of progeny performance on yearling weight and maternal EPD's were also calculated. Regression of progeny performance on yearling weight EPD resulted in .16 ±.09 kg/kg for 135-d weight, .28 ± .09 kg/kg for weaning weight, .073 ± .020 cm/kg for weaning hip height and .93 ±.19 kg/kg for yearling weight. Comparable regression values for maternal EPD were .44 ± .18 kg/kg, .31 ± .17 kg/kg, .100 ± .040 cm/kg and .22 ± .36 kg/kg for 135-d, weaning weight, weaning hip height and yearling weight, respectively. These results indicate that maternal EPD values predicted some differences in preweaning growth that were not predicted by yearling weight EPD. The progeny performance data was also used to calculate independent EPD estimates for birthweight, weaning weight, and yearling weight. Correlations between these EPD estimates and those made by the American Polled Hereford Association were .49 for birthweight, .26 for weaning weight and .66 for yearling weight. The low correlation between weaning weight EPD estimates was significantly below expectation and indicates that the American Polled Hereford Association estimates were inadequate for predicting preweaning growth differences in these crossbred calves. / Master of Science

The effect of feeding colostrum or milk to newborn calves on serum cortisol, thyroxine and immunoglobulin G was investigated. Twenty-four calves (12 males and 12 females) were obtained immediately postpartum and randomly assigned to one of two rations after being blocked by breed and sex. Both rations were force-fed at birth, 12, 24 and 36 h postpartum. Blood sampling was performed at 0 time, 1, 2, 3, 4, 6 and 12 h postfeeding with this regime followed for a 48 h period (4 feedings). The average serum cortisol concentration was highest at birth, 221.9 and 245.6 ng/ml for colostrum and milk-fed calves, respectively. Cortisol levels between treatments were different (P<.05) at 2, 3, 12, 14, 18, 24, 37 and 48 h postpartum. The sex of the calf did not affect the mean cortisol concentrations. No treatment difference was observed for serum thyroxine. A sex difference was observed with the female calves exhibiting higher average thyroxine concentrations over the entire trial. A reduction in thyroxine concentration occurred with time (P<.001) as mean concentrations peaked at 4 h postpartum (22.1 μg/dl) and declined to 10.6 μg/dl by 48 h postpartum. Both treatment groups were born with similar serum immunoglobulin G levels (~0.7 mg/ml). However, at approximately 4 h postpartum, the colostrum-fed calves acquired an increase (P<.001) in serum immunoglobulin G, peaking at 24 h postpartum (26.83 mg/ml) and remaining much higher throughout the entire trial. There was a treatment difference (P<.001) between the two groups following the 4 h sample. Muscle samples (20-30g) were surgically removed from the right semitendinosus at 36 h postpartum from 14 neonatal beef calves (male and female), homogenized, and centrifuged at 105,000 x g at 4 C for 60 min. The supernatant (cytosol) was harvested and receptor quantitation, binding kinetics and ligand specificity assays were performed via [1,2,4,³H] dexamethasone. There were no binding differences between the colostrum and milk-fed calves' muscle samples. The average protein content of the muscle cytosol fraction was 50.82 mg/ml. The binding component displayed a high apparent equilibrium dissociation constant for the binding of [³H] dexamethasone (K_d = 2.34x10 ⁻⁸ ). The apparent maximum number of binding sites determined from Scatchard plots was approximately 37.61 fmol/mg of protein in the case of the dexamethasone receptor. Maximum binding appeared to reached between 16 and 24 h (48.5 and 48.2 %, respectively). Competition assays indicated all of the ligands tested had an affinity for the glucocorticoid receptor. The percent of specific binding for each was: dexamethasone (66+/-14), corticosterone (52+/-10), cortisol (58+/-13), estradiol-17, beta (37+/-7), progesterone (29+/-9), testosterone (10+/-3), and triamcinolone (41+/-11). / Master of Science

Three commercially prepared rumen cultures and fresh rumen liquor were compared to determine their effect on the rate of gain and efficiency of feed utilization of a) twenty-four steer calves, b) twenty-four two-year old steers in pasture, and c) twelve weanling lambs. Two of the cultures were prepared from the rumen contents of fast and slow gaining steers from experimental feeding tests, the other was a commercial product marketed under the trade name of Ruzyme. / Master of Science

M. S.

Peptide, plasma free, erythrocyte free and serum protein amino acid arteriovenous differences were quantified across the gastrointestinal tract (GIT) and liver of growing calves during a "steady state" and fasting metabolism. Six Holstein steer calves (136 kg) surgically equipped with cannulae in the aorta, portal vein and hepatic vein were maintained under constant light and fed a natural diet as 24 hourly meals per day. Blood was obtained simultaneously from all cannulae at 9 to 12 d postsurgery during the midpoint of a 1-hr feeding interval and following a 72-hr fast. Most amino acids were added to plasma by the GIT but fasting reduced the magnitude of this addition. GLN and GLU were the only plasma amino acids removed by the GIT. The liver removed a large portion of amino acids in portal plasma but a net splanchnic plasma free amino acid output occurred. Hepatic removal of amino acids, particularly VAL, ILE and LEU, increased after fasting. The GIT generally removed amino acids from the erythrocyte while the liver contributed amino acids to this pool. Peptide amino acids increased as blood crossed the GIT. Responses paralleled those of plasma free amino acids in direction but were threefold greater for peptide amino acids. A net output of peptide amino acids from the splanchnic bed was observed. Generally amino acids were added to the primarily globulin, albumin and mixed protein serum fractions while the pure albumin fraction contributed amino acids to the GIT. Fasting reversed the direction of response in the four fractions monitored. Arteriovenous differences for amino acids in two largely albumin fractions responded oppositely indicating a potential transport role of other proteins in these fractions. A more variable response was observed across the liver with direction and magnitude dependent upon individual amino acids. Fasting resulted in a release of amino acids by the liver into all four fractions. Several blood pools appear to be involved in the interorgan transport of amino acids. The extent and direction of transport varies with tissue, blood pool, nutritional status and amino acid. Quantitatively, peptides appear to be highly involved in interorgan movement of amino acids. / Ph. D.

Antibiotics are routinely used in modern livestock production systems to treat and prevent disease as well as to enhance livestock production and/or outputs. This widespread use of antibiotics has led to a growing worldwide interest in antibioticfree animal production. The addition of feed supplements such as nucleotides to improve intestinal health as well as the early development of the immune system needs to be investigated as an environmentally-friendly nutritional management activity. In this study four (4) groups of newborn Holstein calves (n=24) were evaluated after being treated as follows: Group 1 (Negative control), Group 2 (Investigational Veterinary Product (IVP) 1 – Oral supplement containing nucleotides, vitamins, essential fatty acids, essential amino acids, pre-biotics and trace-minerals), Group 3 (IVP 2 – Oral supplement containing nucleotides only at concentration and dosage equal to IVP1) and Group 4 (IVP 3 - Parenteral glucocorticoids). Results of the study indicated that: Pre-colostral Serum IgG titres – After titration of the serum the anti-BVDV results showed no difference between the study groups. All calves recorded a SP ratio of zero value (0.00 ± 0.2) indicating that they had not been nursed by their mothers prior to the start of the study. This was an entrance requirement for the calves to be enrolled into the study. Apparent Efficiency of Absorption % (AEA%) – Literature shows that an AEA% result of between 20%-30% is good and 35% is excellent. The AEA% recorded for this study fell within this range although there was no statistically significant difference shown between the groups. In spite of a strictly controlled study protocol, 7 of the 24 calves (29%) still suffered from FPT in this study. The result falls within the range of 19% - 37% reported on United States of America (USA) farms by Doepel and Bartier in 2014. Serum cortisol - When compared to the control group, there were no statistical significant difference evident for group 2 and group 3. However, the difference between the Glucocorticoid – Group 4 and the control and other groups was statistically significant (P = 0.0001; table 12) at the various time intervals. It was also evident that the inclusion of parenteral glucocorticoids (group 4) may have assisted in prolonging the natural “gut closure”. Gut closure – a positive 2 point linear regression forecast line indicated an increasing trend in IgG absorption post-24 hours for group number 4 whilst groups 1, 2 and 3 each had a negative 2 point linear regression forecast line (figure 23). Weight / ADG (D42) - Group 2 showed a statistically significant increase in mean D42 weight (P = 0.0042) of 59.167 kg ± 3.545 kg when compared to the other study groups and compared to the control group (P = 0.0227). A comparison of the relative increase in mass of groups indicated that Group 2 efficiently achieved this result with a statistically significant ADG of 0.536 kg (P = 0.014) compared to the other study groups and compared to the control group (P = 0.022). In addition, weight / FCR – FCR was calculated for all groups as follows: G1 – 4.000 kg, G2 - 2.593 kg, G3 – 2.703 kg and G4 - 3.012 kg feed required for the production of 1 kg meat. The results indicated that the group 2 feed input was the most economical followed by groups 3, 4 and control respectively. In conclusion, it is evident that a nutritional supplement containing nucleotides, vitamins, trace- minerals, essential fatty acids, essential amino acids and pre-biotics may contribute significantly to important economic indicators such as weight gain, ADG and FCR on a commercial dairy farm. / Environmental Sciences / Ph. D. (Environmental Science)

Antibiotics are routinely used in modern livestock production systems to treat and prevent disease as well as to enhance livestock production and/or outputs. This widespread use of antibiotics has led to a growing worldwide interest in antibioticfree animal production. The addition of feed supplements such as nucleotides to improve intestinal health as well as the early development of the immune system needs to be investigated as an environmentally-friendly nutritional management activity. In this study four (4) groups of newborn Holstein calves (n=24) were evaluated after being treated as follows: Group 1 (Negative control), Group 2 (Investigational Veterinary Product (IVP) 1 – Oral supplement containing nucleotides, vitamins, essential fatty acids, essential amino acids, pre-biotics and trace-minerals), Group 3 (IVP 2 – Oral supplement containing nucleotides only at concentration and dosage equal to IVP1) and Group 4 (IVP 3 - Parenteral glucocorticoids). Results of the study indicated that: Pre-colostral Serum IgG titres – After titration of the serum the anti-BVDV results showed no difference between the study groups. All calves recorded a SP ratio of zero value (0.00 ± 0.2) indicating that they had not been nursed by their mothers prior to the start of the study. This was an entrance requirement for the calves to be enrolled into the study. Apparent Efficiency of Absorption % (AEA%) – Literature shows that an AEA% result of between 20%-30% is good and 35% is excellent. The AEA% recorded for this study fell within this range although there was no statistically significant difference shown between the groups. In spite of a strictly controlled study protocol, 7 of the 24 calves (29%) still suffered from FPT in this study. The result falls within the range of 19% - 37% reported on United States of America (USA) farms by Doepel and Bartier in 2014. Serum cortisol - When compared to the control group, there were no statistical significant difference evident for group 2 and group 3. However, the difference between the Glucocorticoid – Group 4 and the control and other groups was statistically significant (P = 0.0001; table 12) at the various time intervals. It was also evident that the inclusion of parenteral glucocorticoids (group 4) may have assisted in prolonging the natural “gut closure”. Gut closure – a positive 2 point linear regression forecast line indicated an increasing trend in IgG absorption post-24 hours for group number 4 whilst groups 1, 2 and 3 each had a negative 2 point linear regression forecast line (figure 23). Weight / ADG (D42) - Group 2 showed a statistically significant increase in mean D42 weight (P = 0.0042) of 59.167 kg ± 3.545 kg when compared to the other study groups and compared to the control group (P = 0.0227). A comparison of the relative increase in mass of groups indicated that Group 2 efficiently achieved this result with a statistically significant ADG of 0.536 kg (P = 0.014) compared to the other study groups and compared to the control group (P = 0.022). In addition, weight / FCR – FCR was calculated for all groups as follows: G1 – 4.000 kg, G2 - 2.593 kg, G3 – 2.703 kg and G4 - 3.012 kg feed required for the production of 1 kg meat. The results indicated that the group 2 feed input was the most economical followed by groups 3, 4 and control respectively. In conclusion, it is evident that a nutritional supplement containing nucleotides, vitamins, trace- minerals, essential fatty acids, essential amino acids and pre-biotics may contribute significantly to important economic indicators such as weight gain, ADG and FCR on a commercial dairy farm. / Environmental Sciences / Ph. D. (Environmental Science)

Made available in DSpace on 2015-03-26T13:55:18Z (GMT). No. of bitstreams: 1 texto completo.pdf: 594941 bytes, checksum: 481295e25f8fd2172623ece0c377ba7e (MD5) Previous issue date: 2013-03-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this work was to evaluate the nutritional requirements of protein and minerals for maintenance and growth of Holstein calves from birth to 87 days old. Forty-two male Holstein calves with 3 days old and 35.56 ± 5.86 kg of initial body weight were used. Ten references animals were randomly slaughtered on the 4th day of the feeding trial. The remaining animals were allocated into 4 treatments (2.0; 4.0; 6.0; 8.0 kg/day of milk). All animals were fed with concentrate starter ad libitum throughout the experiment. From eight animals per treatment, four were slaughtered at 59 days old, while the other four were weaned at the same age and milk exchanged for Coast-cross (Cynodon spp.) hay ad libitum, they were slaughtered at 87 days of age. Three digestibility assays were conducted at the average ages of 17, 42 and 75 days in four animals per treatment, to estimate the digestible nutrients, when feces samples were collected for 24 hours. Milk, concentrate starter and hay samples were collected weekly. At the end of the experiment the animals were slaughtered for quantification of empty body weight (EBW) and body composition. The predicted equations for total dry matter intake (DMITotal) and dry matter intake of milk (DMIMilk) for suckling calves Holstein, according to average daily gain (ADG) and body weight (BW), were respectively: DMITotal= 0,061±0,074 + 0,549±0,072 × DMIMilk + 0,188±0,087 × ADG + 0,006±0,002 × BW and DMIMilk = 1,382 + 2,750 × ADG &#8210; 0,039 × BW. There wasn t any quadratic effect on the amount of milk ingested on intake of dry matter (DMI) (P = 0.656), crude protein (CP) (P = 0.646), ether extract (EE) (P = 0.418) and total carbohydrates (TC) (P = 0.827). However, there was a linear effect of the quantity of milk (P < 0.01) on the consumption of these in the period between 4 and 59 days. During post-weaning wasn t any linear and quadratic effects of the volume of milk on the DM, CP, EE, and TC, which in this period averages, respectively: 1.767, 0.336, 0.026 and 1.365 kg / day. However, the milk had a linear effect on DMI digestibility and nutrient (P < 0.01) during 4-59 days of age, no differences in these variables in the post-weaning period. The average digestibility of DMI, CP, EE, and TC during the period 60-87 days were, respectively: 84.29, 83.98, 77.19 and 87.83%. The average daily gain (ADG, P = 0.885), gain of empty body weight (EBW, P = 0.794), carcass weight gain (CWG, P = 0.950), warm carcass yield (WCY) and cold carcass yield (CCY) weren t influenced by the quadratic effect of the amount of milk intake during lactation was observed only linear effect (P < 0.01) the amount of milk ingested. During post-weaning weren t observed linear and quadratic effects on these variables, these animals showed average 0.807 kg / day for ADG; 0.510 kg / day for EBW; 0.331 kg / day for CWG; 0.497 kg / day for WCY and 0.510 kg / day for CCY. When assessed ADG, EBW and CWG for the period 4-87 days of life of animals (average), it was observed that these variables were influenced only by the linear effect of the amount of milk provided (P < 0.01). The efficiency of utilization of metabolizable energy for maintenance (km) and gain (kg) were 59.91 and 41.46%, respectively. We conclude that the requirements NEm and MEm Holstein suckling calves are 78.6 and 131.2 kcal/EBW0,75/day and NEg can be obtained by the equation: NEg (Mcal / kg EBW / day) = 1,039 × EBW0,094. / O presente trabalho foi desenvolvido com intuito de avaliar o efeito do volume de leite fornecido sobre o consumo de nutrientes e exigências de energia em bezerros lactentes. Foram utilizados 42 bezerros machos, da raça Holandesa, com idade inicial de 3 dias e peso corporal médio inicial de 35,56 ± 5,86 kg, os quais foram distribuídos em delineamento inteiramente casualizado (DIC) em quatro tratamentos, constituídos de diferentes quantidades de leite. Dez animais foram aleatoriamente selecionados para compor o grupo referência, sendo abatidos após o nascimento, com 3 dias de idade. Os animais remanescentes foram aleitados até atingirem 58 dias de vida. Os tratamentos foram: 2,0; 4,0; 6,0 e 8,0 litros de leite/dia, fornecidos em duas refeições, e ração concentrada oferecida ad libitum comum aos animais de todos os tratamentos. Cada tratamento foi avaliado em 8 animais, sendo que, desses 4 foram abatidos aos 59 dias e 4 passaram a receber feno de Coast cross (Cynodon dactylon) ad libitum, mais ração concentrada e, posteriormente, abatidos aos 87 dias de vida. Para avaliação da digestibilidade das dietas, foram realizadas coletas totais de fezes nas idades médias de 17, 42 e 75 dias de vida, compreendendo 24 horas de coleta. Ao final do experimento os animais foram abatidos para quantificação do peso de corpo vazio (PCVZ) e da composição química corporal. As equações preditas para CMSTotal e CMSLeite para bezerros lactentes da raça Holandesa, foram respectivamente: CMSTotal = 0,061±0,074 + 0,549±0,072 × CMSLeite + 0,188±0,087 × GMD + 0,006±0,002 × PV e CMSLeite = 1,382 + 2,750 × GMD &#8210; 0,039 × PV, onde: CMSTotal é o consumo de matéria seca total (kg/dia); CMSLeite é o consumo de matéria seca proveniente do leite (kg/dia), GMD é o ganho médio diário (kg/dia), PV é o peso vivo (kg). Não foi observado efeito quadrático da quantidade de leite ingerida sobre os consumos de matéria seca (MS) (P = 0,656), proteína bruta (PB) (P = 0,646), extrato etéreo (EE) (P = 0,418) e carboidratos totais (CHOT) (P = 0,827). Entretanto, verificou-se efeito linear da quantidade de leite (P < 0,01) sobre o consumo esses no período de 4 a 59 dias de vida. No pós-desmame não ocorreu os efeitos quadrático e linear do volume de leite sobre os consumos de MS, PB, EE e CHOT, que nesse período médias de, respectivamente: 1,767; 0,336; 0,026 e 1,365 kg/dia. A digestibilidade da MS (P = 0,665) e dos nutrientes, PB (P = 0,902), EE (P = 0,944) e CHOT (P = 0,889) não foram influenciadas pelo efeito quadrático da quantidade de leite ingerida. Todavia, o leite teve efeito linear sobre a digestibilidade da MS e dos nutrientes (P < 0,01) no período de 4 a 59 dias de vida, não sendo observadas diferenças nessas variáveis no período pós-desmama. A digestibilidades médias da MS, PB, EE e CHOT durante o período de 60 a 87 dias foram, respectivamente: 84,29; 83,98; 77,19 e 87,83%. O ganho médio diário (GMD, P = 0,885), ganho de peso de corpo vazio (GPCVZ, P = 0,794), ganho de peso da carcaça (GPCAR P = 0,950), rendimento de carcaça quente (RCq) e rendimento de carcaça frio (RCf) não foram influenciadas pelo efeito quadrático da quantidade de leite ingerida durante o aleitamento, sendo observado somente efeito linear (P < 0,01) da quantidade de leite ingerida. No pós-desmame não foram observados efeitos quadrático e linear sobre essas variáveis, esses animais apresentaram médias de 0,807 kg/dia para GMD; 0,510 kg/dia para GPCVZ; 0,331 kg/dia para GPCAR; 0,497 kg/dia para RCq e 0,510 kg/dia para RCf. Quando avaliado o GMD, GPCVZ e GPCAR para o período de 4 a 87 dias de vida dos animais (médio), observou-se que essas variáveis foram influenciadas somente pelo efeito linear da quantidade de leite fornecida (P < 0,01). As eficiências de utilização da energia metabolizável para mantença (km) e para ganho (kg) foram de 59,91 e 41,46%, respectivamente. Conclui-se que as exigências de ELm e EMm para bezerros lactentes da raça Holandesa são de 78,6 e 131,2 kcal/PCVZ0,75/dia e que ELg pode ser obtidas pela equação alométrica: ELg (Mcal / kg PCVZ /dia) = 1,039 × PCVZ0,094.

An immunoglobulin-fortified milk replacer and a subcutaneous (SC) injectable solution of immunoglobulins (Ig) were examined as methods of achieving passive immunity in neonatal calves. Bovine Ig, from abattoir blood, were purified by polyphosphate fractionation and ion-exchange chromatography. In experiment 1, carried out at Agriculture Canada Research Station, Agassiz, 37 colostrum-deprived Holstein-Friesian bull calves were allotted to one of four treatments. Col/WM calves were fed colostrum on day 1 and whole milk, days 2 - 42. MR-Nolg calves (control) were fed milk replacer with no Ig, days 1-42. MR-Hi/Lo calves were fed milk replacer with Ig at 50 mg/ml on day 1, and at 10 mg/ml, days 2 -21. MR-Hi/No calves were fed milk replacer with Ig at 50 mg/ml, day 1,'and with no Ig, days 2 - 21. From days 2 2 - 42, MR-Hi/Lo and MR-Hi/No treatment calves received milk replacer with no Ig. In experiment 2, carried out at the University Research Farm at Oyster River, 24 colostrum-deprived Holstein-Friesian bull calves were allotted to one of three treatments. The first two treatments were the same as for experiment 1, Col/WM and MR-Nolg fed for days 1-21. MR-Lo Inj calves were fed milk replacer with Ig at 10 mg/ml, days 1-21, and were also given a SC injection of Ig solution within the first 6 hours of life. For days 2-42, calves were fed WM or MR-Nolg, as per experiment 1. For both experiments, blood samples and calf weights were taken at birth, 24 & 48 hours of age, day 7 and weekly thereafter for six weeks. Diarrhea (scours) levels, rectal temperatures and general health of calves were recorded daily for the first three weeks as well. Experiment 1 survival at 6 weeks of age was 11 out of 11 calves for Col/WM treatment, 8 out of 8 calves for MR-Hi/Lo treatment, 7 out of 8 calves for MR-Hi/No and a significantly lower (P>0.05) 7 out of 9 calves for MR-Nolg. In experiment 2, survival was 7 out of 8 calves for both Col/WM and MR-Lo-Inj treatments and a significantly lower (P>0.05) 4 out of 8 calves for MR-Nolg treatment. Calves on MR-Hi/No had significantly higher diarrhea levels than the other three treatments over weeks one and four in experiment 1. In experiment 2, calves which did not receive any Ig had significantly higher diarrhea levels over weeks three and four than calves which received Ig. Experiment 1 average daily gains (ADG) were significantly higher for calves on Col/WM, MR-Hi/Lo and MR-Hi/No treatments than for calves on MR-Nolg at six weeks of age. In experiment 2, six week ADG were significantly higher for calves on Col/WM and MR-Lo Inj treatments than for MR-Nolg. For both experiments, serum Ig levels of calves on Col/WM were significantly higher than calves on the other treatments at 24 and 48 hours of age. MR-Hi/Lo, MR-Hi/No and MR-Lo Inj calves trended to higher serum Ig levels than MR-Nolg calves but were not significantly different. Calves which received Ig, from colostrum, the Ig-fortified milk replacer or a subcutaneous Ig injection, had higher survival rates, lower diarrhea levels, less antibiotic treatment and higher average daily gains than calves hot receiving any Ig. It was concluded that immunoglobulins, administered either orally or parenterally, are an effective, alternative method, for providing passive immunity in neonatal calves. / Land and Food Systems, Faculty of / Graduate

Call number: LD2668 .T4 1986 N44 / Master of Science / Agricultural Economics