Academic literature on the topic 'Heifer calves'

Whether they are planning to calve for the first time at two or three years old Many farmers choose to serve their maiden dairy heifers (animals not previously served, (M. A. F. F. 1985)) with a beef breed recognised for giving easier calvings .Often the heifer breeding programme is not well supervised and it is a matter of convienience to use a resident beef bull.There are however,considerable advantages to serving heifers with dairy bulls including an increased number of heifer calves for selection or the ability to serve older, nature cows (animals that have commenced at least their first lactation (M. A. F. F. 1985))with a continental beef breed giving large calves of higher market value. Because heifers tend to be calved as a group they provide a batch of calves which can be concentrated upon, easing management and improving control over performance.If heifers are served by bulls of as higher genetic merit as would normally be used on cows then increased genetic turnover will raise the genetic index in the younger dam which should be reflected in her daughter’s performance.

Proxies for feed efficiency, such as blood-based indicators, applicable across heifers varying in genetic makeup and developmental state are needed. Assessments of blood analytes and performance were made in heifer calves and pregnant heifers. Residual feed intake, a measure of feed efficiency, was used to categorize each population of heifers as either efficient or inefficient. Efficient heifer calves had lower mean cell hemoglobin, greater lymphocyte count, and fewer segmented neutrophils at the end of the test compared to inefficient calves. Efficient pregnant heifers had greater counts of lymphocytes with fewer segmented neutrophils at the end than inefficient pregnant heifers. Efficient heifer calves exhibited higher specific immunoglobulin M than inefficient calves. Throughout the test, efficient heifer calves had elevated potassium and phosphorus, and reduced alkaline phosphatase (ALP) compared to inefficient heifers. Efficient pregnant heifers showed greater ALP, non-esterified fatty acids and creatinine, but lower cholesterol and globulin than inefficient pregnant heifers. Levels of red and white blood cells, creatine kinase, cholesterol, glucose, potassium and phosphorus were higher in heifer calves compared with pregnant heifers. There is potential for blood analytes as proxies for feed efficiency; however, it is necessary to consider the inherent associations with feed efficiency and heifers’ developmental stage.

Using Missouri Show-Me-Select Replacement Heifers Inc. sale data, this article uses hedonic modeling to assess the marginal implicit values of physical and genetic characteristics, expected performance characteristics of calves, and market factors to bred heifer price. In 2008, a higher quality standard, known as Tier II, was created combining minimum expected progeny difference (EPD) accuracies for a heifer's sire with previous heifer standards. Heifer characteristics and market factors as well as yearling and carcass weight EPDs were found to significantly influence heifer price. Results suggest that Tier II heifers receive a premium compared with traditional Show-Me-Select heifers.

Dairy heifers in New Zealand are typically naturally mated by Jersey bulls to produce low-value non-replacement offspring sold for slaughter a few days after birth. Producing a beef-sired calf from a dairy heifer will increase the value of these calves for beef production but may compromise the subsequent career of the animals, in terms of milk production, rebreeding success, health, or survival of the heifer. This study aimed to determine the impact of low birthweight Angus and Hereford bulls versus breed-average Jersey bulls on the reproduction and production traits of first-calving dairy heifers. The experiment included 304 heifer-calf pairs over 2 years. Calves sired by Angus and Hereford bulls were 3.5–4.4 kg and 3.7–6.8 kg heavier than Jersey-sired calves and had a 4.2% and 9.3% incidence of assistance at birth for normally presented calves over the 2 years, respectively. No normally presented Jersey-sired calves were assisted. There was no difference in body condition score, pre-calving live weight, milk production, pregnancy rate, inter-calving interval, re-calving day, and 21-day re-calving rate of heifers mated to the different breeds of bulls. The results indicate that the Angus and Hereford bulls with low birthweight and high direct calving ease estimated breeding values (EBV) can be used to produce calves of greater value than Jersey-sired calves without impacting dairy heifer production. However, a small increase in assistance at calving could be expected.

The national cow herd consists of 1.64m dairy and 0.43m beef cows. They produce a total of 1.76m reared calves annually. Of these 0.42m heifers go as herd replacements, leaving 0.46m heifers and 0.88m males available for beef production. There is a 2:l ratio of males to femaies in the population of calves available for beef production. Also, there are few straightbred dairy heifer calves available and the mean birth date of heifer calves for beef production is later than that cf males. The objectives of the present experiment were (i) to compare the performance and carcass composition of non-implanted and implanted heifers and steers and (ii) to compare the carcass composition of serially slaughtered non-implanted and implanted heifers.Sixty tour (48 female and 16 male) Spring born Hereford x Friesian calves (initial live-weight 45 kg) were purchased and reared on milk replacer and concentrates. After 81 days they were blocked on weight and assigned from within sex type to 8 treatment groups.

A total of 120 crossbred heifers (initial weight = 270 ± 3 kg) were used in a project to evaluate a once-calved-heifer system of beef production. They were reared on a cereal silage–grain diet and, beginning at an average age of 385 d, exposed during a 6-wk breeding period to bulls of breeds chosen for calving ease. Ninety-six heifers reared calves to weaning. The calves were weaned and the heifers were slaughtered 3, 5 or 7 mo after calving, and the feed conversion efficiency of these treatment groups was compared with that of a similar group of 32 heifers slaughtered at 457 d of age after a conventional feeding program. Feed conversion calculations included the combined cow–calf unit for heifers that had reared a calf and were based on weaning-day and end-of-test (27 Sept.) endpoints. During the post-calving period, the late-weaned cow–calf units tended to be more efficient to the point of weaning, but the early-weaned ones were significantly more efficient if the calf's performance from weaning to the end of test was considered. From the start of test to the weaning endpoint, conventionally reared heifers were significantly more efficient than early-weaned once-calved heifers on many of the bases studied. To the end-of-test endpoint, however, they did not differ significantly (e.g., 411.4 ± 20.5, vs. 402.1 ± 29.0, 441.0 ± 29.0 and 460.2 ± 29.0 MJ DE kg−1 lean product weight for conventionally reared vs. 3-, 5- and 7-mo-weaned once-calved heifers). These results suggest that animals in a once-calved-heifer system of beef production can utilize digestible energy as efficiently as those in a conventional system if conception failure and calf losses can be controlled. Key words: Beef production, heifers once-calved, feed efficiency

Major changes are taking place in the UK beef industry, as a result of the reduction in dairy cow numbers due to milk quotas. Similar reductions are taking place throughout Europe and have resulted in a strong export market for UK calves. Consequently in 1988 there were 800,000 fewer calves available for beef production than there were when quotas were introduced. This downward trend is forecast to continue and by 1990 the EEC will no longer be self-sufficient for veal and beef.At times of calf shortages the concept of once-bred heifer beef (producing one calf out of a heifer otherwise destined for slaughter as clean beef, and then slaughtering her shortly after calving) has been considered as a way of generating extra calves and meeting the shortfall. Historically low fertility in young heifers, and high levels of dystokia have limited the commercial uptake of the technique. In addition returns have been low because heifers that have produced a calf are not eligible for Variable Beef Premium payments and, being unfamiliar with this type of slaughter animal the meat trade has regarded tham as cull cows and paid a reduced price.

For those involved in suckler cattle systems, there are likely to be several new opportunities for increasing production efficiency in the years ahead. As a result of recent developments in embryo production technology the future is likely to see embryo transfer being used on an increasing scale and eventually taking over from artificial insemination as a major factor influencing the production of beef calves. Sex control techniques, applied to sperm or to embryos, are likely to be of particular value in making bull calves available for twinning or heifer calves for once-bred heifer production systems. The paper examines the various possibilities for applying reproductive technology in enhancing fertility, controlling oestrus and ovulation, inducing twin births, increasing the efficiency of once-calved heifer production systems,in the application of cloning techniques and the use of recombinant DNA technology.

In a national survey of US dairy operations, 1685 dairy operations reported 47057 new dairy heifers (either births or acquisitions) and 4427 deaths (9·4%) of preweaned dairy heifer calves over a 3 month period. Stepwise logistic regression was used to identify management practices associated with high mortality among preweaned heifers in dairy operations where at least three dairy heifer calves were born alive or moved on to the operation. Analysis was done twice: once by separating all operations by size into high or low mortality; again using only operations with <2 and >10% mortality to eliminate dairy operations with intermediate levels of mortality from the comparisons. Results were similar. Dairy operations in the West were more likely to fall in the high mortality category than dairy operations in the rest of the country. In addition, the following dairy operation characteristics were associated with high death levels in both models: rolling herd average milk production <7710 kg, preweaned heifers placed in groups of seven or more, a male having primary responsibility for the care and feeding of preweaned heifers, calves not receiving hay or other roughages until >20 d old, calves fed on mastitic or antibiotic milk after colostrum and calves not given whole milk after colostrum.

In seasonal block calving herds reproductive efficiency can have a significant impact on productivity and profitability. Within this it is key that the nulliparous heifers calve down promptly in the block, and if these heifers can have heifer calves it will expediate genetic gain. There is extensive research into the conception rates of differing protocols and the literature is reviewed to support the choice of protocol used in the subsequent case study. The case study uses a 6-day progesterone protocol with two injections of prostaglandin F2α and sexed semen; it demonstrated acceptable conception rates as well as the variability that can occur between different bulls' semen straws. Finally, the case study assesses the costs and benefits of the synchronisation programme and concludes a cost benefit of £88.55 per heifer.

This study was to evaluate effects of milk replacer (MR) composition on: mass and composition of mammary parenchyma (PAR) and fat pad (MFP), growth hormone (GH)/insulin-like growth factor-I (IGF-I) axis gene expression, and putative mammary epithelial stem cells. The hypothesis was that diet during the pre-weaning period alters the development, persistence, or activity of populations of putative mammary epithelial stem cells, possibly through involvement of GH/IGF-I axis molecules. Twenty-four newborn heifers were fed one of four MR diets: CON (20% CP, 21% fat MR fed at 441 g DM/d), HPLF (28% CP, 20% fat MR fed at 951 g DM/d), HPHF (27% CP, 28% fat MR fed at 951 g DM/d), and HPHF+ (27% CP, 28% fat MR fed at 1431 g DM/d). Animals were harvested on d 65 of life and mammary tissue was subjected to biochemical, molecular, and histological examination. By design, the effects of diet were evaluated at a common chronological age, but not necessarily at the same physiological age (body weight). Results from heifers reared on CON were compared to the average results from heifers reared on the other 3 diets. The second comparison evaluated the effect of increased fat in MR when protein content and intake were the same. The final comparison evaluated the effect of increased intake of a high-fat, high-protein MR. Neither diet composition nor nutrient intake in pre-weaned heifers affected PAR weight, PAR composition, GH/IGF-I axis gene expression, or putative mammary epithelial stem cell abundance when assessed at a common chronological age. Changes in MFP size and composition were observed, but no diet effect on GH/IGF-I axis gene expression in MFP was observed. This suggests nutrition is not critical for regulating the expression of local GH/IGF-I axis components or stem cell populations in the developing heifer mammary gland.
Ph. D.

With feed costs representing on average 65% of the total cost of production improvements in feed efficiency could have a major impact on the beef industry. Postweaning performance and feed efficiency data were collected on 114 heifers born on the University of Arizona's V bar V Ranch. Residual feed intake (RFI) was significantly correlated with dry matter intake (DMI) (r = 0.46) and G:F (r = -0.43), while G:F was moderately correlated with initial age (r = -0.54), initial body weight (r = -0.40), and average daily gain (ADG) (r = 0.68). Residual gain (RG) was moderately correlated with RFI (r = -0.41) and highly correlated with ADG (0.62) and G:F (0.73). In addition, RG was significantly correlated (r = -0.21) with initial weight suggesting that selection for RG could lead to increased cow mature size. Heifers were sorted into three breed categories: Hereford, Hereford cross, and Wagyu cross and breed effect on performance and feed efficiency traits were analyzed. Significant differences in DMI, FCR, and RG were noted, but likely due to significant differences in age at the time of testing. RFI was not significantly different between breed groups, suggesting that RFI is less influenced by animal age than other measures of feed efficiency. In addition, sires of study heifers with 5 or more progeny were selected and progeny performance and feed efficiency traits were compared between sires. No significant differences in ADG, RFI, FCR, or RG were noted between sire progeny. This was likely due to an insufficient number of progeny used in the trial. Further research and an increased number of animals used may uncover significant impacts of sire on RFI.

Current data indicates that feeding dairy calves more nutrients in early life allows them to produce more milk in the future. Mechanisms responsible are poorly understood. Thirty-six Holstein heifer calves were fed either a restricted (R; 20.2% crude protein [CP], 19.8% fat, dry matter (DM) basis, fed at 0.44 kg/hd/d, DM basis) or an enhanced (EH; 28.9% CP, 26.2% fat, DM basis, fed at 1.08 kg/hd/day, DM basis) milk replacer (MR) and given either a placebo or estradiol (E2) implant to assess differential responses to E2. Our underlying hypothesis was that calves fed more nutrients are better able to respond to mammogenic stimuli and will have a more developed mammary gland as a result of imposed treatments. Enhanced-fed calves grew at a faster rate, were heavier at weaning, and had more functional mammary tissue (i. e., parenchyma; PAR) mass in the mammary gland at weaning (7.3-fold). Additionally, biochemical composition of the PAR was not impacted by the dietary treatments imposed. Furthermore, EH-fed calves had an increase in the number of actively dividing cells throughout the mammary PAR as well as increased intensity of estrogen receptor expression in the population of cells expressing the estrogen receptor. Enhanced-fed calves had an up-regulation of genes and pathways in the PAR related to metabolism, cellular signaling, and cellular growth. When given E2, EH-fed calves experienced the greatest overall mammary gland development and had the greatest PAR mass without compromised composition. When comparing EH- and R-fed calves given E2, differential expression of genes and pathways related to cell growth, cell signaling, and metabolism was observed. In summary, data indicates that enhanced feeding of calves in early life allows increased responsiveness to mammogenic stimuli and a corresponding increase in mammary development. We suggest that this may at least partly explain the improved future milk production in calves fed in this manner.
Ph. D.

The objective was to examine the efficacy of saliva collection techniques and salivary cortisol assay to determine potential stress response in dairy heifers post challenge with adrenocorticotropin (ACTH) (Experiment 1), lactating cows without experimental stressors (Experiment 2), and gilt piglets versus boar piglets within two hours post castration stress (Experiment 3). Data were from the Holstein and Jersey dairy herd maintained by the Dairy Educational Unit at North Carolina State University and the crossbred swine herd maintained by the Swine Educational Unit also at North Carolina State University. In cattle (Experiments 1 & 2), saliva was collected using gauze squares secured by hemostats and introduced to each animalâs mouth until soaked. The same procedure was followed for the piglets (Experiment 3) with the addition of Sprite⢠to the gauze before introduction into the animalsâ mouth. Serum and saliva cortisol concentrations show a similar pattern after a stimulus to the adrenal gland with ACTH in Experiment 1. Salivary cortisol concentrations were lower than that found in serum and ranged from 27.40% to 59.94% of serum concentrations. In Experiment 2 the lack of an induced stress in lactating cows did not provide sufficient circulating cortisol for the sensitivity of the radioimmunoassay procedure utilized in this project. Data from these collections do illustrate the lack of a measureable stress response in animals from all three cow groups studied: Blood only, blood and saliva, or saliva only collection suggesting that neither sampling method elicits more stress response than the other. Sufficient saliva and circulating cortisol were obtained from the boar and gilt piglets in Experiment 3 to support our hypothesis that saliva is a viable tool for assessing stress in piglets. Mean concentrations for gilts were significantly lower than that of the castrated boars (1.36±0.301 versus 2.3074± 0.22 ng/mL).

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A reprodução é o principal fator limitante na eficiência da produção de carne, e a baixa taxa de concepção observada no rebanho brasileiro reflete a baixa taxa de fertilidade das vacas e a idade tardia à puberdade das novilhas de substituição. A fim de fornecer mais informações sobre as estratégias nutricionais para o melhor desenvolvimento das novilhas Nelore e melhorar o desempenho das vacas, foram realizados três estudos e os resultados são apresentados em quatro artigos. No primeiro trabalho, foram utilizadas 80 vacas Nelore grávidas (6 meses de gestação) com idade inicial de seis anos e peso inicial médio e escore de condição corporal inicial de 515,5 ± 1,34 kg e 4,68 ± 0,15, respectivamente. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos e vinte repetições. As estratégias avaliadas foram suplementação com 1 kg/vaca/dia de suplementação somente no pré-parto, somente no pós-parto, no pré e pós-parto, e somente mistura mineral ad libitum durante o pré e pós-parto. Observou-se o efeito da suplementação sobre o peso corporal (PC) das vacas no parto e sobre o peso dos bezerros ao nascimento (P <0,05). Houve também efeito da suplementação no pré e pós-parto (P <0,05) no PC final, ganho médio diário e escore de condição corporal final dos animais. Houve uma tendência, com a suplementação no pós-parto, de maior produção de leite das vacas (P = 0,065) e, para os seus componentes, houve efeito de suplementação no pós-parto apenas para proteína do leite (PL) (P = 0,003). Houve um efeito da suplementação no pós-parto sobre nitrogênio ureico sérico, glicose, ácidos graxos não esterificados, β-hidroxibutirato e progesterona (P <0,05). Todos os metabólitos foram influenciados (P <0,05) no dia pós-parto. As vacas suplementadas no pós-parto apresentaram maior taxa de concepção do que a observada em animais não suplementados (P = 0,005). A suplementação com 1 kg/dia de suplementação com 28,6% de PC no pré-parto melhorou algumas das características produtivas, no entanto, a suplementação no pós-parto permite efeitos mais expressivos sobre a eficiência produtiva, metabólica e reprodutiva das vacas. Portanto, a suplementação no pós-parto é recomendada quando os animais têm escore de condição corporal vi (ECC) adequada ao parto. As bezerras das vacas do primeiro experimento foram utilizadas no segundo trabalho para avaliar estratégias de suplementação no sistema creep-feeding. Utilizaram-se quarenta e quatro bezerras Nelore, com idade e peso médio inicial, de quatro meses e 147,6 ± 1,34 kg, respectivamente. Um único suplemento com aproximadamente 20% de proteína foi fornecido em quantidades diferentes dependendo do peso corporal (PC). Os tratamentos consistiram no suprimento de 0,0%, 0,2%, 0,4% ou 0,6% do PC deste suplemento. Observou-se aumento do efeito linear (P <0,05) do peso corporal final e ganho médio diário de novilhas com aumento da suplementação. A suplementação múltipla aumentou o consumo, em kg/dia, de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), matéria seca digerida (MSD) e nutrientes digestíveis totais (NDT). Não houve efeito da suplementação (P> 0,05) nas concentrações de AGNE. Houve um efeito linear crescente (P <0,05) de suplementação sobre as concentrações de insulina. Conclui-se que a suplementação melhora o desempenho, as características nutricionais e metabólicas dos animais, sendo o suprimento de 0,6% do PC de suplemento com 20% de PB o tratamento mais efetivo. As mesmas novilhas foram utilizadas no terceiro experimento após o desmame para avaliar os efeitos da suplementação estratégica de novilhas Nelore após o desmame à concepção. As estratégias avaliadas foram: BAAL - suplementação com 0,2% de PC/animal/dia de suplementação nos primeiros 90 dias e suplementação com 0,6% de PC/animal/dia nos 90 dias subseqüentes; MEME - suplementação com 0,4% de PC/animal/dia durante 180 dias; ALBA - suplementação com 0,6% de PC/animal/dia de suplementação nos primeiros 90 dias e suplementação com 0,2% de PC/animal/dia nos 90 dias seguintes; e MM - apenas mistura mineral ad libitum durante os 180 dias. Observou-se que a suplementação melhorou o desempenho dos animais durante os primeiros 90 dias de experimento, o que pode ser verificado pelo ganho médio diário (GMD) das fêmeas (P = 0,001). O mesmo fato foi observado na fase de transição seca/água, onde a suplementação melhorou o peso corporal final (PCf) (P = 0,002) e GMD (P = 0,001). Verificou-se também que a suplementação múltipla aumentou o consumo de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), matéria seca digestível (MSD) e nutrientes digestíveis totais (NDT) durante todo o experimento e fibra em detergente neutro digestível(FDNd) e fibra em detergente neutro corrigida para cinzas e proteínas (FDNcp) apenas na transição seca/água. A suplementação aumentou o coeficiente de digestibilidade aparente de MS, MO, PB, vii FDNcp e NDT (P <0,05), ou seja, de todos os parâmetros analisados. Os níveis de nitrogênio ureico sérico (NUS), glicose (GLIC), insulina (INS) e progesterona (PROG) foram maiores em novilhas suplementadas do que em novilhas não suplementadas (P < 0,05). Por outro lado, a suplementação reduziu as concentrações de ácidos graxos não-esterificados (AGNE) (P = 0,001). Finalmente, foi obsevado que a taxa de concepção foi maior em novilhas suplementadas (P = 0,002). Concluiu- se que os melhores níveis de NUS, INS, GLIC, AGNE e PROG das novilhas suplementadas associadas ao maior PCf, digestibilidade e consumo dos componentes da dieta proporcionaram melhor desempenho reprodutivo para as novilhas suplementadas, independentemente da suplementação.
Reproduction is the main limiting factor in meat production efficiency and the low offtake rate observed in the Brazilian herd reflects the low fertility rate of cows and the late age at puberty of replacement heifers. In order to provide more information about nutritional strategies to better develop Nellore heifers and to improve dams’ performance, three studies were conducted and the results are here presented in four papers. In the first paper, were used 80 pregnant Nellore cows (6 months gestation) with initial age of six years and mean initial weight and initial body condition score of 515.5 ± 1.34 kg and 4.68 ± 0.15, respectively.The experimental design was completely randomized, with four treatments and twenty repetitions. The strategies evaluated were supplementation with 1 kg/cow/day of supplementation only in the pre-partum, only in the postpartum, in the pre and postpartum, and only ad libitum mineral mixture during the pre and postpartum.The effect of supplementation on the body weight (BW) of cows at calving and calf weight at birth (P <0.05) was observed. There was also effect of pre and postpartum supplementation (P <0.05) on the final BW, mean daily gain and final body condition score of the animals. There was a trend of postpartum supplementation on milk production from the matrices (P = 0.065) and, for its components, there was post-partum supplementation effect only on milk protein (MP) (P = 0.003). There was an effect of postpartum supplementation on serum urea nitrogen, glucose, non-esterified fatty acids, β- hydroxybutyrate and progesterone (P < 0.05). All metabolites were influenced (P < 0.05) by the postpartum day. Cows supplemented postpartum had a higher conception rate than that observed in non-supplemented animals (P = 0,005). Supplementation with 1 kg/day supplementation with 28.6% of CP in pre-partum improved some of the productive characteristics, however, postpartum supplementation allows more expressive effects on the productive, metabolic and reproductive efficiency of cows. Therefore, postpartum supplementation is recommended when the animals have adequate body condition score (BCS) at calving. The heifer calves of cows used in the first experiment were used in the iii second paper to evaluate supplementary strategies in the creep feeding system. Were used fourty-four Nellore heifer calves, with age and initial mean weight, of four months and 147.6 ± 1.34 kg, respectively.A single supplement with approximately 20% of protein was provided in different amounts depending on body weight (BW). Treatments consisted in the supply of 0.0%, 0.2%, 0.4% or 0.6% of BW from this supplement.Increasing linear effect (P < 0.05) of final body weight and average daily gain of heifer calves were observed with increased supplementation. Multiple supplementation increased consumption, in kg/day, of dry matter (DM), organic matter (OM), crude protein (CP), digested dry matter (dDM) and total digestible nutrients (TDN).There was no effect of supplementation (P > 0.05) on NEFA concentrations. There was an increasing linear effect (P < 0.05) of supplementation on insulin concentrations. It is concluded that supplementation improves the performance, nutritional and metabolic characteristics of the animals, being the supply of 0.6% of BW of supplement with 20% of CP the most effective treatment.The same heifers were used in the third experiment after weaning to evaluate the effects of strategic supplementation for Nellore heifers after weaning to conception. The evaluated strategies were: BAAL- supplementation with 0.2% of BW/animal/day of supplement in the first 90 days and supplementation with 0.6% of BW/animal/day in the subsequent 90 days; MEME - supplementation with 0.4% of BW/animal/day for 180 days; ALBA - supplementation with 0.6% of BW/animal/day of supplement in the first 90 days and supplementation with 0.2% of BW/animal/day in the subsequent 90 days; and MM - only mineral mix ad libitum during the 180 days.It was observed that supplementation improved the performance of the animals during the first 90 days of experiment, and this fact can be verified by the heifers' average daily gain (ADG) (P = 0.001).The same fact was observed in the dry/water transition phase, where supplementation improved final body weight (fBW) (P = 0.002) and ADG (P = 0.001).It was also verified that multiple supplementation increased dry matter (DM), organic matter (OM), crude protein (CP), digestible dry matter (dDM) and total digestible nutrients (TDN) during the whole experiment, and digested neutral detergent fiber (dNDF), and neutral detergent fiber corrected for ash and protein (apNDF) only in the dry/water transition.Supplementation increased the total apparent digestibility coefficient of DM, OM, CP, apNDF and TDN (P <0.05), that is, of all analyzed parameters. Serum urea nitrogen (SUN), glucose (GLUC), insulin (INS) and progesterone (PROG) iv levels were higher in supplemented heifers than in non-supplemented heifers (P <0.05). On the other hand, supplementation reduced the concentrations of non- esterified fatty acids (NEFA) (P = 0.001). Finally, it was found that the conception rate was higher for supplemented heifers (P = 0.020). It was concluded that the best levels of SUN, INS, GLUC, NEFA and PROG of the supplemented heifers associated to the higher fBW, digestibility and consumption of the diet components provided better reproductive performance independently of the supplementation.

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Conselho Nacional de Desenvolvimento Científico e Tecnológic
Este trabalho foi desenvolvido a partir de três estudos. Assim, o objetivo do primeiro estudo foi identificar variáveis que afetam o consumo de concentrado (CC), e desenvolver equações para predizer o CC de bezerros leiteiros até os 64 dias de vida. O banco de dados foi composto pelos dados individuais de 189 bezerros de 8 experimentos, totalizando 6.426 observações diárias de consumo. A informação coletada dos estudos foram: peso corporal ao nascimento (PCi; kg), CC (kg/dia), consumo de leite ou sucedâneo (CL; L/dia), sexo (macho ou fêmea), raça (Holandês ou mestiço Holandês×Gir) e idade (dias). A correlação entre o CC e as variáveis quantitativas CL, PCi, PCi metabólico (PCi0,75) e idade foi estabelecida. Posteriormente, foi realizada uma avaliação gráfica do comportamento padrão dos dados; e um modelo exponencial foi escolhido. Os dados foram avaliados usando a técnica de meta-análise para estimar os efeitos fixos e os efeitos aleatórios associados aos experimentos através de modelos mistos não-lineares. A técnica de validação cruzada foi utilizada para estimar a acurácia e precisão das equações desenvolvidas, com base no quadrado médio do erro de predição (QMEP), coeficiente de correlação de concordância, que foi decomposto em acurácia (Cb) e precisão (ρ). De forma adicional, uma análise tipo “bootstrap” foi utilizada para estimar o viés associado a cada parâmetro das equações desenvolvidas. Uma correlação negativa entre CC e CL foi observada (r= -0,388), no entanto, idade apresentou uma correlação positiva com CC (r= 0.66). Não foi observado efeito do tipo de alimento líquido utilizado (leite ou sucedâneo) no desenvolvimento da equação. No entanto, foram ajustadas 2 equações, significantemente diferente para todos os parâmetros, para predizer o CC para bezerros consumindo menos que 5 (CC<5) ou mais que 5 (CC>5) litros/dia de leite ou sucedâneo: CC<5 = 0,1839±0,0581 × CL × exp((-0,0040±0,0011 × CL + 0,0333 ±0,0021 ) × (I- (6,0332 ±0,3583 × CL + 0,8302± (0,12 × CL); CC>5 = 0,1225±0,0005 × CL × exp((-0,0015±0,0001 × CL + 0,0217±0,0006) ×))) 0,5092 - (I- (1,9508 × CL + 3,5382± )))1,3140 ±0,1710 - (0,12 × CL); onde CC<5 e CC>5 = consumo predito de concentrado para bezerros que consomen menos de 5 ou mais de 5 litros/dia de leite ou sucedâneo, respectivamente (kg/dia); CL = consumo de leite ou sucedâneo (L/dia) e I = idade (dias). Estas equações apresentaram alta acurácia (Cb de 0,97 e 0,95 para CC<5 e CC>5, respectivamente) e o erro aleatório do QMEP foi de 99,8 e 99,9% para CC<5 e CC>5, respectivamente. A análise “bootstrap” indicou um baixo viés para todos os parâmetros estimados em ambas as equações. A precisão das equações foi moderada, com valores de r2 de 0,61 e 0,52 e valores de ρ de 0,78 e 0,72 para CC<5 e CC>5, respectivamente. Conclui-se que a utilização de leite ou sucedâneo como alimento líquido não afeta o CC, ou o desenvolvimento do CC ao longo do tempo, o qual aumenta exponencialmente de acordo com a idade do bezerro. O CC foi negativamente afetado pelo CL e, por esta razão, diferentes equações são necessárias para estimar o CC de acordo com o CL. O segundo estudo objetivou avaliar a influência de diferentes níveis de proteína não-degradável no rúmen (PNDR) sobre o consumo, desempenho, características de carcaça, balaço de N, desenvolvimento da glândula mamária e o status hormonal de novilhas Holandesas em diferentes estágios fisiológicos (EF). Foram utilizadas 16 novilhas pré-puberes (PRE), com peso corporal inicial de 106±7,6 kg e 4±0,46 meses de idade, bem como 16 novilhas púberes (PUB), com peso corporal inicial de 224±7,9 kg e 12±0,45 meses de idade. O experimento teve uma duração de 84 dias e foi conduzido segundo um delineamento inteiramente casualizado, segundo um esquema fatorial 4×2, com 4 níveis de PNDR na proteína total da dieta ((38, 44, 51 e 57%) e animais em duas idades diferentes (pré-puberes e púberes). Entre os dias 36 e 40 e os dias 78 e 82 os animais foram submetidos à ensaios de digestibilidade com coleta de alimentos, sobras e coletas “spot” de fezes e urina. No dia 0 (imediatamente antes do início do experimento) e dia 83 foram tomadas imagens de ultrassom na área lombar dos animais. Nos dias 0, 21, 42, 63 e 84 foram tomadas imagens de ultrassom da glândula mamaria. E, por fim, nos dias 0 e 84 foram tomadas amostras de sangue para estimar as concentrações séricas de progesterona, estrógeno, IGF-I e insulina. O EF afetou a digestibilidade aparente da MS, e novilhas PRE apresentaram menores valores. Novilhas PRE também apresentaram consumo preferencial por fibra em detergente neutro corrigida para cinzas e proteína (FDNcp) e atividade de seleção contra a proteína bruta (PB) maior que novilhas PUB. O ganho médio diário (GMD) e a retenção de N foram afetados pelo EF, e novilhas PRE apresentaram um GMD de 505 g/dia, enquanto novilhas PUB apresentaram um valor médio de 905 g/dia. Adicionalmente, estas variáveis foram afetadas pelo nível de PNDR, e maiores valores foram obtidos para o tratamento com 51% de PNDR. A análise de pixels na glândula mamária apontou efeito do EF, e novilhas PRE apresentaram maiores valores de pixel. As mensurações iniciais de progesterona sérica demonstraram que as novilhas PRE e PUB mantiveram seu EF durante o experimento. A concentração de IGF-I foi afetada somente pelo EF, e novilhas PUB apresentaram maiores valores. A concentração de insulina não foi afetada pelo EF, mas apresentou uma tendência de ser maior para os tratamentos com 51% de PNDR. Conclui-se que o nível dietético de 51% de PNDR é responsável por aumentar o desempenho de novilhas PRE e PUB. Adicionalmente, novilhas PRE tem menor habilidade de seleção, o que afeta, negativamente, a sua digestibilidade e desempenho. Finalmente, estes animais são mais propensos a ter uma maior proporção de gordura na glândula mamaria, mesmo sob moderadas taxas de crescimento. O terceiro estudo foi conduzido com o objetivo de avaliar de níveis crescentes de PNDR sobre o consumo, as digestibilidade parciais e total, a cinética e as características ruminais, bem como a utilização do N de novilhas leiteiras holandesas. Foram utilizadas 8 novilhas holandesas fistuladas no rúmen, com peso corporal inicial de 276±8,3, em delineamento em quadrado latino 4×4 duplo, com quatro níveis de PNDR na proteína dietética, como segue: 38% de PNDR (38PNDR); 44% de PNDR (44PNDR); 51% de PNDR (51PNDR) e 57% de PNDR (57PNDR). O experimento teve duração de 84 dias, subdivididos em 4 períodos experimentais de 21 dias (14 dias de adaptação + 7 dias de coletas). Foram realizadas 8 coletas “spot” de fezes, urina, conteúdo ruminal e digesta omasal, com intervalo de 8 horas entre cada coleta, como segue: no 15o dia as amostras foram coletadas as 0600h e 1500h; no 16o dia as amostras foram coletadas as 0000h, 0900h e 1800h; e no 17o dia as amostras foram coletadas as 0300h, 1200h e 2100h. No 19o dia foi realizado esvaziamento completo do rúmen 4 horas após a alimentação matutina e no 21o dia o esvaziamento foi realizado imediatamente antes da alimentação matutina. O consumo diário de MS, matéria orgânica (MO), PB, FDNcp e FDNcp potencialmente digestível (pdFDNcp) não foi afetado pelos níveis de PNDR. Adicionalmente, o consumo relativo (g/kg de peso corporal) de MS, PB e FDNcp, assim como o fluxo ruminal de MS, MO, PB, FDNcp pdFDNcp não foram afetados pelos níveis de PNDR. A digestibilidade total da MS, MO, PB, FDNcp e pdFDNcp, bem como as digestibilidade ruminal e intestinal da MS, MO, FDNcp e pdFDNcp não foram afetados pelos níveis de PNDR. No entanto, as digestibilidade ruminal e intestinal da PB apresentaram uma tendência de decréscimo de acordo com o aumento nos níveis de PNDR. Não foram observados efeitos dos níveis de PNDR sobre as taxas de ingestão, passagem e digestão, assim como sobre a concentração de ácidos graxos voláteis. O tratamento 38PNDR apresentou maior concentração de nitrogênio amoniacal ruminal em relação aos outros tratamentos. A excreção de nitrogênio urinário apresentou tendência de queda de acordo com o aumento nos níveis de PNDR. Adicionalmente, o nitrogênio retido apresentou tendência de aumento de acordo com o aumento nos níveis de PNDR e foi maior para os tratamentos 51PNDR e 57PNDR. A síntese de proteína bruta microbiana, a eficiência de síntese de proteína microbiana (PBmic) e a eficiência de uso do nitrogênio para síntese de proteína microbiana diminuíram de acordo com o aumento nos níveis de PNDR na dieta. O fluxo de PNDR aumentou, enquanto a quantidade de proteína degradável no rúmen decresceu de acordo com o aumento nos níveis de PNDR. Adicionalmente, o fluxo de proteína metabolizável apresentou tendência de aumento de acordo com o aumento nos níveis de PNDR e maiores valores foram observados para os tratamentos 51PNDR e 57PNDR. Conclui-se que a digestibilidade intestinal da PB é negativamente afetada pelos níveis de PNDR, o que é proporcionado pela redução no fluxo de PBmic, sendo que esta, provavelmente, digestibilidade intestinal da proteína maior que os alimentos. A excreção urinária de N diminui à medida que a PNDR dietética aumenta, o que é proporcionado pela queda nas perdas ruminais de nitrogênio na forma de amônia e pelo aumento na reciclagem de nitrogênio para o rúmen. A redução na excreção urinaria de nitrogênio, aliada ao aumento no fluxo de proteína metabolizável, o qual foi promovida pelo aumento no fluxo de PNDR ao intestino delgado, são determinantes para promover aumentos na retenção de nitrogênio, o que ocorreu nos tratamentos 51PNDR e 57PNDR.
This work was developed from three studies. Therefore, the objective of the first study was to identify variables that influence starter feed intake (SFI), and to develop equations to predict SFI in milk-fed dairy calves up to 64 days of age. The database was composed of individual data of 189 calves from 8 experiments, totaling 6,426 daily observations of intake. The information collected from the studies were: birth body weight (birth BW; kg), SFI (kg/day), fluid milk or milk replacer intake (MI; L/day), sex (male or female), breed (Holstein or Holstein×Gyr crossbred), and age (days). A correlation between SFI and the quantitative variables MI, birth BW, metabolic birth BW (birth BW 0.75), and age was established. Subsequently, data were graphed and based on a visual appraisal of the pattern of the data; an exponential function was chosen. The data were evaluated using a meta-analysis approach to estimate fixed and random effects of the experiments using nonlinear mixed coefficients statistical models. Cross-validation was used to estimate the accuracy and precision of the developed equations using the mean square error of prediction (MSEP), concordance correlation coefficient, which was decomposed into accuracy (Cb) and precision (ρ) parameters, and the coefficient of determination (r 2) as a proxy for precision. In addition, a bootstrap analysis was used to estimate the bias associated with each parameter of the developed equation structure. A negative correlation between SFI and MI was observed (r = –0.388), but age had a positive correlation with SFI (r =0.66). No effect of liquid feed source (milk or milk replacer) was observed in developing the equation. However, 2 equations, significantly different for all parameters, were fit to predict SFI for calves that consume less than 5 (SFI<5) or more than 5 (SFI>5) L/day of milk or milk replacer: SFI<5 = 0.1839±0.0581 ×MI×exp((-0.0040±0.0011× MI + 0.0333 ±0.0021) × (A- (6.0332 × MI + 0.8302±)))±0.35830.5092 - (0.12 × MI); CC>5 = 0.1225±0.0005 × MI × exp((-0.0015±0.0001 × MI + 0.0217±0.0006) × (A- (1.9508±0.1710 × MI + 3.5382±1.3140))) - (0.12 × MI); whereSFI<5 and SFI>5 = starter feed intake prediction for calves that consume less than 5 and more than 5 L/day of milk or milk replacer, respectively (kg/d); MI = milk or milk replacer intake (L/d) and A = age (days). These equations had high accuracy (Cb of 0.97 and 0.95, respectively) and the random errors of MSEP were 99.8 and 99.9% for SFI<5 and SFI>5 equations, respectively. Small biases were observed with the bootstrap analyses for all estimated parameters. The equations’ precision was moderate, with r 2 values of 0.61 and 0.52 and ρ values of 0.78 and 0.72 for SFI<5 and SFI>5, respectively. In conclusion, the use of milk or milk replacer as liquid feed did not affect SFI, or development of SFI over time, which increased exponentially with calf age. Starter feed intake was negatively affected by MI and, and for this reason, different equations are necessary to predict calf SFI according to MI. The second study aimed to evaluate the influence of different levels of rumen undegradable protein (RUP) on intake, performance, carcass characteristics, N balance, mammary gland development and hormonal status of Holstein heifers at different physiological stage (PS). Sixteen prepubertal (PRE) heifers with 106±7.6 kg of initial body weight and aged 4±0.46 months old, as well as, 16 pubertal (PUB) heifers with 224±7.9 kg of initial body weight and aged 12±0.45 months old were used. The experiment was carried out during 84 days following a complete randomized design, in a 4×2 factorial arrangement, with four levels of RUP in dietary protein (38, 44, 51, and 57%), and animals at two PS (prepubertal or pubertal). Between days 36 and 40 and between days 78 and 82 the animals were subjected to digestibility trials with collections of feeds, orts and spot collections of feces and urine. At days 0 (immediately before the beginning of the experiment) and 83 body ultrasound images were taken at the rib area. At days 0, 21, 42, 63 and 84 images of the mammary gland were taken via ultrasound. Finally, at days 0 and 84 blood samples were taken to estimate serum concentration of progesterone, estrogen, IGF-I and insulin. The PS affected the apparent digestibility of DM, and PRE heifers presented lower values. The PRE heifers also presented a preferential consumption for neutral detergent fiber corrected for ash and protein (NDFap) and sorting activity against CP greater than PUB heifers. The average daily gain (ADG) and N retention were affected by PS, and PRE heifers presented an ADG of 505 g/d, while PUB heifers presented an average value of 905 g/d. In addition, these variables were affected by RUP levels, where greater values were obtained for treatments with 51% of RUP. The analysis of pixels in mammary gland images pointed effects of PS, and PRE heifers presented greater pixels values. The initial and final measurements of serum progesterone demonstrated that PRE and PUB heifers kept their PS during the experiment. The IGF-I concentration was only affected by PS, and PUB heifers presented greater values. In addition, insulin was not affected by PS, but presented a tendency to be greater at treatments with 51% of RUP. In conclusion, the dietary level of 51% of RUP is responsible to increase the performance of PRE and PUB Holstein heifers. In addition, PRE heifers have lower sorting ability, what affected, negatively, their digestibility and performance. Finally, these animals are more likely to have greater fat proportion in the mammary gland, even under moderate rates of growth. The third study aimed to evaluate the influence of increasing levels of RUP on intake, total and partial digestibilities, rumen kinetics and characteristics, as well the N use of dairy Holstein heifers. Eight rumen-cannulated Holstein heifers, with an average initial body weight of 276±8.3 were used in a double 4×4 Latin Square design with four levels of RUP in the total dietary protein, as follows: 38% of RUP (38RUP); 44% of RUP (44RUP); 51% of RUP (51RUP) and 57% of RUP (57RUP). The experiment was carried out during 84 days subdivided into 4 experimental periods of 21 d (14 d for adaptation + 7 d for collections). Eight spot collections of feces, urine, ruminal content and omasal digesta were performed with 9 hours interval between each collection, as follows: on 15th d samples were collected at 0600 h and 1500 h; on 16th day samples were collected at 0000 h, 0900 h and 1800 h; on 17th d samples were collected at 0300 h, 1200 h and 2100 h. On 19th d a complete rumen evacuation was performed, 4 hours after the morning feeding and on 21st d immediately before morning feeding. Daily intake of DM, organic matter (OM), CP, NDFap and potential digestible NDFap (pdNDFap) were not affected by RUP levels. In addition, the relative intake (g/kg of body weight) of DM, CP and NDFap, as well as the ruminal outflow of DM, OM, CP, NDFap and pdNDFap were not affected by RUP levels. Total digestibility of DM, OM, CP, NDFap and pdNDFap, as well as ruminal and intestinal digestibilities of DM, OM, NDFap and pdNDFap were not affected by RUP levels. However, ruminal and intestinal digestibilities of CP presented a tendency to decrease according to RUP supply increase. Effects of RUP levels were not observed on the ingestion, passage and digestion rates, as well on the total volatile fatty acid concentration. Treatment 38RUP presented greater concentration of rumen ammonia nitrogen in relation to the other treatments. The urinary N excretion presented a tendency to decrease according to RUP supply increase. In addition, retained N presented a tendency to increase according to RUP levels and greater values were observed for treatments 51RUP and 57RUP. Microbial crude protein (CPmic) synthesis, microbial efficiency and the efficiency of use of N for microbial synthesis, decrease as the supplied RUP increases. Flow of RUP increased, while the amounts of rumen degradable protein decrease according to RUP supply increase. In addition, the flow of metabolizable protein presented a tendency to increase and greater values were observed for treatments 51RUP and 57RUP. In conclusion, the intestinal digestibility of CP is negatively affected by RUPvlevels, what is due to the reduction in the CPmic flow, which, probably, has greater intestinal digestibility than protein of feedstuffs. The urinary N excretion decrease according to RUP supply increase, what is due to the decrease in ruminal N losses as ammonia and the increase in N recycling. The reduction in the urinary N excretion allied to increases in the flow of metabolizable protein, which are promoted by increases in the flow of RUP to the small intestine, are determinant to promote increases in the retained N, which occurred for treatments 51RUP and 57RUP.

Genetic improvement in cattle has focused in recent years on the large reproductive potential that resides in the ovaries of females at an early age. It is estimated that approximately 150,000 oocytes are present in primordial follicles in foetal ovaries at birth, and recruitment of follicles from the primordial pool has been initiated by the time of birth. Further, follicular growth can be superstimulated in heifer calves from around 4 weeks of age by treatment with gonadotrophins, and oocytes recovered and placed through in vitro maturation and fertilisation procedures to produce viable embryos.

The capacity to use embryos derived from heifer calves has the potential to reduce generation intervals and increase the rates of genetic gain in cattle. Studies on embryo production from heifer calves have reported inconsistent and unpredictable responses to superstimulation of follicle growth with FSH, similar to that observed in sexually mature heifers. Heifer calves that had a relatively large (>10mm) follicle on the ovary at the end of superstimulation, had a smaller number of total follicles compared with heifer calves that did not have a large follicle on the surface of the ovary. This observation led to the suggestion that follicular interrelationships may occur from an early age in heifers, and that a large follicle may suppress the development of other follicles. Nutrition appears to influence ovarian follicle status in peri-pubertal and pubertal heifers and possibly the response to superstimulation of follicular growth in older animals. There may be a role, therefore, for nutrition in ovarian follicle growth and responses to superstimulation in heifer calves.

In a number of studies oocytes obtained from heifer calves were reported to have a reduced developmental competency in vitro compared with oocytes obtained from ovaries of post-pubertal heifers.

In cattle, treatment with agonists of gonadotrophin hormone releasing hormone (GnRH) desensitises the anterior pituitary gland to GnRH which blocks pulsatile secretion of LH but allows continued basal LH secretion. Antagonists of GnRH prevent both pulsatile and basal secretion of LH. It is possible that treatment with GnRH agonists and antagonists might be used to regulate gonadotrophin secretion in heifer calves and prevent the development of large (functionally dominant) follicles. Subsequent initiation of superstimulation when a pool of small gonadotrophinresponsive follicles are present on the ovaries, and maturing these follicles in synchrony in vivo, may allow a pool of oocytes at similar stages of maturation to be collected for in vitro procedures.

The first two experiments in this thesis examined the requirement of LH for oocyte maturation by treating calves with gonadotrophin hormone releasing hormone (GnRH) agonist and antagonist before and during superstimulation with FSH. Simultaneous treatment with a GnRH agonist during superstimulation of ovarian follicle growth with FSH tended to increase the number of follicles stimulated to grow and significantly increased the number of Grade A and Grade B oocytes collected. In a second experiment, treatment with a GnRH antagonist tended to increase blastocyst development rate after in vitro fertilisation. It was concluded from these findings that exposure of oocytes to pulsatile secretion of LH, and/or a 'pre-ovulatory like' surge release of LH, is not an obligatory requirement for oocyte growth and development in heifer calves.

A third experiment examined the effects of nutrition and growth rate on maturation of the reproductive endocrine axis and the response of calves to superstimulation of ovarian follicle growth with FSH. Heifer calves were raised on two planes of nutrition (relatively low and high) and subsequently superstimulated with FSH. The nutritional treatments resulted in a significant difference in growth rate between the two groups of heifers. However, there were no apparent differences in ovarian follicular responses to stimulation with FSH, oocytes recovered, or in vitro developmental competency of oocytes, between the two groups of heifers.

In the fourth experiment, in vitro developmental competency was compared between oocytes obtained from heifer calves superstimulated with FSH, heifer calves that had not undergone superstimulation and post-pubertal heifers and cows that had not been stimulated with FSH. There were no differences in developmental competency between Grade A and Grade B oocytes derived from the three groups of animals. This finding demonstrated that oocytes obtained from pre -pubertal heifers do not have an intrinsic reduced capacity for in vitro development compared with oocytes obtained from post -pubertal heifers.

The ultimate test of viability of embryos derived from heifer calves is the transfer to recipients and the birth of calves. The aim of the fifth experiment therefore was to test the viability of embryos derived from 10 week-old heifer calves in which ovarian follicular growth was superstimulated with FSH. Transfer of blastocysts produced from oocytes obtained from heifer calves to recipient sexually mature heifers resulted in the birth of normal calves.

In summary, the competency of oocytes collected from heifer calves from an early age has been well established in the series of experiments undertaken in this thesis. The use of superstimulation protocols with heifer calves pre-treated with a GnRH agonist or antagonists increased the number of Grade A and Grade B oocytes, and tended to increase the development to blastocyst post-fertilisation. Grade A and Grade B oocytes collected from heifer calves form blastocysts at rates comparable to oocytes collected from mature cows, and establish pregnancies which result in the birth of calves.

The aim of this study was to evaluate the effects of M. elsdenii (Me) dosing on dairy heifer performance. A secondary set of data (feed intake, heifers birth weights, age and Weight at insemination, and first lactation milk performance) of heifers (dosed and not dosed with Me) was obtained from the dairy herd of the Agricultural Research Council – Animal Production. Data were arranged in a complete randomised design and analysed as repeated measures. Milk, pre-weaning starter and metabolised energy intake did not differ between the control and the Me groups. Post-weaning starter feed intake was higher (p=0.03) for Me fed heifers than control heifers. The post-weaning metabolisable energy intake was also higher (p=0.03) for heifer fed Me than control heifers. The average daily weight gain of heifers dosed with Me was higher during the pre-weaning period (0.66 kg/day; p=0.04) and after weaning (1.12 kg/day; p=0.03) compared to control (0.60 and 0.65 kg/day, respectively). At 42 and 70 days old, the BW of Me-heifers was greater (75.8 ± 2.6 and 91.2 ± 4.6 kg) than control heifers (61.9 ± 2.6 and 77.2 ± 4.6 kg) (p<0.05). There was no difference (P>0.05) in BW at insemination, number of insemination and milk yield between the two groups of cows (p>0.05). Early feeding of Me to heifers in the present study positively affect heifer growth during and early after milk feeding period, confirming previous report. Animal weight at puberty and the subsequent milk production were not influenced by feeding Me. It is possible that Me did not survive long after weaning to continue to express its influence on animal performance.
Agriculture and  Animal Health
M. Sc. (Agriculture)

Management factors affecting dairy calves have broad impacts on behavioral development and implications for long-term welfare, and research in this area is increasingly focused on understanding the behavioral needs of the calf, to refine management and improve understanding of welfare. In this chapter, we summarize recent research addressing behavioral needs of pre-weaned calves and post-weaned heifers, encompassing aspects of social interactions and feeding, rest and comfort, and opportunities for other behavioral expression. In general, evidence suggests welfare and performance benefits of accommodating more natural behavioral expression, including social contact, higher milk intakes fed via a teat, dietary variety, and space and resources to accommodate preferred activities, such as grooming and play. Throughout these sections, consequences of restricting these behaviors includes development of abnormal oral behaviors. Emerging themes of this area of research include consideration of individual differences and implications and approaches to accommodate broader behavioral expression through increasing environmental complexity.

The article examines the reflection of Heinrich Heine’s poetry and persona in the work of the contemporary Russian poet Timur Kibirov who was greatly influenced by Heine though not through original texts but through numerous translations into Russian (so called “Russian Heine”). This influence is acknowledged by Kibirov in his poem in prose Dead Crones and demonstrated in this article on several levels: the level of direct references to Heine; the level of individual quotes and allusions; the level of fundamental principles of poetics and worldview. The creative reception of Heine by Kibirov is highly unusual and goes far beyond the traditional attitude toward the German poet: Heine is commonly perceived as a rebel, a sufferer and the last Romantic poet whose writings highlight ironic dissonances, while in Kibirov’s creations he appears as a harmonic personality, and his poetry — as a kind of vaccine against decadent worldview and “Romanticism”.

Chapter 7 chronicles Justice Washington’s domestic life as the owner of Mount Vernon after he moved to the estate in 1802. The first part details his collaboration with Chief Justice Marshall on an official biography of George Washington, based on Bushrod’s inheritance of his uncle’s papers. The second part talks about the justice’s management of the estate and its slow decline, due in part to the cost of running America’s greatest tourist attraction. The final part looks at daily life for the Washington family, the enslaved people who lived on the estate, and the free Blacks who called Mount Vernon home.

This chapter explores the basic concepts that arise when real numbers and continuous functions are studied, particularly the limit concept and its use in proving properties of continuous functions. It gives proofs of the Bolzano–Weierstrass and Heine–Borel theorems, and the intermediate and extreme value theorems for continuous functions. Also, the chapter uses the Heine–Borel theorem to prove uniform continuity of continuous functions on closed intervals, and its consequence that any continuous function is Riemann integrable on closed intervals. In several of these proofs there is a construction by “infinite bisection,” which can be recast as an argument about binary trees. Here, the chapter uses the role of trees to construct an object—the so-called Cantor set.

On a warm October afternoon in Leipzig, a hunched-over figure sits in the shadow of the monumental plastic sculpture “Aufbruch” (“Beginning”), a legacy of socialist realism that depicts a group of people struggling to move forward, as if awakening to political consciousness. Heike is tense; she gazes fixedly down at the ground, her hands clasped tightly in front of her. She is brooding on her quarter-century in the SED as a student and then professor here at Karl-Marx Universität—now, in 1991, again called Leipzig University. “Nie wieder,” repeats Heike. “Never again.” Never would she join the reconstituted SED, now called the PDS. Never again would she join any party or movement, of whatever political stripe. She is not quoting the campaign slogan used by the CDU in March 1990—already a bygone era—but is simply expressing a personal statement. Politics holds no interest for her. Her experience in the SED has disillusioned her toward—or, as she says, “inoculated” her against—party and ideological appeals. Permanently. “I have learned my lesson,” Heike says. Looking up, she follows my gaze to the grotesque socialist realist sculpture, remarking that, since the Wende in 1989, she has been looking at it with a new eye. Across the courtyard stands a much older sculpture: a towering statue of Leibniz. Heike turns to it, deliberately, as if appealing to the wise old Leipzig professor—indeed to the classical spirit of the Enlightenment itself—for guidance and support. I’m still thinking about the marches that brought down the SED regime and East Germany itself, only two Octobers ago. Just a few yards beyond Leibniz is the sacred spot where the already historic marches arose and the “We are The People” chants against the Honecker regime began. Heike, 46, a wissenschaftliche Assistentin (lecturer) in Slavic literature at the University, speaks in soft German—entirely free of Americanisms, unlike the speech of most West Germans—about her decades in the Party. Pale yet animated, her face is vital with expression, if lined with years; like many eastern German women, she wears no makeup.

This chapter focuses on challenges to the heir apparent, when, despite an established pattern of succession, a lawmaker wishing to ascend the so-called leadership ladder to a newly vacant position is challenged by another candidate. These types of races often occur when the heir apparent is politically vulnerable or a sizeable group of partisans support a rival on political or personal grounds. The chapter analyzes three challenges to the heir apparent. The first was probably the most famous example of this type of race in the contemporary House—the 1976 race for Democratic majority leader—and the other two were races for Republican majority leader in early 2006 and, after that year's congressional elections, Democratic majority leader. In all three instances, one of the candidates running for majority leader was serving as whip, a position that at the time was the “natural” precursor to becoming leader.

The article shows the effect of the use of phytoadditives based on sandy sainfoin in the diet on the digestibility coefficient, on the dynamics of live weight and the natural resistance of the body of calves during the milk growing period. The studies were carried out in the conditions of the Perm Territory. In the course of the studies carried out on three experimental groups of heifers, 10 heads each, it was found that feeding phytosupplements in the amount of 0.150 kg and 0.300 kg per head per day had a positive effect on the digestibility coefficients, live weight and natural resistance of experimental animals.

The aim of this study was to examine the values of energy and protein status indicators of Holstein Frisian dairy cows in different production periods (20 days before calving, 30th and 90th day of lactation period). The study included 76 clinical healthy cows, which were divided into 2 groups. The first group consisted (n = 38) of pregnant heifers (or cows in first lactation after calving), and the second group (n = 38) consisted of cows calved multiple times (cows from second to fourth lactation). The results indicate that average concentration of glucose, albumins and urea at both groups in all phases of investigation are not significantly different in tested specimens (p>0.05). β-hydroxybutyrate concentration (BHBA) at pregnant individuals in late pregnancy period was statistically lower than 30th and 90th day of lactation, with p<0.05 at first and p<0.01 at second group. Lower values of total proteins at both groups were recorded 20 days before calving relative to lactation period, with statistical signifikante at p<0.01 for the first and p<0.05 for the second group. Heifers’ blood globulin concentration was significantly lower (p<0.05) relative to values determined after calving, during lactation period. Multiparous cows before calving also had lower average values of globulin, but differences were not significant.

Applied computer solutions for conductive heat transfer are a critical component in any modern undergraduate heat transfer course. This need has been addressed in many ways through various textbook exercises and software packages. The present work involves a catalog of analytical solutions organized with a numbering system that describes the boundary conditions and initial conditions for each problem. The solutions are pre-programmed and accessible via a free web site called the Exact Analytical Conduction Toolbox, or EXACT. Students can access these solutions for use in homework and project work. In this paper examples of several types of student exercises are given, including a re-creation of the Heisler charts and a two dimensional steady-state example. Additionally, an account is given of classroom use of these tools in a graduate heat transfer course, outlining the education advantages of the EXACT web page. The concept of intrinsic verification is also discussed, focusing on the applicability of this concept to enhancing insight among undergraduate students. General support is also expressed for the need of analytical solutions to heat transfer and diffusion problems in an undergraduate setting.

The felt load of life is often mirrored to well-being and how people feel. Typically organizations are looking the workload of their staff because that is the thing which organizations can affect and made adjustments. Organization´s culture often starts to change people to be alike and large tendencies and trends are carving people to feel and act as same. In this research we are looking how university students and personnel feel about heir workload and how they feel their team spirit and mood. This research will be conducted by utilizing two different questionnaire tools called Eezy Spirit and Student barometer. Eezy spirit is a questionnaire, which has been developed to study employee experience and it is widely used in Finland in different industries. It was chosen to be the one for studying the staff experience since it has questions about felt justice and personnel´s feelings towards management. Student barometer is a questionnaire for higher education students in Finland. It´s objectives are to provide data and information for researchers, research institutes education developers and decision makers in the institutes. Student barometer handles a variety of different matters from student life by asking students´ opinions from quality of studies to their civil life activities and their expectations of the future. This research will be based on material from Turku University of Applied Sciences (TUAS). Data will be gathered from Eezy spirit employee experience questionnaires done annually 2016-2020. The study was done to whole personnel in TUAS and number of respondents varied from 598 to 633 in different years. Respondents answered to propositions in Likert scale 1-4 and “I don´t know”. Number of propositions varied between years from 63 to 65. Respondents were grouped to units which were responsible for specific degree programs. Student barometer data consists of 2165 individual students as respondents in year 2019. They answered at most to 201 different questions and propositions. As the questionnaire was dynamic and depended partly on the previous answers, not all the questions and propositions were targeted to all of the students. Also the students’ responses were grouped by their degree programs, which makes it possible to compare the felt justice of the staff members to that of the students per each degree program. We utilize data sets between years 2016-2020. Data is analyzed with Excel and SPSS. Samples were taken from the data mass and were composed to a statistical model with excel spreadsheet. Staff members as well as students were grouped under schools and arithmetic averages and standard deviations were calculated to each proposition. After calculating the arithmetic averages further analysis was done with SPSS statistical analysis program. In SPSS proposition’s correlations were analyzed by single tailed Pearson correlation.The overall research question is: Is there a correlation between 1) workload for university students and staff 2) team spirit and relationships in organization? If so, how can this correlation be interpreted and what conclusions can be made? Future research aspects and practical recommendations will also be issued in the paper.

Feed inputs represent the largest variable cost of producing meat and milk from ruminant animals. Thus, strategies that improve the efficiency of feed utilization are needed to improve the global competitiveness of Israeli and U.S. cattle industries, and mitigate their environmental impact through reductions in nutrient excretions and greenhouse gas emissions. Implementation of innovative technologies that will enhance genetic merit for feed efficiency is arguably one of the most cost-effective strategies to meet future demands for animal-protein foods in an environmentally sustainable manner. While considerable genetic variation in feed efficiency exist within cattle populations, the expense of measuring individual-animal feed intake has precluded implementation of selection programs that target this trait. Residual feed intake (RFI) is a trait that quantifies between-animal variation in feed intake beyond that expected to meet energy requirements for maintenance and production, with efficient animals being those that eat less than expected for a given size and level of production. There remains a critical need to understand the biological drivers for genetic variation in RFI to facilitate development of effective selection programs in the future. Therefore, the aim of this project was to determine the biological basis for phenotypic variation in RFI of growing and lactating cattle, and discover metabolic biomarkers of RFI for early and more cost-effective selection of cattle for feed efficiency. Objectives were to: (1) Characterize the phenotypic relationships between RFI and production traits (growth or lactation), (2) Quantify inter-animal variation in residual HP, (3) Determine if divergent RFIphenotypes differ in HP, residual HP, recovered energy and digestibility, and (4) Determine if divergent RFI phenotypes differ in physical activity, feeding behavior traits, serum hormones and metabolites and hepatic mitochondrial traits. The major research findings from this project to date include: In lactating dairy cattle, substantial phenotypic variation in RFI was demonstrated as cows classified as having low RMEI consumed 17% less MEI than high-RMEI cows despite having similar body size and lactation productivity. Further, between-animal variation in RMEI was found to moderately associated with differences in RHP demonstrating that maintenance energy requirements contribute to observed differences in RFI. Quantifying energetic efficiency of dairy cows using RHP revealed that substantial changes occur as week of lactation advances—thus it will be critical to measure RMEI at a standardized stage of lactation. Finally, to determine RMEI in lactating dairy cows, individual DMI and production data should be collected for a minimum of 6 wk. We demonstrated that a favorably association exists between RFI in growing heifers and efficiency of forage utilization in pregnant cows. Therefore, results indicate that female progeny from parents selected for low RFI during postweaning development will also be efficient as mature females, which has positive implications for both dairy and beef cattle industries. Results from the beef cattle studies further extend our knowledge regarding the biological drivers of phenotypic variation in RFI of growing animals, and demonstrate that significant differences in feeding behavioral patterns, digestibility and heart rate exist between animals with divergent RFI. Feeding behavior traits may be an effective biomarker trait for RFI in beef and dairy cattle. There are differences in mitochondrial acceptor control and respiratory control ratios between calves with divergent RFI suggesting that variation in mitochondrial metabolism may be visible at the genome level. Multiple genes associated with mitochondrial energy processes are altered by RFI phenotype and some of these genes are associated with mitochondrial energy expenditure and major cellular pathways involved in regulation of immune responses and energy metabolism.