Replacement heifer rearing is critical for the future of the dairy operation, especially to improve genetic merit and maintain herd size. A replacement heifer from the day she is born to the day she calves herself is generally a 2-year investment without potential income. A myriad of options exists on how to manage, fed, and ultimately raise replacement heifers. This study quantifies the costs associated with replacement heifer management decisions from birth to calving related to housing, labor, feed and health. The heifer rearing period can be broken into pre and post weaning sections to allow for more understanding the variation of these different biological time periods. Variation can influence the investment per day and breakdown of resources required from a dairy producer. Total heifer raising cost varied broadly across all management scenarios in our study, with feed and labor consistently representing over 60% of the total cost. After determining the true cost on an individual farm, or providing developed assumed cost for a change in management, producers can better manage current expenses and be more prepared for future investment.

Orientador: Simone Biagio Chiacchio / Resumo: A pecuária no Brasil evolui a cada ano buscando avanços genéticos como, animais mais rústicos e precoces. A raça Nelore é à base do rebanho comercial de corte brasileiro, correspondendo a cerca de 80% do rebanho nacional, e ainda com poucos estudos sobre o período pré o pós-natal de bezerros desta raça que é extremamente adaptada às condições climáticas, resistência a ecto e endo parasitas, além de boa fertilidade mesmo em condições de escassez de alimento de alta qualidade. Buscando técnicas que proporcionam menor estresse no monitoramento gestacional, o acompanhamento via avaliação da frequência cardíaca materna fetal e a variabilidade da frequência cardíaca estão em desenvolvimento. A importância de procedimentos adequados durante as fases que antecedem o parto, período pré-natal e o período neonatal diminuem a mortalidade dos neonatos, melhorando a assistência veterinária neste momento crítico. Assim este estudo teve como objetivo avaliar parâmetros clínicos, índices eletrocardiográficos (ECG) e de variabilidade cardíaca (VFC) em vacas (n=10) (período pré e pós parto) e nos fetos (n=10), 35 dias pré parto, e na fase neonatal até 35 dias de idade. Os momentos de análise foram 35°, 28°, 21°, 14°, 7 ° 1° dia antes do parto e ao 1°, 7°, 14°, 21°, 28° e 35° dias pós-parto. Os neonatos apresentaram boa adaptação com o avançar da idade, foram verificadas poucas alterações no ECG desta categoria, com isso verificou-se que bezerros saudáveis se adaptam bem as alterações da fase fe... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Livestock in Brazil evolves every year looking for genetic advances such as more rustic and precocious animals. The Nellore breed is based on the commercial Brazilian beef bank, corresponding to about 80% of the national bank, and still with few studies on the pre or post-natal period of calves of this breed which is extremely adapted as climatic conditions, ecto resistance. and endo parasites in addition to good fertility even in conditions of scarcity of high quality food. Seeking techniques that provide less stress on pregnancy monitoring, or monitoring via maternal heart rate and heart rate variability are under development. The importance of the procedures used during the phases that precede birth, the prenatal period and the neonatal period decrease the mortality of neonates, improving veterinary assistance at this critical moment. Thus, this study aimed to evaluate clinical criteria, electrocardiographic indexes (ECG) and cardiac variability (HRV) in cows (n = 10) (pre and postpartum period) and in cases (n = 10), 35 days before delivery. pregnancy, and in the neonatal phase until they reach 35 days of life The moments of analysis were 35 °, 28 °, 21 °, 14 °, 7 ° 1 ° day before participating and on the 1 °, 7 °, 14 °, 21, 28 and 35 days postpartum. The newborns showed good adaptation with advancing age, less changes in the ECG were verified in this category, with this it was verified whether calves adapt as well as changes in the fetal to neonatal phase, resulting in a... (Complete abstract click electronic access below) / Mestre

The objective of this study was to examine specific factors that affect the selling price of feeder calves marketed through the Mississippi Feeder Calf Board Sale program, an alternative marketing strategy developed to offer producers an opportunity to increase prices received for their calves. A hedonic model was utilized to measure the effects of individual lot attributes on price. Results of sales conducted from 2008 to 2016 revealed a positive relationship between sale price and steer percentage, Brahman influence, the provision of information on growth implant practices, and number of loads per lot. Conversely, price was negatively associated with number of days from sale to loadout and the consignment of assembled lots or those consigned from multiple sellers. Lot hide color classification demonstrated varying effects on prices received. This data can enable commercial producers to evaluate production practices and make educated management decisions to improve the value of their cattle.

Beef cattle production in the southeastern United States differs in size, practice, and production type from other U.S. regions. Smaller, cow-calf type operations dominate in this region because the climate, forage availability, and other land use practices of farmers make this type of cattle operation more ideal for the Southeast. This research summarizes the current practices and characteristics that define the Southeastern cow-calf operation of today’s market and operating environment; it also examines the factors that influence the variability of beef production in these operations. Results indicate the following major points: 1.) 53.0% of respondents with commercial cows have fewer than 50 head. 2.) Weaning weight and its variability tend to increase as calves get older. 3.) Calves on seedstock operations wean heavier than those typical of cow-calf operations. 4.) Operators that are more financially invested in their operation seem to be more attentive to outcomes of their production process.

<p>Dairy calves in the preweaning period are exposed to a variety of stressors (e.g. disbudding, castration, etc.) and management practices that have the potential to influence their health and productivity later in life. Proper colostrum management at birth is the first step in ensuring calves can reach their full potential in terms of health, growth, and development, while improper management increases a calf’s risk of failed transfer of passive immunity <strong>(FTPI)</strong> which puts the calf at an increased risk of morbidity and mortality. Previous research has indicated there is a difference in colostrum management practices between dairy bull and heifer calves. Due to the marketing of dairy-beef crossbred calves as surplus animals along with dairy bull calves, there is growing interest in the treatment of these calves on farms. The first study presented here (Chapter 2) investigated the relationship between colostrum management practices on 15 farms and the prevalence of FTPI between purebred dairy and dairy-beef crossbred calves on those farms. The results of this study found no influence of calf breed (purebred dairy or dairy-beef crossbred) on the prevalence of FTPI. However, farm tended to influence FTPI. There was also a significant influence of the reported timing of the first colostrum feeding on FTPI, with calves on farms reporting feeding colostrum within 1 hour of birth having decreased odds of experiencing FTPI. In addition to colostrum management at birth, calves are exposed to several management factors during the preweaning period that can cause stressful experiences and result in negative behavioral and physiological outcomes. Early life stress, especially chronic stress, can negatively impact calves later in life. Short term stress load in calves can be quantified by measuring cortisol in the blood serum or saliva; however, these measures are not reflective of chronic stress load because they only measure circulating cortisol. The second study (Chapter 3) considered the efficacy of utilizing hair cortisol concentration <strong>(HCC)</strong> as a measure of stress load in 27 dairy calves exposed to a weekly saline injection or a weekly or biweekly repeated acute stressor (Cosyntropin injection) during the preweaning period. The results revealed no difference in HCC between the treatment groups, though salivary cortisol was increased in calves injected with Cosyntropin. Additionally, calf behavior and growth were not influenced by the treatments in this study. Overall, these studies provided insights into two areas that have not been extensively researched. First, considering dairy-beef crossbred calf management, and second investigating a method to assess chronic stress that has not been extensively researched in calves.</p>

The variability in calf management can change the physiological state of the calf as they are weaned or attain puberty. It is up to the producer to ensure that the calves develop properly to meet their expected needs on the farm. While there are guidelines from the NRC in place, there is a substantial range in the amount of protein and fat that a calf can be fed. This physiological state can be reflected in the proteins produced in tissues, the expression of gene regulatory pathways, or even the microbes present in the gut. The purpose of this study was to examine how an increase in dietary energy in milk replacer of pre-weaned Holstein heifers impacts the microbial profile of the rumen as well as the transcriptome in tissues related to growth and metabolism. Our hypothesis was that pre-weaned Holstein heifers on milk replacer diets with lower dietary energy will have a different rumen microbiome composition and a different transcriptome in growth related tissues. Holstein heifer calves (n = 36) were assigned randomly to 1 of 2 milk replacer diets: restricted (R; 20.9% CP, 19.8% Fat; n = 18) or enhanced (E; 28.9% CP, 26.2% Fat; n = 18). Calves were euthanized and rumen fluid was collected at pre-weaning (8 wks; n = 6) or post-weaning (10 wks; n = 6). Liver (L), adipose (A), and longissimus dorsi (LD) tissues were collected at pre-weaning (8 wks; n = 12). Average daily gain (ADG) and gain-to-feed ratio (G:F) were calculated for each calf. Analysis of ADG and G:F was performed using a PROC GLM in SAS with diet as the main effect; E calves had increased ADG and G:F compared to R calves. For rumen samples, libraries were constructed from extracted DNA and DNASeq was conducted using a paired-end analysis at 100 bp using Illumina HiSeq 2500. Operational taxonomic unit (OTU) clustering analysis was conducted using the 16s rRNA Greengenes reference. A PERMANOVA analysis was conducted in R to determine OTU populations for age and treatment. There was no difference in microbiome composition between pre-weaning and post-weaning calves (P = 0.761). Microbiome composition differed between E and R calves (P < 0.001). Bacteroidetes and Firmicutes represented the most abundant phyla for both E and R calves. Enhanced calves had 49.4% (5141 reads) Bacteriodetes and 36.4% (3789 reads) Firmicutes; whereas, R calves had 31.6% (2491 reads) Bacteriodetes and 41.1% (3236 reads) Firmicutes. For L, A, and LD samples, libraries were constructed from extracted RNA for RNA-Seq analyses. RNA-Seq analysis was performed using CLC Genomics Workbench and the Robinson and Smith Exact Test was used to identify differentially expressed genes between diets. There were 238 differentially expressed genes in A, 227 in LD, and 40 in L. Of the differentially expressed genes, 10 appeared in at least 2 tissues. PANTHER was used to identify functional categories of differentially expressed genes. The majority of genes were associated with metabolic processes (A = 112, 26.7%; L = 16, 32.0%; LD = 81, 34.0%) or cellular processes (A = 93, 22.1%; L = 13, 26.0%; LD = 73, 30.7%). In E calves, upregulated genes included those regulating NADH dehydrogenation (LD = 17, A = 5; i.e. ND1, ND4), gluconeogenesis (LD = 2, A = 6; i.e. ALDOB, PCK2), and cell proliferation (LD = 2, A = 3; i.e. GADD45A, CDKN1A). There was a difference in both the transcriptome and rumen microbiome of calves fed differing levels of dietary energy. The calves on the R diet had a rumen microbial composition more similar to a younger calf, while the composition of E calves was more similar to a mature calf. The change in regulation of genes involved in the cell cycle and ATP synthesis in response to dietary energy could explain the change in ADG between diets. Because the R calves appeared to have stunted development of their microbiomes and an expression profile similar to oxidative stress, it is possible that the R diet did not meet the nutritional requirements of that calves. / Master of Science

Pasture-based beef production is well-suited for the Appalachian region of the United States. This research investigated pasture, beef cattle, and economics components within the cow-calf sector of pasture beef production, and presents implications of their interplay for the vitality of the whole system. Samples of forage DM mass and CP, ADF, NDF, and ash contents in each paddock of a rotational stocking system were collected monthly for 4 grazing seasons. Effects of month, stockpiling, hay feeding, temperature, precipitation, and durations of paddock grazing and rest on forage mass and quality measurements were investigated. The system was complex and dynamic; precipitation and rest days in particular showed clear interactions with both month and stockpiling when predicting forage mass and quality. Available DM, TDN, and CP were compared to nutrient density requirements for beef cows to conclude that the system met or exceeded requirements. Six years of production data from a spring-calving cow-calf enterprise that utilized rotational stocking and fall stockpiling were analyzed. Comparisons among 2 cow frame size and 2 calf creep system treatments for production efficiency (total weaning weight per land area), and net returns to the enterprise, were made. Pastures with medium frame cows and designated creep systems had the greatest production efficiency, but also had the highest costs and netted the least returns. Greatest net returns were achieved in large frame, forward creep systems, which had the lowest production efficiency but also the lowest costs. Provided the quality of calves produced is suitable for other phases of the production stream, we conclude that minimizing costs rather than maximizing productive outputs is a better focus for cow-calf enterprises faced with similar decisions among frame size and creep system treatments. / Ph. D.

The largest agricultural enterprise in the Appalachia region of Virginia is livestock production, particularly beef cow calf operations. However; topography and land holding patterns have resulted in a majority of small farms operating part time on less than 150 acres. These farms, while abundant, are not necessarily profitable. Management intensive grazing has been suggested as an alternative to traditional production practices to increase profitability. A profitability analysis was conducted by comparing a traditional style of cow-calf management where hay was produced on farm with a full machinery complement to a management intensive grazing farm where forages are stockpiled and all hay was purchased on farm, requiring minimal machinery investment. Four farms were simulated using Finpack Farm Management software by utilizing production data from the Virginia Tech Shenandoah Valley Agriculture Research and Extension Center and secondary financial data. The first two farms were listed as having a traditional style of management with hay production and two different stocking rates, 1.75 acres per cow-calf unit and 2.25 acres per cow-calf unit, respectively. Farm 3 and Farm 4 were simulated utilizing management intensive grazing and the two socking rates. It was found that while none of the farms actually show a profit the management intensive farms did outperform the traditional style farms. Farm 3 with the 1.75 acre per cow-calf unit stocking rate was the best performing farm financially. With these findings, beef cow producers will be able to make better management decisions and explore more profitable alternatives. / Master of Science

The objective of this trial was to evaluate the effect of a multi-strain probiotic on serum concentrations of selected metabolites in young calves. Holstein heifers (n = 112) from a commercial dairy were enrolled within 48 h of birth and placed into individual hutches. Calves were weaned at 60 d of age and remained in their hutches until 90 d of age, when they were moved to group housing. Calves were placed into 2 treatment groups: 1) control and 2) B. subtilis, B. lichenformis, L. animalis, and P. freudenreichii probiotic (Bovamine Dairy Plus, Chr. Hansen, Milwaukee, WI). Control calves received 0.5 g of lactose in milk once daily until weaning and 0.75 g in grain thereafter. Treatment calves received 0.5 g (1.1 × 10^10 cfu/g) probiotic in milk once daily until weaning and 0.75 g (1.65 × 1010 cfu/g) probiotic in grain thereafter. Jugular blood samples (6 mL) were collected at 14, 25, 45, 63, 77, 120, and 180 d of age for the determination of serum β hydroxy-butyrate (BHB), plasma glucose, non-esterified fatty acid (NEFA), total free amino acids (TFAA), blood urea nitrogen (BUN), and tumor necrosis factor-α (TNF). Data were analyzed as a mixed linear model to determine the fixed effects of treatment, day, and their interaction and also the random effect of calf. Single degree of freedom contrasts were used to evaluate the effect of phase (pre- vs. post-weaning) and the interaction of treatment with phase. Concentrations of BHB increased throughout the 180 d of the study and were greater (P < 0.001) in the post-weaning (661 μM) vs. pre- weaning (240 μM) phase and greater for the probiotic-treated calves in the post-weaning phase only (treatment × phase, P < 0.001). Glucose concentrations were greater (P < 0.001) for the pre-weaning (88.0 mg/dL) vs. post-weaning (81.1 mg/dL) phase and greater for calves receiving probiotics in the pre-weaning phase only (Treatment × phase, P < 0.01). Non- esterified fatty acid (NEFA) concentrations were greater (P < 0.001) in the pre-weaning vs. post-weaning phase and were greater in calves not receiving probiotics (treatment × phase, P = 0.0036).Serum TFAA concentrations were greater (P < 0.001) in the pre-weaning (3.37 mM) vs. post-weaning (3.03 mM) phase and greater for probiotic-treated vs. control calves (3.22 mM vs. 3.11 mM; P < 0.001). Concentrations of BUN were greater (P ≤ 0.001) in the post-weaning vs. preweaning phase and were higher for probiotic treated calves vs. control in the post-weaning phase (P < 0.001). Tumor necrosis factor-α (TNF) concentrations were affected by treatment (P< .001). Calves that received probiotic supplementation had lower TNF concentrations on day 63 of life when compared to control calves on day 63 of life. Data suggest that nutrient metabolism and ruminal development were enhanced by feeding a multi-strain probiotic.

This thesis examines the characteristics of dusky dolphin (Lagenorhynchus obscurus) nursery groups and ontogeny of dusky dolphin calves. Data were collected via boat-based group focal follows of nurseries from October 2006-May 2007. A total of 87 nursery groups were encountered. Data were analyzed according to age category (infant or yearling) and season (early or late). Nursery group membership was lowest in the early season and when yearlings were present. The average number of yearlings in a nursery group was less than that of infants. The predominant activity of calves was rest. Early infants rested the most, while travel seemed most important for late infants, and early yearlings were most likely to forage. With the exception of early infants, all calves were more likely than adults to interact with boats. When taking month into account, yearlings were more social in general than infants. Infants showed a positive trend in sociality, while yearling sociality remained relatively stable. Nursery groups are markedly segregated by calf age, and 80% of nursery groups contained calves of only one age group. Dusky dolphin calves show a similar trend in preference for position in relation to the mother as that in bottlenose dolphins (Tursiops sp.), with echelon swim decreasing with age. However, all calves appear to prefer echelon swim when nursery groups are traveling. Calves were more likely to swim independently in the late part of the season and while foraging or socializing, and were more likely to be in close proximity to their mothers while resting or traveling. Calves learned noisy leaps, followed by clean, coordinated, and acrobatic leaps, in that order. There was no clear relationship between behavioral state and types of leaps performed by calves. Early infants leapt less often than older calves, but leap frequency did not differ among the older calves. The overall pattern in the ontogeny of dusky dolphin leaps indicates that the physical development of leaps is learned individually, while the context in which the leaps are performed is learned from conspecifics. These results indicate that nursery groups represent an important environment for healthy physical and social development of calves.