Normal Growth of Dairy Heifers
Normal Growth of Dairy Heifers

Author: Charles Lloyd Burlingham

Publisher:

Published: 1914

Total Pages: 144

ISBN-13:

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The Federal Office of Farm Management reports (March, 1914) that there are 21,749,651 dairy cows in the United States. Considering the average productive life to be six of seven years, it is evident that 3,000,000 to 3,500,000 heifers must be grown each year to maintain the present number of dairy cows. The Government estimate of the cost of raising each to a productive age is $61.41. It therefore is important, not only that they be economically grown, but that they make such growth as will result in greatest production at maturity. A review of literature shows that little has been done experimentally on the growth of dairy cattle. While the scientific facts of growth have been worked out with man and with laboratory animals, almost no application of these facts has been made to the development of farm animals. The basis of this thesis is a study of growth of dairy heifers from birth to first parturition. The development of animals kept under different planes of nutrition is considered and compared with that made by those fed rations which are thought to be suitable for normal growth. From this data a standard of growth is calculated showing the size a heifer should attain at any particular age.

Nutrient Requirements of Beef Cattle
Nutrient Requirements of Beef Cattle

Author: Subcommittee on Beef Cattle Nutrition

Publisher: National Academies Press

Published: 2000-05-16

Total Pages: 249

ISBN-13: 0309069343

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As members of the public becomes more concious of the food they consume and its content, higher standards are expected in the preparation of such food. The updated seventh edition of Nutrient Requirements of Beef Cattle explores the impact of cattle's biological, production, and environmental diversities, as well as variations on nutrient utilization and requirements. More enhanced than previous editions, this edition expands on the descriptions of cattle and their nutritional requirements taking management and environmental conditions into consideration. The book clearly communicates the current state of beef cattle nutrient requirements and animal variation by visually presenting related data via computer-generated models. Nutrient Requirements of Beef Cattle expounds on the effects of beef cattle body condition on the state of compensatory growth, takes an in-depth look at the variations in cattle type, and documents the important effects of the environment and stress on food intake. This volume also uses new data on the development of a fetus during pregnancy to prescribe nutrient requirements of gestating cattle more precisely. By focusing on factors such as product quality and environmental awareness, Nutrient Requirements of Beef Cattle presents standards and advisements for acceptable nutrients in a complete and conventional manner that promotes a more practical understanding and application.

Animal Agriculture
Animal Agriculture

Author: Fuller W. Bazer

Publisher: Academic Press

Published: 2019-10-25

Total Pages: 560

ISBN-13: 0128170530

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Animal Agriculture: Sustainability, Challenges and Innovations discusses the land-based production of high-quality protein by livestock and poultry and how it plays an important role in improving human nutrition, growth and health. With exponential growth of the global population and marked rises in meat consumption per capita, demands for animal-source protein are expected to increase 72% between 2013 and 2050. This raises concerns about the sustainability and environmental impacts of animal agriculture. An attractive solution to meeting increasing needs for animal products and mitigating undesirable effects of agricultural practices is to enhance the efficiency of animal growth, reproduction, and lactation. Currently, there is no resource that offers specific knowledge of both animal science and technology, including biotechnology for the sustainability of animal agriculture for the expanding global demand of food in the face of diminishing resources. This book fills that gap, giving readers all the necessary information on important issues facing modern animal agriculture, namely its sustainability, challenges and innovative solutions. - Integrates new knowledge in animal breeding, biotechnology, nutrition, reproduction and management - Addresses the urgent issue of sustainability in modern animal agriculture - Provides practical solutions on how to solve the current and future problems that face animal agriculture worldwide

Nutrient Requirements and Utilization in Dairy Calves and Heifers
Nutrient Requirements and Utilization in Dairy Calves and Heifers

Author: Rodrigo Alfonso Molano Torres

Publisher:

Published: 2020

Total Pages: 238

ISBN-13:

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Dairy cattle replacement programs should provide management and nutrition that best supports the evolving needs of the developing heifer during all phases of rearing. The work described in this dissertation had two main objectives, i) to evaluate the supplementation of nutrients that could be limiting for dairy calves transitioning from the preruminant to the ruminant state, and ii) to quantify energy and protein requirements of the growing dairy animal. The first objective was addressed with two feeding trials evaluating what are considered limiting nutrients during the weaning phase. The first study tested the inclusion of different forms of methionine (Met), one rumen-protected and two different analogs (HMBTa and HMBi), in the calf starter. Calves fed the starter with HMBi consumed more feed postweaning and where heavier at the end of the study, but overall calves seemed not to be limited by Met. The second feeding trial assessed the effect of the combined supplementation of B-vitamins and choline on measures of performance and vitamin adequacy, and results suggested that dairy calves could obtain sufficient B-vitamins and choline from the diet and rumen synthesis to support growth rates over 1 kg/d. For the second objective, a database was constructed by merging eight comparative slaughter studies conducted on growing dairy cattle. Using this data set as input, a first analysis explored different aspects concerning nutritional energetics and generated new maintenance requirements coefficients, estimates of efficiency of ME utilization and predictive equations for energy retention for preruminant and ruminant dairy cattle. A variable efficiency of ME utilization for growth calculated as a function of feeding level offered the best prediction ability of energy retention. Finally, a subsequent analysis generated a system of equations to predict net requirements, true supply and efficiencies of use of N and AA for young preruminant dairy calves. Requirements were defined based on the supply of N and AA per Mcal from total ME and carbohydrate ME. A combined variable efficiency allowed the best prediction of N and AA balance on a net basis. Together both models improved the understanding on nutrient partitioning and enhanced the accuracy to predict nutrient requirements and utilization in growing dairy cattle.