Author : Michelle Sarah Calvo
Release : 2012
Genre :
Kind : eBook
Book Rating : 514/5 ( reviews)
Book Synopsis Effects of Housing Strategies to Improve Calf Well-being by : Michelle Sarah Calvo
Download or read book Effects of Housing Strategies to Improve Calf Well-being written by Michelle Sarah Calvo. This book was released on 2012. Available in PDF, EPUB and Kindle. Book excerpt: The objectives of the research presented in this dissertation were to investigate current dairy calf housing systems and possible alternatives if similar California (CA) Proposition-2 type legislation were to be implemented on the dairy and beef industries. The prohibition of veal, gestational sow, and layer hen cage systems by CA Proposition 2 (2008 California general election; USDA, 2011) during the 2008 election had a large impact on the egg, swine, and veal industries in the state of California. Similarly, several other state ballot initiatives dictating housing conditions for confined livestock have passed with great success (Florida, 2002; Arizona, 2006; Oregon, 2007; California and Colorado, 2008; Michigan and Ohio, 2009; Maine, 2010; USDA, 2011), having more impact on the US egg, swine, and veal industries. Altogether, these legislative propositions will directly affect producers and the livestock industry of today and in the future. It is therefore advantageous and economically beneficial to producers for scientists to evaluate current and widely used housing systems to fully understand the beneficial and detrimental aspects of housing systems, and to achieve applicable creativity in designing systems that foster feasible advantages while diminishing the disadvantages.Respiratory diseases in calves are associated with the exposure of airborne pathogenic microorganisms, particulate matter (PM), and gases that compromise the defense mechanisms of the respiratory system. The bedding provided in calf housing structures (e.g., individual hutches) may increase the exposure of animals to the aforementioned air contaminants. Greater concentrations of airborne bacteria were observed for calves housed on bedded treatments compared to wooden slat flooring. Although the provision of bedding is known to supply calves with warmth and perceived comfort, the results demonstrated that calf exposure to greater concentrations of bacteria during the first two weeks of life may prime the calf immune system in a beneficial manner or cause infection and disease.Recent state ballot initiatives have brought the issue of space for livestock into question. California dairy calves typically are raised individually in wooden hutches with a space allowance (SA) of 1.23 m2/calf, and increased SA were evaluated to assess the impacts of space on measures of calf well-being, such as performance, health outcomes, and behavior. Calves with increased SA had greater body weights and average daily gains by 45 days of age, and calves with maximized SA had greater percentage of days with clean hides compared to calves with conventional and moderate increase in SA. Although there were no differences across treatments in clinical symptoms of respiratory illness, pulmonary Ovalbumin-specific IgE concentrations were lowest and advantageous for calves with moderate increases in SA compared to calves with conventional and moderate increase in SA. Calves with conventional and moderately increased SA had greater resting behaviors as they aged, but calf resting time for calves in maximized SA did not change over time. Additionally, modifying wooden hutches to the maximum SA did not enhance the calf innate immune function or rest duration of calves following castration. It appears that a moderate, rather than maximum, increase in SA may be more beneficial to the performance, resting time, respiratory antibodies, innate immune function, and well-being of calves. Calf housing systems that individually confine calves are widely used in the U.S. to inhibit competition for feed and reduce the transmission of disease between calves. Future legislation may mandate group housing for dairy calves without identifying suitable alternatives. When individual vs. grouped calves were evaluated in modified wooden hutches, individually housed calves spent more time in the resting-position than grouped calves. A greater percentage of days of clean hide scores were observed in individually vs. grouped calves; however, grouped vs. individually housed calves had greater days with nasal discharge, more efficient recovery from diarrhea, and lower, more beneficial concentrations of pulmonary Ovalbumin-specific IgE. The results observed in grouped calves suggest that early life microbial exposure may be beneficial to the respiratory antibody milieu later on in life. However, group housing entails social and behavioral aspects that do not protect calves from feed competition and resting duration, which is important to consider from a welfare perspective.These studies all improve the understanding of air quality inside wooden hutches, as well as the welfare trade-offs of increasing space allowance or group housing of newborn calves. There is a need for scientific knowledge, creativity, and collaboration to combat the current issues that drive evidence-lacking legislation today, especially on calf welfare. Together with innovative and sustainable approaches, the future of calf management and awareness and concern of animal welfare can be positively impacted.
