Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671
Performing Department
Population Health & Reproduction
Non Technical Summary
Most California dairy calves are raised in individual hutches which facilitate monitoring and handling of calves. However, housingcalves in single hutches typically restricts calves to very limited or no physical contact with other calves and prevents calves from expressing natural behavior such as social interaction and play. Previous studies showed that group housing is beneficial to calf welfare and is associated with an increase in dry matter intake and body weight gain. Nevertheless, several concerns hinder the adoption of grouphousing on California dairies, including increased transmission of disease due to increased calf-to-calf contact, and additional costs ofswitching from individual hutches to group housing.The aim of this project is to investigate the effect of modifying the current existing hutch systems to allow for the benefits of grouphousing of dairy calves in California while minimizing the costs incurred by the producers. Calves will be randomly assigned to 1 of 2treatments: (1) calves group housed at 3 calves per wooden group hutch (Tulare County) or plastic hutches with group exercise pen(Glenn County); (2) calves individually housed in wooden (Tulare County) or plastic hutches (Glenn County) until weaning. Body weight will be recorded at the start and end of the study. Hip height, chest girth, and health scores will be recorded weekly. The incidence of bovinerespiratory disease (BRD) and diarrhea will be scored using UC Davis BRD Scoring system. The results of this project could provideCalifornia calf raisers with a low-cost solution to access the benefits of group housing.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
The overall objective of this research is to determine whether group housing providing more space allowances will improve thewelfare and social interaction of dairy calves. The specific objectives are:1. Determine the effect of early group housing on behavior (standing, playing, social interaction, vocalization, and aggression),health indicators (morbidity, mortality, treatment and disease records), and growth (body weight, daily gain, body measurements)of dairy calves.2. Evaluate the effect of early group housing on the incidence of the most common diseases of young calves: diarrhea (scours) and bovine respiratory disease.
Project Methods
The study will be conducted in 2 locations in CA, Tulare and Glenn counties, in the spring to fall season which is known to be the greatest risk period for BRD in California (Dubrovsky et al. 2019). Before the start of the study, the total protein will be measured for all calves to control for status of passive transfer of immunity.In Tulare County, calves (bulls and heifers) will be assigned randomly to one of two treatments (balanced according to body weight, hip height, and chest girth upon entry) as follows: (1) calves individually housed in wooden hutch until weaning age (Individual; n = 21 pens; 21 calves); (2) calves group housed (n = 7 pens; 21 calves, 3 calves per wooden pen group hutch). The group hutches will be formed by modifying 7 conventional California wooden hutches (each with 3 individual units in its original form) where the middle two divider panels separating the 3 units will be removed. Hence, each group hutch will house 3 calves together. Panels will be removed at 7 days of age to allow for training calves on feeding from their own milk bottles during the first week.In Glenn County, calves (bull and heifers) will be assigned randomly to one of treatments: (1) calves individually housed in plastic hutches until weaning age (Individual; n = 21 pens; 21 calves); (2) calves group housed at 7 days old (n = 7 pens; 21 calves, 3 calves per plastic group hutch). The group plastic hutches will be formed by combining 3 run areas together by removing the fence in front of 3 individual hutches and surrounding them with one fence, so that each group of hutches includes 3 calves, 3 hutches, and one run. All of group house hutches will be provided with non-nutritive artificial teats for the reduction of cross-sucking (de Passillé, 2001). The behavior of calves (posture, eating, drinking, social interaction, play and aggressive behaviors) will be recorded by using instantaneous scan sampling method (Martin & Bateson, 2007) with the help of two observers. Calves will be weighed upon arrival and at the end of experiment to estimate average daily gain at end of trial. Hip height and chest girth will be measured weekly for all calves and calf treatment data will be recorded.The incidence of diarrhea and BRD will be determined using UC Davis BRD Scoring system (Love et al. 2014, 2016) on a weekly basis. Economic analysis, the cost of raising heifers during the pre-weaning period will be calculated for both systems (treatment 1 and 2; both dairies). Milk costs, labor for training the calves during the first 7 days, concentrate consumption, mortality, morbidity, and health treatments will be used in the economic model. California market prices for the inputs will be used following the methodology proposed by Hawkins et al. (2019).Statistical analysisThe sample size was determined using two-sample comparison of means with power= 0.8, and significance level = 0.05. The effect size was estimated based on (Abdelfattah et al., 2018). The minimum sample size was 20 in addition to 5% to account for loss follow up. A randomized complete block design with repeated measures using the mixed model procedure of SAS, with calf as the experimental unit. A linear mixed model with the fixed effects of treatment, week and the interactions of treatment × week will be fitted. The random effect will be calf nested within treatment.LimitationsOne possible limitation of this study is dominant calves consuming disproportionately more milk from other calves housed within the same group. Our previous experience with group housing is that calves need training in the first 7 days of life in the form of physical guidance and assistance. In our proposed study we will leave the divider panels for the first 7 days and if needed after that we will continue to provide the guidance and assistance to avoid calves consuming the other calves' milk allocation. In addition, we will use dummy teats (non-nutritive) to prevent cross-sucking.ReferencesAbdelfattah, E. M., Karousa, M. M., Lay DC Jr., Marchant-Forde J. N., Eicher, S.D. 2018. Short communication: Effect of age at group housing on behavior, cortisol, health, and leukocyte differential counts of neonatal bull dairy calves. J. Dairy Sci., 101(1):596-602.de Passillé, A. M. 2001. Sucking motivation and related problems in calves. Appl. Anim. Behav. Sci. 72:175-187.Dubrovsky S. A, Van Eenennaam, A. L., Karle, B. M., Rossitto, P. V., Lehenbauer, T. W., Aly, S. S. Epidemiology of bovine respiratory disease (BRD) in preweaned calves on California dairies: The BRD 10K study, J. Dairy Sci. 102:7306-7319.Hawkins, A., Burdine, K., Amaral-Phillips, D., Costa, J. H. C.. 2019. An Economic Analysis of the Costs Associated with Pre-Weaning Management Strategies for Dairy Heifers. Animals, 9, 471.Love, W. J., Lehenbauer, T. W., Kass, P. H., Van Eenennaam, A. L., Aly, S. S. 2014. Development of a novel clinical scoring system for on-farm diagnosis of bovine respiratory disease in pre-weaned dairy calves. PeerJ 2: e238; DOI 10.7717/peerj.238.Martin P., Bateson P. 2007. Measuring behaviour: An introductory guide. Cambridge Univ. Press, New York: p. 48-61. doi:10.1017/CBO9780511810893.006