Effects of individual versus pair housing on cortisol, growth, and health of dairy calves during the pre-weaning period

Authors: Pempek, Jessica; BYRD, JOHN - Purdue University; CRAMER, MARY - Colorado State University; METCALF, JESSICA - Colorado State University

Submitted to: American Dairy Science Association Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 3/17/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: In the dairy industry, it remains standard practice to raise pre-weaned calves individually. There is growing scientific evidence that housing calves in pairs or small groups largely benefits behavior, cognition, and productivity, but relatively few studies have investigated the impact of social housing on stress. The study aim was to investigate the effects of individual versus pair housing on cortisol, growth, and health of dairy calves during the pre-weaning period. Thirty Holstein-Friesian calves (18 females, 12 males) were enrolled into 1 of 2 housing treatments: individual (INDV; n=10 calves) or paired housing (PR; n=10 pairs; 20 calves). Calves were fed 3 L of milk replacer via bottle 2x/d until 49 of age, then 3 L 1x/d until weaning at 56 d of age. Data collection continued through 63 d of age. Hair samples were collected from the tail switch at birth, 35, and 63 d of age to assess hair cortisol concentration (HCC). All calves were weighed at birth and 56 d of age to calculate average daily gain (ADG). Calves were assessed daily for clinical signs of dehydration, depression, diarrhea, fever, navel inflammation, and respiratory disease, and lung ultrasounds were performed weekly to identify respiratory disease. HCC decreased significantly with age (Birth: 2.5± 0.1pg/ml; 35 d of age: 1.5±0.1 pg/ml; 63 d of age: 0.4±0.1 pg/ml), but we did not observe any evidence for differences among treatment groups in HCC. We found no evidence for a significant main effect of treatment on growth. However, there was marginal evidence for a treatment × sex interaction for weaning weight, whereby female PR calves were 5.8 kg heavier compared INDV female calves, and INDV male calves were 4.2 kg heavier than male PR calves. There was no evidence of any differences in clinical signs of disease or lung ultrasound scores between treatment groups throughout the study. These findings indicate PR housing did not adversely affect calf HCC or health. More research is needed to gain a better understanding of the potential differential effect of housing on male and female calves.