Effects of Individual and Pair Housing of Calves on Short-Term Health and Behaviour on a UK Commercial Dairy Farm

Abstract

Social pair housing of calves has previously demonstrated positive impacts for calves, so this study aimed to compare the health and behaviour of calves kept in individual compared to pair housing on a single commercial UK dairy farm. A total of 457 Holstein and Jersey heifer calves were recruited and systematically allocated to individual and pair housing. Weekly visits were conducted up to 8 weeks of age, with weight and presence of clinical disease measured using both a standardized scoring system and thoracic ultrasonography. A subset of calves (n = 90) had accelerometers attached to monitor activity, with CCTV placed above a further 16 pens to allow behavioural assessments to be made via continuous focal sampling at 1 and 5 weeks of age. During the study, there was a mortality rate of 2.8%, and an average daily liveweight gain (ADLG) of 0.72 kg/day, with no significant effect of housing group (p = 0.76). However, individually housed calves had increased odds of developing disease (OR = 1.88, p = 0.014). Accelerometer data showed that housing group had no effect on lying times, with a mean of 18 h 11 min per day (SD 39 min) spent lying down. The motion index was significantly higher in pair-housed calves (F1,83 = 440.3, p < 0.01), potentially due to more social play behaviour. The total time engaged in non-nutritive oral behaviours (NNOBs) was not impacted by housing group (p = 0.72). Pair-housed calves split their time conducting NNOBs equally between inanimate objects and on their pen mates’ body. Individually housed calves spent significantly more time with their head out of the front of the pen (p = 0.006), and also engaged in more self-grooming than pair-housed calves (p = 0.017), possibly due to a lack of socialization. The overall findings of this study indicate that within a UK commercial dairy management system, pair-housed calves were healthier and more active than individually housed calves, while housing group did not influence ADLG or the occurrence of NNOBs.

Effects of the Individual and Pair Housing of Calves on Long-Term Heifer Production on a UK Commercial Dairy Farm

“…There was a significant association with birthweight, such that heavier birthweight calves had an increased DLWG between weaning and conception. This trend has been noted by others in pre-weaning calves [ 13 , 16 , 52 ], with this study demonstrating that the trend continues following weaning. This may be linked to physically larger calves having an increased ability to compete for food and to ingest larger meal sizes than physically smaller calves.…”

“…Out of all the calves enrolled, a total of 141/431 (32.7%) experienced disease between birth and weaning [ 13 ]. Of the heifers surviving to weaning, a further 273/418 (65.3%) experienced at least one case of disease between weaning and the end of the first lactation (134/418 prior to the first insemination and 139/418 between the first insemination and the end of the first lactation) ( Table 2 ).…”

“…A total of 431 of the Holstein heifer calves were recruited at birth from March to December 2020. Details of the pre-weaning management are given in Mahendran et al [ 13 ]; in summary, calves were systematically allocated to either individual or pair housing, which consisted of pens within sheds formed from prefabricated plastic dividers (Calf-Tel Pen system, Hampel Corp, Germantown, WI, USA), with internal dimensions of 122 cm × 213 cm for an individual pen and twice this for a pair pen. Calves were fed 6L of milk replacer per day (24% whey protein, 20% fat), ad libitum starter pellets (18% crude protein, 4% fats, 12% crude fibre) and had ad libitum water access.…”

“…A total of 431 calves were initially recruited at birth into the study over a nine-month period, with 13 calves dying during the pre-weaning period and being excluded from further analysis (a 3.0% pre-weaning mortality rate). Full analysis of the pre-weaning data is presented in the paper by Mahendran et al [ 13 ].…”

“…Disease prevalence in calves can be affected by housing type, such that individually housed calves either experience higher disease levels [ 13 , 14 , 15 ] or no difference in disease prevalence compared to individually housed calves [ 16 ]. Calf disease can reduce growth rates during the rearing period [ 17 ], especially up to 6 months of age [ 18 ], possibly due to disease immune responses creating a large bio-energetic challenge [ 19 ] as well as potentially reducing feed intakes [ 20 ].…”