Effect of restricted suckling on physiological and behavioural stress parameters in dual-purpose cattle in the tropics

Abstract

The present study evaluated the effect of restricted suckling (RS) on some physiological and behavioural stress measures compared to artificial rearing (AR). Thirty Holstein × Zebu cows and their calves were randomly assigned to one of two treatments. Cows were milked once daily. All calves were tethered in front of their dams during milking permitting physical contact between them in order to stimulate milk ejection, starting at 5 days of age. Calves in the RS treatment were allowed to suckle during 60 min daily, 30 min after milking and 30 min in the afternoon, while calves in the AR treatment were fed milk from teat bottles at the same times. Data were collected from day 4 to day 9, while treatments started on day 5. Heart and respiratory rates, body weight and temperature were measured (in that order) 15 min before entry into the milking parlour. Blood samples and pedometer readings were collected about 50 min later, immediately on return to their home pens. Higher heart rate in calves was found in the RS group than in the AR group. However, cortisol concentration was higher ( P < 0.05) in the AR than in the RS group. No difference was found in average weight gain, milk consumption, number of steps counted, body temperature and respiratory rate in RS and AR calves. AR induced significantly ( P < 0.05) higher level of serum cortisol concentration in the cows than did RS. No difference ( P > 0.05) was found in body temperature, heart and respiratory rates in RS and AR treatments. It was concluded that suckling and nursing reduces some stress parameters in calves and cows in the AR treatment.