The effects of long haul transport on pregnant, non-lactating dairy cows

Abstract

dAims. The transport of dairy cows from the North to the South Island of New Zealand has been common in recent years. The aims of this study were to determine the serum biochemical and bodyweight responses of cows to such a journey, and to investigate the effects of pre-transport hay feeding. dMethods. Pregnant, non-lactating Jersey cows from two herds were transported by road (1196 km) and ferry (5 hours) over a 3–4 day period. Cows in each herd were allocated to three 4-day pre-transport feeding treatments (grass only, grass + hay, 3 days of grass then 1 day of hay). Twelve experimental cows selected from each treatment group were weighed and blood sampled before transport, on arrival, and 24 and 48 hours after arrival. Additional blood samples were collected from experimental animals in one herd before and after one of the overnight rest stops during the journey. Sera were analysed for serum betahydroxybutyrate, total protein, calcium and magnesium concentrations and creatine kinase (CK) activity. dResults. Cow bodyweights declined by 6 -–9% during the journey and although they increased after arrival, they were still lower (p < 0.001) than pre-transport values 48 hours after arrival. Serum magnesium fell (p < 0.001) from pretransport concentrations of 0.95 mmol/l (Herd 1) and 0.83 mmol/l (Herd 2) to mean values of 0.50 mmol/l for both herds after transport. Total protein and CK concentrations increased during the first day of transport in Herd 2 cows, but then declined during the subsequent overnight rest stop. Pre-transport feeding treatments did not consistently affect cow bodyweight or blood biochemical responses to transport. dConclusions. Transported cows benefited from overnight rest, feeding and watering in terms of hydration and muscle status, but bodyweight and serum magnesium concentrations were significantly reduced by the overall journey, emphasising the requirement for suitable mineral supplementation and careful feeding and selection of pregnant cows before longhaul transport.