A 2-year comparison of the production, health and fertility of dairy cows given concentrates either twice daily in the parlour or through out-of-parlour dispensers

Abstract

ABSTRACTMilk production, reproduction, blood composition and health were studied in two groups of British Friesian cows given food either twice daily in the parlour (IPF group) or through automatic out-of- parlour food dispensers (OOPF group) in the first 14 weeks of two consecutive lactations. The numbers of cows in the IPF and OOPF groups were 28 and 29 respectively in year 1 and 40 and 35 in year 2.There were no differences in milk production or reproduction in year 1 but in year 2 the OOPF group had significant proportional increases in the yield of fat (+0·079) and protein (+0·072) and the median time from calving to conception was reduced by 43·5 days. In the IPF group body condition score was lower than in the OOPF group in year 1 (2·27v. 2·59;P< 0·001) and in year 2 (2·37v. 2·57;P< 0·01); as were serum total protein (75·8v. 77·5 g/l;P< 0·05) and (73·9v. 75·8 g/l;P< 0·01) and plasma glucose concentration (215v. 2·32 mmol/1;P< 0·001) (2·28v. 2·42 mmol/l;P< 0·01). In year 2 only, serum urea was lower (5·52v. 6·07 mmol/l;P< 0·001) and serum copper higher (131v. 11·9 μmol/l;P< 0·001) in the IPF group; the activities of aspartate amino transferase (1·66v. 1·62 logmi.u. per 1;P< 0·05) and of glutamate dehydrogenase (1·00v. 0·70 logmi.u. per 1;P< 0·001) were higher, despite no significant difference in fat deposition in the liver. The only significant difference in the incidence of disease was fewer cases of mastitis in the OOPF group in the second year (21v. 12 cases).The similarity in concentrate intakes, together with higher concentrations of blood glucose and total protein and better condition score, indicate either a more efficient utilization of energy in the OOPF group or a lower consumption of forage in the IPF group. The increased activities of liver enzymes and the high serum copper coupled with the increased incidence of mastitis and poorer fertility may indicate the release of endotoxin following chronic lactic acidosis in the IPF group.