EFFECT OF DAILY EXERCISE ON PERFORMANCE, FEED-EFFICIENCY AND ENERGY-BALANCE OF TIED DAIRY-COWS

The effect of daily exercise on dairy cows was studied in 65 first and second calvers of the Swedish Red and White breed in a four-year expe riment, starting in July 1985. Half of the group walked outdoors 3 km/ day from May through October and 400-800 m/day from November through A pril. From July 1986 the distance walked in the summer period was 2 km daily. Daily exercise did not significantly affect voluntary DM intak e, the overall energy consumption or production of milk, ECM, fat or p rotein. The efficiency of milk energy and protein production did not d iffer between the treatments in lactations 2-4. Mean energy efficiency in these lactations was 5.6 MJ/kg ECM and mean protein efficiency 121 3 g AAT/kg protein. However, in lactation 1 and at restricted feeding, milk energy and protein production was significantly less efficient f or exercised cows than for non-exercised cows. The difference was 0.39 +/-0.12 MJ/kg ECM (p<0.01) and 132+/-28 g AAT/kg protein (p<0.001). Th e discrepancy between the Swedish standard for ME in milk production a bove maintenance, 5.0 MJ/kg ECM, and the results obtained in this and other recent studies are discussed. Concentrations of serum free fatty acids and plasma glucose were measured once a week in lactation weeks 1-8. No significant differences between the treatment groups were obs erved. Feeding was ad lib. in lactation weeks 4-12. It was noticed tha t the cows never lay down in the exercise area, which was covered with sand and soil. Behavioural disturbance in the form of tongue rolling was not influenced by exercise.