VOLUNTARY FEED-INTAKE IN HEIFERS - INFLUENCE OF BREED, AGE AND THE HAY CHARACTERISTICS

Voluntary feed intake was compared in heifers of different breeds: Holstein Friesian (diary breed), Montbeliarde (diary breed), Tarentaise (local dairy breed) and Salers (hardy breed). The animals were 1 or 2 yr old, except the Salers heifers which were only 1 yr old (table I); they were divided into 2 groups which were fed at libitum with hay of different qualities (table II). Organic dry matter digestibilities ranged between 48-62%. The heifers were housed in individual stalls, but some Holstein Friesian, Tarentaise and Salers heifers were also stabled in covered pens. Within breed, the variation in voluntary feed intake related to the body weight fell to almost-equal-to 77%. Within breed and within age the proportion was 58% (fig 1). In the 3 dairy breeds, feed intake increased with body weight raised to a power of 0.8 (fig 2). At the same body weight, the 3 dairy breeds had the same feed intake capacity (table III). Salers heifer intake was almost-equal-to 15% lower than that of the dairy breed. The quality of hay did not interact with breed for feed intake. In open housing, heifers ingested almost-equal-to 10% more than in individual stalls (table IV).