COMPARATIVE-EXAMINATION OF RUMEN DEVELOPM ENT, FATTENING PERFORMANCE AND CARCASS QUALITY IN VEAL CALVES FROM NATURAL MATERNAL REARING OR CONVENTIONAL BUCKET-FEEDING

The influence of rearing method on rumen development, fattening perfor mance and carcass quality was tested in 10 German Black and White Pied bull calves divided into two groups. After a single natural suckling, 5 carves were reared by bucket feeding up to the 90(th) day and there after fed on hay and concentrates. The other 5 calves remained with th eir mothers. Slaughter of both groups was carried out on 165(th) day. The daily live-weight gains of the calves were 1355 g (p less than or equal to 0.001) m naturally suckling and 1082 g in bucket-feeding. The slaughter yield of the calves from the naturally suckling group was 6 3.1 % (p less than or equal to 0.001) compared to 55.5 % for conventio nal bucket-fed calves. Naturally suckling calves had an Intramuscular fat content of 0.9 % (p less than or equal to 0.001) while bucket-fea calves had only 0.5 8 fat. In suckling calves. the pH values measured in rumen (6.3, p less than or equal to 0.01) and small intestine (6.7, p less than or equal to 0.05) were significantly lower and the pH in the abomasum (3.4, p less than or equal to 0.001) was significantly hi gher than values obtained from bucket-fed calves (6.9/7.7/2.4). No dif fer ences between total intraruminal concentrations of volatile fatty acids in animals of either group were detected. Rumen villi and rumen musculature in the naturally suckling calves were poorly developed in comparison to bucket-fed animals. The total rumen weight (3114 g to 49 36 g, p less than or equal to 0.001) and rumen volume (17.2 1 to 27.4 1, p less than or equal to 0.01) were also significantly lower. This r esulted in decreased rumen activity and reduced fermentation rate in t he naturally suckling group even though these animals were able to sup plement their milli diet with the corn silage fed to the mother cows. Without this possibility, these deficiencies of rumen development in t he naturally suckling calves may have been even more pronounced. Ongoi ng experiments are designed to determine whether the differences obser ved between the calves produced by these two holding methods persist i n the period after weaning. Of specific interest is the question of wh ether the precocious development of the rumen in bucket-fed calves is advantageous during the period immediately after weaning or whether th e superior preweaning. performance of the naturally suckling calves gr oup over that of bucket-fed calves is significant at slaughter in the age of 14 month.