The influence of some nutritional factors on the incidence of the repeat breeder syndrome in high producing dairy herds

Abstract

Data on feeding and the incidence of reproduction disorders in dairy cattle were collected and compared between 2 groups composed of 6 Kibutz dairy herds each. One group contained herds picked at random from dairies with a good overall conception rate (45% and above according to rectal pregnancy examinations) and the other group was randomly selected from those with a low overall conception rate (32% and below). The two groups differed significantly in the incidences of repeat breeder cows (5.48% and 27.35%, respectively), the percentage of problem cows not pregnant 150 days after parturition (14.62% and 38.8%), days to conception (98.5 and 113.7 days), percentage of cows culled due to infertility (5.6% and 15.33%), and in the feeding practices. During the first half of lactation (the high production period) the differences occurred in the amount of digestible protein (11.9% and 9.9% of total dry matter) and in the amount of roughage (33.5% and 20.3% of total dry matter) fed. During the second half of lactation the significant differences between the 2 groups were in the energy level (16.5 F.U. and 13.6 F.U.) and digestible protein fed (10.25% and 8.73% of total dry matter), as well as in the total dry matter fed (17.7 Kg and 15.1 Kg). In the dry period, the only significant difference was in the total dry matter fed (12.7 Kg and 10.5 Kg). It appears that the incidence of repeat breeder cows is influenced by nutritional factors, particularly by the roughage, protein, and energy levels. Proper amounts of these three constituents in the ration during the entire inter-valving period is essential for providing appropriate fertility levels in high producing dairy herds.