Tch. Miteva, T. Penev, Zh. Gergovska, J. Mitev, N.Vasilev, V. Dimova

Abstract. The study was performed at three dairy cattle farms from three districts in the country: Plovdiv, Bourgas, and Veliko Tarnovo. The cows housed at all three farms were of the Holstein-Friesian breed. A total of 150 cows were included, 50 from each farm. The rearing at the three farms was free with differences in some technological details. The following traits were recorded: hindleg conformation score examined from behind (HLCS), lameness score (LS), body condition score (BCS) of the cows. It has been established that by increasing the age (lactation number), the mean hindleg conformation score increased, respectively from 1.22 at the 1st to 2.29 at the 4th or following lactations. The cows with normal hindleg conformation (HLCS 1) had a mean lameness score of 1.13, which indicated that they did not have any major locomotory problems. The cows with the most considerable hoof overgrowth and change in the leg conformation score (HLCS 3) had the highest lameness score (2.33). The cows without locomotory problems (LS 1) had the highest mean BCS (2.54) compared to those with varying degrees of lameness. The cows with LS 3 had the lowest BCS (1.90). There was a tendency towards a lower extent of fattening in cows with locomotory problems. There were no significant differences in the mean values of HLCS and LS between the three farms, yet there was a difference in the percentages of cows with different scores. The causes can be found in the technological differences of rearing, feeding, etc.