Study of some linear type traits in relation with cow age and period lactation
2006
Petkov, P. (Trakijski Universitet, Stara Zagora (Bulgaria)) | Stoyanova, R. (Trakijski Universitet, Stara Zagora (Bulgaria))
The subject of study were 270 Bulgarian black and white cows from 5 farms. Cows were daughters of 60 bulls with survival to 3 rd lactation. Depending on stage of lactation the cows were grouped in four classes: to the 60 day - 53 number, from the 61 to the 120 day - 30; from the 121 to the 180 day - 27 and from 181 to the 240 day - 25 number. The aim of the present study was to examine relationship between ten linear type traits according to the age of the cows and the stage of lactation. The age of the cows significantly influence on fore udder attachment (FUA), udder depth (UD), teat length (TL), udder balance (UB) and rear legs rear view (RLRV). As cow's age progresses FUA from 29.3 to 24.8 (P0.001) while UD, TL and slop at the bottom of the udder increase (from P0.01 to P0.001). At the end of lactation FUA decreases (P0.001) and clearer udder cleft has been observed (P0.05).
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