a1 Hill Farming Research Organisation, Bush Estate, Penicuik, Midlothian, EH26 0PY
Body condition score, assessed subjectively on the live animal, was related to the directly determined body composition of 73 mature, non-pregnant, non-lactating cows of Hereford × Friesian, Blue-Grey, Galloway, Luing and British Friesian genotypes. Relationships between condition score and chemically determined body fat were all very highly significant, and considered to be of value for predictive purposes. Differences between genotypes in the proportion of fat stored in the main depots of the body resulted in differences in the relationship between condition score and body fat. British Friesian cows had a higher proportion of their fat in the intra-abdominal depots and the lowest proportion of subcutaneous fat, resulting in their being fatter at any given condition score. Hereford × Friesian cows had the highest proportion of subcutaneous fat and were thus the least fat at any condition score. One unit change in condition score was associated with a change of 2242 (s.e. 103) MJ of body tissue energy in Hereford × Friesian, Blue-Grey, Galloway and Luing cows and 3478 (s.e. 392) MJ in British Friesian cows. These figures may be used to bring a greater degree of precision to the nutritional management of beef and dairy cows.
(Received October 29 1982)
(Accepted May 22 1983)