Differences among and within crossbred beef cow groups in body condition and live weight

C.A. Morris, N.G. Cullen; P.A. Carson, G.A. Morley

Ruakura Animal Research Station, Ministry of Agriculture and Fisheries, Hamilton and Goudies Block, Department of Lands and Survey, Reporoa

Proceedings of the New Zealand Society of Animal Production. 1985, 45: 167-170

Data on live weight (LW) and condition score (CS) were collected in a large scale breed evaluation at Goudies (Department of Lands and Survey, Rotorua). The LW data were obtained 4 times a year; the CS data on a 1 to 10 scale similar to the Ellinbank scale (10 fattest), were obtained on 7 occasions from April 1982 to February 1984. Seven breed groups, 5 2-breed crosses and 2 straightbreds (Angus and Herefords), were compared. The crosses were Hereford-Angus (HA, including its reciprocal), South Devon-Angus (Sd.A), Friesian-Angus (FA), Friesian- Hereford (FH) and Jersey-Angus (JA).

Breed differences for LW and CS were reasonably consistent between years or seasons, in spite of large year effects and significant breed x age interactions. The CS means for JA, FA and FH were 0.9, 0.5 and 0.6 units less than for Angus cows, which in turn were 0.3 and 0.7 units lower than HA and Herefords respectively. The scores of Sd.A cows were near the average of the 7 groups together, but they were heaviest, being 22 kg above the herd mean.

It is suggested on the basis of this evidence that using the same target for LW or CS for different breed crosses is unrealistic.

Within breed and age groups, the correlation between August and November CS was 0.43. The equivalent figure for LW was 0.84. For each unit increase in CS, LW rose by 25.2 kg (r=0.53, range 0.42 to 0.60 on different recording occasions.

Keywords: NZSAPAB; Beef cows; body condition; live weight; crossbreds

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