Abstract

The impact of a cow's live weight and body condition score (BCS) during pregnancy on the milking performance of a resulting daughter was investigated using 4,021 Jersey and 9,329 Holstein Friesian dam-daughter pairs from the Livestock Improvement Corporation Sire Proving Scheme. Although the estimated maternal heritability of each trait in each breed was small (< 0.02), a l kg increase in dam weight was associated with 1.19 (± 0.25) and 0.43 (± 0.15) litres increase in daughter milk volume, a 61 (±11) and 15 (±6) gram increase in fat and a 55 (± 8) and 14 (±5) gram increase in protein in Jersey and Holstein Friesian cows respectively. A one unit increase in BCS was associated with an increase in volume by 32 (± 19) litres in Jerseys and a 14 (± 14) litre decrease in Holstein Friesians. Fat increased by 1.91 (± 0.84) kg and 0.56 (± 0.55) kg and protein increased by 1.64 (± 0.63) kg and 0.06 (±0.42) kg per unit BCS in Jersey and Holstein Friesian respectively. All daughter responses are per lactation. Although small changes in the daughters milking traits were observed, the lack of significant variation in the maternal heritability indicates that the sample size of the dataset may not be sufficient to detect if prenatal maternal effects truly exist.

BW, Gudex, DL Johnson, and K Singh

Proceedings of the New Zealand Society of Animal Production, Volume 72, Christchurch, 19-22, 2012