Rf. Veerkamp et al., EFFECTS OF INTERACTION BETWEEN GENOTYPE AND FEEDING SYSTEM ON MILK-PRODUCTION, FEED-INTAKE, EFFICIENCY AND BODY TISSUE MOBILIZATION IN DAIRY-COWS, Livestock production science, 39(3), 1994, pp. 229-241
The objective of this study was to investigate genotype by feeding sys
tem interactions in Holstein-Friesian dairy cows. For this purpose, se
lection (S) and control line (C) cows, housed and managed at the Langh
ill Dairy Cattle Research Centre, were offered ad lib. complete mixed
diets, with proportions (in total DM) of concentrates, silage and brew
ers grains of either 20:5: 75 (LC) or 45:5:50 (HC), over a full lactat
ion. No significant feeding system x genetic line interactions were ob
served for a number of traits, describing milk production, feed intake
, efficiency and body tissue mobilisation, when compared as treatment
means (128 heifer lactations and 249 cow lactations). However, regress
ion coefficients of milk yield (P < 0.01) and condition score (P < 0.0
5) on pedigree index for fat plus protein yield were significantly dif
ferent between LC and HC. This indicates that G X E might become of im
portance in the future, with continued selection for fat plus protein
yield.