Effect of non-genetic factors on milk composition in Alpine goats
2001
Margetin, M. (Vyskumny Ustav Zivocisnej Vyroby, Nitra (Slovak Republic)) | Milerski, M.
The data from milk recording for the period 1995-1997 were used to analyse the effect of non-genetic factors of surroundings on the content of basic milk components in Alpine goats (AG). Linear models with fixed effects (SAS-GLM) were used. Extremely low or high average values of the content of fat (% f), proteins (% p) and lactose (% l) were excluded from the analysis. The effect of the factor herd (H), lactation order (LO), control year (Year), period and/or month of kidding (PK), number of sucking kids (NSK), associated variable HYP (H x Year x PK) as well as two concomitant variables on % f, % p and % l were evaluated. The analysis was performed with 533 to 615 lactations in dependence on the evaluated variable and used model of the covariance analysis. We found out that the factor H, Year and HYP has a statistically very significant effect (P0.001) on % f, % p and % l. The factor LO influenced significantly mainly % f, and factor PK % f and % p. The number of sucking kids did not influence significantly % f and % p. The average content of fat, protein and lactose represented 3.71%, 3.00% and 4.35% in the analysed population. Significantly higher content of fat (3.87%) was in goats in 1st lactation compared with goats in 3rd and 4th lactation (3.53% and 3.30%, resp., P0.05 and 0.01, resp.). The differences in % f, % p and % l of milk in goats with one, two or three sucking kids were nonsignificant in most of the cases. We found linear and quadratic effect of the concomitant variable "interval from kidding to 1st control measurement of milk" on % p
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