K. Pabst, Lactation curves for renneting suitability of monozygous twin cows with different milk protein variants, MILCHWISSEN, 55(12), 2000, pp. 670-673
Renneting ability is regarded as a main parameter for the cheesemaking suit
ability of milk. Variants of kappa -casein and beta -lactoglobulin influenc
e renneting time, gelation time and curd firmness differently but significa
ntly. A number of papers deals with these aspects. What was actually not or
iginally shown are laction curves for these parameters. Effects of the mont
hs of lactation were previously obtained in studies of different cows in di
fferent months of lactation. This paper presents lactation curves of three
pairs of monozygous twin cows from the experimental farm at Schaedtbek with
the genotypes BB/AA, AA/BB and AB/AB for kappa -casein and beta -lactoglob
ulin, respectively. The results for weekly means indicate the advantage of
the BB genotype for kappa -casein in all three parameters even though the b
eta -lactoglobulin locus with the alleles AA was contradictory. The largest
day-to-day variation was measured for curd firmness which was independent
of the casein content. The year curves for the herd milk, including also th
e twin pairs, vary less than expected. They indicate that e.g. for manageme
nt purposes it suffices to measure cheesemaking suitability parameters four
times per month to attain adequate accuracy.