Milk coagulation ability of five dairy cattle breeds.
Samples of herd milk (506) were analyzed to assess sources of variation for milk coagulation properties (MCP) for 5 different dairy cattle breeds. Data were recorded in 55 single-breed dairy herds in the Trento province, a mountain area in northeast Italy. The 5 cattle breeds were Holstein-Friesian (8 herds), Brown Swiss (16 herds), Simmental (10 herds), Rendena (13 herds), and Alpine Gray (8 herds). Herd milk samples were analyzed for the MCP traits, milk rennet coagulation time (RCT), curd-firming time, and curd firmness (a30), as well as protein and fat percentages, somatic cell count, Soxhlet-Henkel acidity, and bacterial count. An ANOVA was performed to study the effect of breed, herd within breed, DIM, month of lactation, protein and fat percentages, somatic cell score, titratable acidity, and log bacterial count within breed on MCP. Breed was the most important source of variation. In particular, the Rendena breed showed the best MCP traits at 13.5 min and 27.0 mm for RCT and a30, respectively. The Holstein-Friesian breed had the worst coagulation properties at 18.0 min and 17.5 mm for RCT and a30, respectively. The other 3 breeds showed intermediate coagulation properties. The RCT values were better at the beginning of lactation, whereas RCT and a30 values were better in September and October (14.3 min and 25.7 mm, respectively). Among the composition traits, only the titratable acidity affected MCP traits of herd milk positively.
De Marchi
M
M
Department of Animal Science, University of Padova, Viale dell'Università 16, 35020 Legnaro, Padova, Italy.
Dal Zotto
R
R
Cassandro
M
M
Bittante
G
G
D000704:Analysis of Variance; D000818:Animals; D001947:Breeding; D002417:Cattle / Q000145:classification / Q000502:physiology*; D012085:Chymosin / Q000378:metabolism; D015169:Colony Count, Microbial; D003612:Dairying; D005223:Fats / Q000032:analysis; D005260:Female; D006863:Hydrogen-Ion Concentration; D016018:Least-Squares Analysis; D008892:Milk / Q000737:chemistry* / Q000166:cytology; D008894:Milk Proteins / Q000032:analysis; D013997:Time Factors
D005223:Fats; D008894:Milk Proteins; C025350:rennet; D012085:Chymosin