A total of 506 samples of bulk tank milk from morning and evening milkings were analyzed to assess the milk rennet-coagulation ability. Data from the following dairy breeds reared in 55 herds of Trento province, were available: Holstein Friesian (8 herds), Brown (16 herds), Simmental (10 herds), Rendena (13 herds) and Alpine Grey (8 herds). Minimum and maximum number of samples per herd was 4 and 12, respectively. Traits analyzed were: coagulation time in minutes (R), curd-firming time in minutes (K20) and curd firmness in millimeters (A30). Mean and standard deviation for R, K20 and A30 was: 15.90 ± 3.26, 6.13 ± 2.52 and 24.03 ± 6.95, respectively. Analysis of variance was performed using a GLM procedure (SAS package) in order to study the effect of the following sources of variation: breed, herd, recording season, class of milk yield, fat and protein percentage, acidity, urea, bacterial count, clostridia contamination, somatic cell count, herd average days in milk and herd average age at calving. Breed resulted one of the most important sources of variation analysed; other results will be discussed.
Sources of variation of milk rennet-coagulation ability of five dairy cattle breeds reared in Trento province
DAL ZOTTO, RICCARDO;GALLO, LUIGI;CARNIER, PAOLO;CASSANDRO, MARTINO
2003
Abstract
A total of 506 samples of bulk tank milk from morning and evening milkings were analyzed to assess the milk rennet-coagulation ability. Data from the following dairy breeds reared in 55 herds of Trento province, were available: Holstein Friesian (8 herds), Brown (16 herds), Simmental (10 herds), Rendena (13 herds) and Alpine Grey (8 herds). Minimum and maximum number of samples per herd was 4 and 12, respectively. Traits analyzed were: coagulation time in minutes (R), curd-firming time in minutes (K20) and curd firmness in millimeters (A30). Mean and standard deviation for R, K20 and A30 was: 15.90 ± 3.26, 6.13 ± 2.52 and 24.03 ± 6.95, respectively. Analysis of variance was performed using a GLM procedure (SAS package) in order to study the effect of the following sources of variation: breed, herd, recording season, class of milk yield, fat and protein percentage, acidity, urea, bacterial count, clostridia contamination, somatic cell count, herd average days in milk and herd average age at calving. Breed resulted one of the most important sources of variation analysed; other results will be discussed.
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