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Based on data obtained using T4C herd management software from three farms equipped with milking robots, analysis was made of the effect of herd, age of cows, stage of lactation and milk production level on the number of visits to the milking robot and the proportion of different numbers of these visits. GLM and FREQ procedures of the SAS package were used for statistical analysis. The visits ended with 3.0 milkings and 2.6 refusals on average. The number of visits ending with milking decreased with advancing age and lactation, and increased with increasing milk production level. Among primiparous cows, 48% of the cows milked 3 times and 28% of the cows milked 4 times a day. Among multiparas, most cows milked 3 times (39%) and 2 times a day (37%). Most of late lactation cows (56%) milked twice, and in the other groups three times daily milking formed the largest proportion (around 45%). Considerable differences were found in the milking frequency depending on milk production level: among lowest yielding cows (≤ 20 kg milk) as much as 58% milked twice, and among highest yielding cows (≥ 50.1 kg milk) as much as 55% milked four times. The relatively high proportion of 5 refusals among the highest yielding cows (18%) and also among cows until 251 days of lactation (23-33%) should direct breeders’ attention to the proper balancing of diets for these cows.
The aim of the present study was to determine a relationship between the somatic cell count in milk and daily yield, chemical content as well milk technological usefulness in different breeds cows. The examinations included a total of 1 867 milk samples collected from cows of four breeds: Polish Holstein-Friesian, Black-White variety – 712 and Red-White variety – 356, Simental – 587 and Whitebacks – 212 samples. Each sample was examined to determine somatic cells count (SCC), basic chemical composition, thermostability and rennet milk coagulation time. Based on the SCC score, within each cow breed, the milk samples were classified into one of four groups, i.e. I – up to 200,000 cells/ml, II – 200,001-400,000 cells/ml, III – 400,001-1,000,000 cells/ml and IV above 1,000,000 cells/ml. The increase in SCC was associated with the reduction in daily milk yield of the high-yielding dairy cows. As far as milk composition is concerned, an increased SCC level was connected with raise in a total crude protein content and a distinct reduction in lactose level (P≤0.01) as well as with a small (P≤0.05) increase in fat and casein content, and elevation in protein to fat ratio. The time of milk enzymatic coagulation also was lengthened (P≤0.01) but it did not influence its thermostability. The significant relationship (breed x SCC) for the protein, casein and lactose content, protein to fat ratio as well as rennet milk coagulation time has been revealed.
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