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Effect of internal factors on milk production and quality
Zvonař, Miroslav ; Toušová, Renata (advisor) ; Stupka, Roman (referee)
The theoretical part of my bachelor's thesis was focused on describtion of milked breeds of cattle and its breeding technique and technology, as well as diet and feed. I was trying to expleain effect of some inner factors such as genetic factors, health condition, reproductive indicators, lactation number and mastitis, on milk production and its quality. In practical demonstration, held in the Meclovska zemědělská Ltd. company on the farm Srby, the influence of these inner factors on milk production and its quality was observed.
Firstly, the research was focused on milk constituents proportions: protein, fat percentage and the number of somatic cells. Secondly, it was focused on performance evaluation during normal lactation, the age of the cattle when first calving, meantime, insemination interval and post partum interval. Data were found in the cattle performance inspection results from January 2015 to December 2015.
On this particular farm Srby, there are circa 660 cows of the Holstein cow breed. In this reported period the average volume of milk was 10 400 kg during normal lactation with the percentage of proteins 3,44 % and 3,84 % fat. The average amount of somatic cells was 354 thousand in 1 ml of milk.
Randomly chosen group of 100 pieces of cattle was selected for further research. The group was divided into two groups of 50 pieces of cattle. In the first group there were 50 first calf cows and in the second group there were cows on the second or higher level of lactation. The first group of first calf cows managed to produce in average of 9 521 kg of milk with 3,86 % of fat and 3,36 % of proteins. The average amount of somatic cells in 1 ml of milk was 72 thousand. In the second group consisted of cows on second or higher level of lactation, there were different results as the average milk production was higher 11 790 kg with average of 3,75 % of fat and 3,35 % of proteins. There was significantly less somatic cells in 1 ml of milk. The result was surprisingly great with 46 thousands somatic cells in 1 ml of milk.
First calf cows during the first calving were 741 days old on average. The average insemination interval in the first group of first calf was 72 days long and the average post partum interval was 102 days long. In the second group of cows on higher lactation level the average meantime was 396 days. The average insemination interval was 80 days and the average post- partum interval was 117 days, which is quite long and it could be implying to bad result, but we should consider high efficiency of observed dairy cows.
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