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Vliv délky laktace na mléčnou užitkovost holštýnských dojnic
Pilch, Gustav
Abstract The evaluation of the influence of the length of lactation to the milk yield and milk components of Holstein milkers was carried out in four yield testings. Approximately 1000 samples were analyzed. The rated milkers were in different lactations and were divided into five groups expressing the number of lactation days. Milkers included in the 100-day lactation length group had significantly the highest average daily milk yield and the highest lactose (%) content, and also had the lowest average fat (%) and protein (%) values. With prolonged lactation duration, it has been found that the average daily milk (kg) yield and lactose (%) content decrease and fat (%) and protein (%) levels increase. The duration of lactation did not affect the urea level and the number of somatic cells in the milk.
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Změny v množství a složení mléka holštýnských dojnic způsobené prodloužením laktace
Čunderle, Jan
ABSTRACT The aim of the thesis was to evaulate and analysis of changes in the amount and composition of cow milk from Holstein dairy cows caused by prolonged lactation.The necessary information regarding the composition of cow's milk and a more detailed description of the milk components (fat, protein, somatic cell, lactose, urea) are included in the literature review. Samples were obtained from Holstein dairy cows from Unčovice Farm and used in our analysis. The samples were collected in the annual period from 7. 3. 2018 to 7. 3. 2019. The sampling was carried out by trained staff from the performance control and number of dairy cows involved in the analysis was 4540 units. The samples were taken for studied parameters (daily milk yield, fat content, protein content, lactose content, urea content and somatic cell count). The results show a large effect of lactation days on daily milk yield and and the content of milk components. Also, the daily milk yield is correlated with the content of milk components. The established results also show the effect of lactation on somatic cell counts but the effect of lactation on the urea content was not found. Furthermore, it was evaluated the frequency of mastitis.
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Vliv délky laktace na tržní produkci mléka dojnic českého strakatého plemene skotu
Kopřivová, Šárka
This Bachelor's thesis applies to the influence of the length of lactation on the market production of dairy milk by Czech Pied Cattle. Research took place in the farm Brťov-Lipůvka in Czech Pied Cattle. The outcome is that from the total number of 194 milk-cows, 31 (16 %) milk-cows had a prolonged lactation (306 and more days) and 163 (84 %) milk-cows with a normal lactation (up to 305 days). The results of the prolonged lactation analysis show that together with the growth of the lactation days, the followed parameters (such as content of fat and protein, production of milk) apparently change their values. These changes than reflect in daily average sales. The highest values of the sales happen in the beginning of prolonged lactation (CZK 107,6) while the lowest values happen within the middle period of the prolonged lactation (CZK 83,0). It was also found that the sequence of lactation did not have any impact on the ratio of the prolonged lactations. Based on the results we can observe that the milk-cows with a prolonged lactation are not able to reach the daily average sales that are required in order to cover the daily expenses, where the average daily loss per one milk-cow is CZK 15,9.
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