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Indicators of influence on the reproduction of the level and quality of milk production
Poláčková, Barbora ; Toušová, Renata (advisor) ; Petr, Petr (referee)
The aim of this study was to evaluate research of reproduction indicators on the level of milk production and the quality of the milk on selected farm. Materials for processing thesis were obtained on Oldřich Poláček´s Farm Hole. Mr. Poláček´s farm is located in Central Bohemia and manages 380 ha of arabe land. The farm bred Holstein cows, for now there are 190 dairy cows of this breed.
The indicators of milk production and reproduction were observed from 2013 to 2015. Results of the observed farm were compared with results of milk yield of Holstein cattle breeders association in the Czech Republic.
The data were analyzed and statistically processed using SAS 9.3 (SAS / STAT; 9.3, 2011). To determine the basic parameters of the files were used MEANS procedures and UNIVARIATE.
Evaluation of milk yield and indicators of reproduction was based on the results obtained from the recorded milk production of cows done by Holstein cattle breeders association and stable computer system AFIFARM. To evaluate the data were used 104 dairy cows, which had last two standardized lactation completed in the test years from 2013 to 2015 and 121 dairy cows, which had the first standardized lactation completed in 2014 or 2015.
For the milk yield were evaluated parameters of kilograms of milk per lactation, kilograms of milk per day, fat (%), protein (%) milk, depending on reproduction (days open, calving interval, age at the first calving) and lactation order.
Milk yield on the farm in 2015 was above the national average in Czech Republic. For dairy cows with the first lactation was up to 8 536 kilograms per standardized lactacion, for dairy cows with second lactation was up to 10 928 kg, and for dairy cows with third and more lactation was up to 10 864 kg. The average content of 3,71% fat and 3,28% protein.
The influence of lactation negatively impacted % protein (r = -0.278). Conclusiveness was on the significance level (P <0.001). The highest protein content was on the first lactation 3,40%, and lowest in the fifth lactation 3,20%.
Statistically failed to demonstrate the influence of the order of lactation on the milk yield per standardized lactation, kilograms of milk and % of fat content.
The positive effect was shown between milk yield per lactation in kg and daily milk yield in kg (r = 1). Conclusiveness was on the significance level (P <0,001). The lowest daily milk yield on the first lactation was (30,24 kg) with the production of 9223,06 kg of milk and the highest on the third lactation (47,43 kg) with the production of 14466,76 kg of milk.
Increasing of milk production per lactation had a negative effect on the % of fat content (r = -0,137), and % of protein content (r = -0.196). Conclusiveness was on the significance level (P <0.05). With increasing milk production declined % of fat content and % of protein content.
Statistically failed to demonstrate the influence of the milk production per lactacion on the open days and the calving interval.
Effect was demonstrated between the % of fat content and protein content in % (r = 0,501) at a level of significance (P <0,001). With increasing of fat content in%, increased also the the protein content in %. The lowest protein content (3,20%) was with a 3,66% of fat content. The highest protein content (3,40%) was with a 3,68% of fat content.
Age at first calving of dairy cows negatively impacted on % of the fat content of milk (r = -0,186). Conclusiveness was on the significance level (P <0,05). With age increasing at first calving declined % of fat content in milk.
There was also demonstrated a connexion between the standardized lactacion and days open (r= 0,227). Conclusiveness was on to the level of significance (P <0,05). With open days increasing the amond of milk per lactacion was higher.
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