National Repository of Grey Literature 3 records found  Search took 0.00 seconds. 
Vliv výživy na mléčné složky u dojnic
Zmrhal, Vladimír
The individual components of milk are differently influenced by nutrition. Milk fat is the most impressionable component of milk. Its content is largely influenced by structure feeding ration and the amount of fibre in ration, acetic acid originates in which the fermentation as the main precursor of milk fat. Fat composition can be also influenced by feeding fats protected against degradation in the rumen and linseed or rapeseed seed which act to the content of unsaturated fatty acids. Negative effect on milk fat has mainly higher content of starch in feeding ration. Milk proteins are influenced by the amount of microbial protein synthetized in the rumen which is influenced by the ratio of degradable protein and energy feed. On the content of milk proteins act also so-called by-pass protein and nondegradable amino acids. Especially methionine and lysine, which are considered as limiting for the synthesis of milk proteins. The content of lactose is reduced when the organism is in the energy deficit and also by influence of mastitis. The aim of this work is to describe the mechanism by which nutrition act on dairy components.
Zhodnocení vlivů působících na mléčnou produkci a cenu mléka ve vybraných podnicích
Spáčilová, Kristýna
The Diploma thesis was dealing with the evaluation of the factors affecting the milk production and the price of milk in the chosen companies. The data was obtained online from the results of performance monitoring and results of encashment milk. The price data was obtained from company´s basic records. The dairy cows were divided according to lactations 1. to 4., where the parameters of milk production, content of fat and protein were evaluated. Furthermore, the average monthly milk price in both companies was monitored over three years. Finally, both companies were evaluated basing on their economic situation. Analyses were running in programs Microsoft Excel and Statistica12. All dairy cows of both companies met the breeding plan of their breeds. The lowest milk production was measured from dairy cows at first lactation. The highest milk production had dairy cows on the third to fourth lactation. When comparing the breeds, the Holstein breed was superior in milk production, but with lower content of milk components (fat, protein) comparing to the Czech fleckvieh breed. High-yielding cows of the Holstein breed were more susceptible to the temperature of the environment. The decline in milk production was coming with the arrival of autumn and summer months. The content of milk components was higher in the cold months due to a negative correlation with the milk production. Content of milk components was also likely to be affected by the heat stress and changes in nutrition.
Porovnání mléčné užitkovosti genotypů českého strakatého a holštýnského skotu chovaných ve stejných podmínkách
NOVÁKOVÁ, Hana
The basic prerequisite to the economic prosperity of an agricultural company specializing in dairy cows is maximum production of milk and, by extension, dairy by-products at minimal production costs. In order to achieve that it is necessary to have dairy cows with the potential to reach optimal dairy production in the conditions of the given agricultural company. The objective of this paper is to assess the effect of genotype, lactation sequence, and age of the dairy cow at first calving on the parameters of her milk productivity. Our monitoring was conducted at a company named CIZ-AGRO, a. s., Cizkrajov. For our analysis, we used productivity data measured from October 2012 to February 2015, during which the cows ended at least one lactation period lasting 240 305 days. These input parameters were collected from a total of 495 dairy cows that had ended a total of 997 lactations. The compilation of lactations was subsequently sorted out by genotype and lactation sequence, and thereupon by genotype and age of the dairy cows at first calving. Thus classified groups were assessed by average milk production, dairy fat, milk protein per lactation, and percentage content of fat and protein in their milk. The obtained results were thereupon subjected to a statistical analysis. The highest average milk productivity per lactation (9283 liters) was achieved by dairy cows in the group H100 that calved first at the age of over 27 months; the lowest milk (6239.2 liters) was recorded with a C100 heifer. In the group classified by lactation sequence, the differences were not statistically significant, the groups classified by the age at first calving, the differences were less significant statistically (P<0.05). Evaluation of the percentage content of milk components as well as the overall production of milk components per lactation in the group of lactations classified by genotype and lactation sequence, there were no statistically significant differences between the individual groups identified. In the group of lactations classified by genotype and age at first calving, the result showed less significant differences (P<0.05) between the group evaluated by total milk fat productivity and milk protein content per lactation. Monitoring the percentage content of fat in the milk in relation to the genotype and age of the dairy cow at first calving recorded medium level of statistically significant differences between the groups (P<0.01).

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