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Vztah negativní energetické bilance a poruch reprodukce u dojnic
Drlíčková, Zuzana
This bachelor thesis focuses on excessive negative energy balance (NEB) in dairy cows, resulting from high milk yield, and its effects on reproductive performance. The aim was to present the principles of dairy cow nutrition, the occurrence, consequences, and monitoring of NEB and to describe the interrelationships with metabolic and reproductive disorders. In the practical part, the analysis of the dairy cows (n = 177) of Holstein cattle was carried out from 1 January to 30 June 2022. The reproductive technician evaluated reproductive disorders based on the veterinary examination and sonographic examination with a linear rectal probe. Of all monitored dairy cows, retained placenta was detected in 10,73 %, uterine inflammation in 31,07 %, follicular cysts in 16,38 %, and luteal cysts in 5,65 %. The prevalence of NEB was determined using individual milk samples collected as part of performance monitoring. Samples taken on days 5 – 30 after calving and days 31 – 60 after calving were used for the analysis. A statistically significant (p < 0,05) positive correlation was found for the observed milk components (acetone, beta-hydroxybutyrate, fat/protein ratio), and a statistically significant (p < 0,01) higher concentration in the first sample after calving compared to the second sample. For selected components, threshold values indicating risk of excessive NEB and ketosis were determined: acetone concentration ≥ 0,12 mmol/l, beta-hydroxybutyrate ≥ 0,10 mmol/l, and fat/protein ratio ≥ 1,3. When evaluating the first samples after calving, the values were exceeded on average in 48,77 % of the dairy cows and 31,64 % of the dairy cows in the case of the second samples. The fat/protein ratio was used to evaluate the relationship between NEB and reproductive disorders. The threshold value (≥ 1,3) indicating the risk of NEB was exceeded in 90 dairy cows, which, compared to healthy individuals, showed a higher incidence of the retained placenta by 5,28 %, uterine inflammation by 6,85 % and follicular cysts by 5,10 %. The analysis results showed a higher incidence of ovarian cysts connected to higher productivity (p < 0,01). In first-lactation dairy cows there was statistically significantly (p < 0,01) more intense NEB than in second-lactation dairy cows and the highest incidence of uterine inflammation. The results of the work demonstrate the connection between high productivity, NEB and reproductive disorders.
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Vyhodnocení efektu zavedení bolusu Kexxtone do bachoru dojnic na jejich výkonnost a zdravotní stav po otelení
LHOTA, Jiří
The aim of the diploma thesis was to evaluate the effect of the application of monensin in the form of intraruminal bolus Kexxtone before calving of cows on reproduction, performance and health status in the following lactation. Monitoring took place in the agricultural enterprise ZD Velká Chyška. Monitoring took place from the beginning of August 2022 to mid-March 2023. A total of 118 dairy cows were included in the monitoring. Approximately 3 weeks before birth, a bolus of Kexxtone was administered with body condition scoring, and at the postpartum check around day 7 after birth, blood was drawn from the subcaudal vein, also with body condition scoring. The following data were included in the monitored indicators: age at the 1st calving, order of the evaluated lactation, number of days during bolus administration before calving, BCS before calving, BCS after calving, lactation day at the examination, BHB value in blood, lactation day at the 1st heat , lactation day at the 2nd heat, lactation day at the 1st insemination, total number of inseminations, service period, lactation day at the 1st disease, number of diseases, lactation day at the peak of lactation, daily milk yield at the peak of lactation and milk yield in 100 days of lactation, lactation day on the control day, daily milk yield, % fat, % protein and ratio of fat and protein content in milk in the first 5 control days. Monitored indicators were sorted according to the order of lactation, bolus administration, BCS before calving, blood BHB level and the ratio of fat and protein content at the 1st and 2nd performance checks. In the group of cows that received a Kexxtone bolus, there was no positive effect on reproductive indicators, as their values were almost identical to the control group without bolus. The effect was not manifested even with the earlier occurrence of the 1st heat after calving. In cows that were given a bolus, a lower level of BHB was found in the blood after parturition, a different ratio of fat and protein content in milk was not found in the first controls after calving compared to the control, and a lower incidence of disease was recorded. Cows with bolus had a higher milk yield in the first 100 days of lactation by 142 kg of milk.
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Vliv tělesné kondice dojnic na hladinu ketolátek v krvi
BEŇASOVÁ, Veronika
The aim of this diploma thesis is to evaluate the data about holstein dairy cow body condition at calving and to review its effect on ketones blood level and its relation to incidence of ketosis. The monitoring took place in a selected dairy farm from October 2017 to February 2019. Body condition of 280 cows was evaluated on the day of calving by assessing the body condition score (BCS) and later on 10 days in milk the blood level of B-hydroxybutyrate was measured. Furthermore, parity, body weight in calving day, body weight on 10 days in milk, content of milk fat and protein on 10 days in milk and milk yield on 10 days in milk were monitored. Average BCS of the herd was 3,7, the maximum measured BCS value was 5, the minimum was 2. Total incidence of ketosis on herd level was 21,07 % considering ketosis if BHB 1,0 mmol.l-1. 62,7 % of that was a subclinical form of ketosis while the remaining 37,3 % was the clinical form of ketosis. Correlation analysis of the relation between parity and level of BHB in blood showed positive correlation (r=0,15, p=0,00), when cows on higher lactation had higher level of blood BHB. Positive correlation between fat/protein ratio in milk and level of BHB in blood was evaluated by correlation analysis (r=0,31 , p=0,00). The BCS at calving and BHB level on 10 days in milk showed positive correlation (r=0,14 , p=0,02). As far as negative energy balance is taken into account, the positive correlation between BCS at calving and body weight loss was confirmed (r=0,17 , p=0,00). The fact that heavier cows and cows with higher BCS mobilise more body fat reserves was confirmed by positive correlation between the body weight at calving and the body weight loss (r=0,47, p=0,00) and between the body weight at calving and the fat/protein ratio in milk (r=0,27, p=0,00). Body weight at calving had provable positive impact on the milk yield (r=0,19, p=0,00).
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