The aim of study was to evaluate the growth indicators in total of 1,986 purebred Charolais calves in relation to the sex, year of birth, birth season of the calves and also dam´s parity. At the same time, the object of work was to evaluate cows' longevity. We found higher values of live weight in bulls (P>0.05), the occurrence of twins showed lower birth weight (P<0.001) and weaning weight (P>0.05). The spring season of calving had an influence on lighter offspring in birth weight (P<0.001) as well as in pre-weaning period (P<0.001); the heaviest calves were born in the winter calving season. Calves born to primiparous cows were markedly lighter at birth (P>0.05), at the age of 120 days (P>0.05), and also at the weaning (P<0.05) than those born to older cows. The linear model characterized by the coefficient of determination for all fixed effects was R 2 = 0.714862% for birth weight (BLW), R 2 = 0.375164% for weight at 120 days (LW120) and R 2 = 0.473550% for weaning weight (LW210). On the basis of the results, we can observe the increased growth performance of calves over the years, pointing to the adaptation of Charolais to conditions in Slovakia.
The aim of the study was to evaluate the changes of fat-to-protein ratio (F/P ratio) from early to mid-lactation and the impact on milk yield. 208 Holstein cows from 3 dairy farms in west Slovakia calved between years 2012 and 2015 were observed. Into the study 908 test-day records of milk yield were included. Cows were from 5 to 150 days in milk (DIM). Statistical analysis and analysis of influence of F/P ratio on milk yield were performed by SAS. The sample of observed cows produced 35.25 ± 11.55 kg*day -1 of milk. The average day in milk was 77.40 ± 41.17 and the average F/P ratio was 1.19 ± 0.25. In acidosis risk were 19.71% of all observation and 8.92% were in ketosis risk. The occurrence of acidosis risk increased and the occurrence of ketosis risk decreased from early to mid-lactation. The model described the variation of milk yield by 44.20%. All of the selected effects except the year of calving had high statistical significant (P<0.01) influence to variation of milk yield. The effect of F/P ratio decreased the milk yield by 4.97 kg*day -1. The highest impact of F/P ratio was observed between 5 and 30 DIM and decreased the milk yield by 6.31 kg*day -1 . The average F/P ratio of observations between 5 and 30 DIM was 1.32 ± 0.30. The smallest impact of F/P ratio was found between 61 and 90 DIM and decreased the milk yield by 3.74 kg*day -1 . The average F/P ratio of observation between 61 and 90 DIM was 1.16 ± 0.22. It is possible to use F/P ratio as non-invasive indicator of metabolic status to decrease the negative impact to milk yield. . Priemerná hodnota pomeru tuku a bielkovín medzi 61 až 90 dňom laktácie bola 1,16 ± 0,22. Pomer tuku a bielkovín je možné použiť ako neinvazívny ukazovateľ na zníženie negatívneho dopadu metabolického stavu na mliekovú úžitkovosť.Kľúčové slová: pomer tuku a bielkovín, holštajnské kravy, metabolická porucha, kontrolný deň
The aim of study was to analyse the reproduction and factors affecting on reproduction traits of dairy cows in population of Slovak Spotted cattle from 2007 to 2016 the results for 37,274 dairy cows: days to first service (DFS), days open (DO), number of inseminations per conception (NIC), age of first calving (AFC) and calving interval (CI). The basic statistical analysis were analysed using the SAS version 9.3. For the actual computation a linear models with fixed effects was used: For the actual computation a linear models with fixed effects was used: yijklm = μ + HYSi + BTj+ Fk+ Bl +eijklm. The linear model represents coefficients determination R2 = 0.452117% (P < 0.001) for DFS, R2 = 0.377715% (P < 0.001) for DO, R2 = 0.348442% (P < 0.001) for NIC and R2 = 0.317128% (P < 0.001) for CI with all fixed effects. Correlation coefficients among DFS with DO, NIC, AFC and CI were r = 0.37275, r = -0.06881, r = 0.06493 and r = 0.08348. These coefficients were highly statistically significant (P < 0.001).
The aim of this study was to evaluate lactose in relation to milk production and calving interval in dairy cows of Slovak Spotted cattle. A total of 92,730 lactations from 45,800 dairy cows evaluation from 2015 to 2019 were used for investigating lactose percentage (LP), milk yield (MY), lactose yield (LY), fat percentage (FP), proteins percentage (PP) and calving interval (CI). Data were analysed using the SAS version 9.4 and linear model with fixed effects: herd-years-season (HYS), sire (S), breeding type (BT), coding of milk (Cod-MY) and coding of calving interval (Cod-CI). In the dataset the average of LP was 4.77 ±0.20%, while the one of MY, LY,
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