ABSTRACT:The objective of this study was to confirm the relationship among body condition score at the time around parturition, milk yield in subsequent lactation, reproductive efficiency and BCS development in Czech Fleckvieh dairy cows. The BCS and milk yield were measured once a month and the cows were divided into groups according to their BCS before and after calving. Next, data from the database of cattle reproduction of the Czech Fleckvieh herd book were used. The dataset was analyzed by multifactorial analysis of variance using procedures COOR and GLM of the statistical program SAS. Cows with lower BCS in the 1 st month after calving showed an increase in both milk yield and fat and protein corrected milk (FPCM) yield. No significant relationship was found between the BCS level before calving and subsequent milk yield. The body condition level in the last month before parturition influenced its subsequent decrease in the first phase of lactation. The group of cows with the highest BCS level before calving retained a high BCS level in the first five months of lactation. Adequately, the group of cows with the lowest BCS in the first month of lactation had the lowest BCS in the next four months. BCS before calving was not related to reproduction indicators, but the significant effect of BCS in the 1 st month after calving on the length of calving to the first service interval was confirmed. The group of cows with BCS > 3.5 in the 1 st month after calving had the most favourable reproduction indicators, also when the milk yield level was taken into account.

ABSTRACT:The objective of this study was to determine how non-nutritional factors such as herd, parity, days in milk, milk production, and milk components affect the concentration of milk urea. A retrospective, observational study comprising analyses of individual cow records from monthly dairy herd improvement milk tests including milk urea tests was conducted. Six commercial Holstein dairy herds were involved in the investigation from October 2000 to September 2003. The data were evaluated using the mixed linear model with repeated measures, and parameters were estimated by the REML method. Significant differences in milk urea concentrations were observed between herds (P < 0.0001), with a significant variability between test dates within herds. Significant effects of parity (P = 0.0003), days in milk (P < 0.0001), and their interaction were also found. Higher concentrations of milk urea were determined in the cows on the first and second parity (5.63 and 5.62 mmol/l, respectively) compared to the groups of cows on the third and fourth parity (5.47 mmol/l). It was found that milk urea concentration increased with the square of milk yield (P < 0.0001), while a negative quadratic relationship was found between milk urea concentration and milk fat % (P < 0.0001). It was concluded that milk urea concentration should be evaluated in association with days in milk, milk yield, milk fat %, and milk protein %.

ABSTRACT:The objective of this study was to determine how the concentration of milk urea (MU) and FPCM production affect reproduction in selected Holstein dairy herds in the Czech Republic. A retrospective, observational study comprising analyses of individual cow records from monthly dairy herd improvement (DHI) milk tests including milk urea (MU) concentration was conducted in six commercial Holstein dairy herds in cows that were bred from July 2000 to August 2003. A total of 1 333 cows with available breeding date, pregnancy status, and calving to first service interval from 31 to 150 days were selected. The data were evaluated using the mixed linear model and logistic analyses. The effect of MU concentration on the probability of conception at first service was not significant (P = 0.11). The results indicated a nonlinear relationship between MU concentration and the probability of conception. A significant effect of the length of calving to first service interval (P < 0.05) and FPCM (P < 0.05) was determined. The cows with the calving to first service interval longer than 2 months had higher probability of conception (10% higher). In the group with the highest FPCM a markedly lower level of successful pregnancy was determined (38.99%), which significantly differed from the group with average FPCM production (48.53%). The probability of conception at first service in the group with the lowest FPCM is at an average level (43.55%).

ABSTRACT:The objective of this study was to determine the dynamics and relative body weight (BW) changes after parturition and their relationships to milk yield in Holstein (H) and Czech Fleckvieh (F) cows, and also the relationships between their BW changes in the first 8 weeks of lactation and reproductive performance. A retrospective, observational study comprised analyses of individual cow records from a computerised herd management system. Production, body weight, and reproduction data were collected between December 2004 and February 2009 from F and H cows kept in a single experimental station. A total of 475 calving interval records (F: N = 132; H: N = 343) were included in the analysis. The data were evaluated using the mixed linear model with repeated measures, and parameters were estimated by the REML method. Whereas BW changes in F first-parity cows significantly (P < 0.01) differed from those detected in greater-parity cows during the major part of lactation, no such differences were manifested for H first-parity animals. The average BW change in weeks 1 to 8 was closely correlated with the BW change in the lactation week, with the lowest BW (NADIR) (r > 0.83, P < 0.0001) in both breeds. In H cows, the average BW change in weeks 1 to 8 and in NADIR significantly (P < 0.01) negatively correlated with the length of postpartum anoestrus, days between parturition and conception, days between first service and conception, and calving interval (P < 0.05 and P < 0.01, respectively). In F cows, the only significant correlations were those with days between parturition and first service (P < 0.05 and P < 0.01, respectively). It was concluded that BW changes postpartum might indicate reproduction problems particularly in H cows.Keywords: dairy cow; negative energy balance; body weight; milk yield; reproduction Negative energy balance (NEB) usually occurs in high-yielding dairy cows in early lactation when their energy expenditure is greater than their energy intake. NEB affects a number of physiological functions and especially reproductive performance of dairy cows after parturition. In order to ensure proper herd management and cows' reproduction, it is essential to estimate the extent and duration of NEB. Because of the difficulty of routine measuring the energy balance status, an indirect indicatorthe body condition score (BCS) -is used. Together with the BCS, the body weight (BW) of cows also changes during the period of NEB. It was concluded in earlier studies that the changes in BCS and those in BW are two different traits (Veerkamp and Brotherstone, 1997;Berry et al., 2002Berry et al., , 2007. A relationship exists between BCS, relative BW change in maximum NEB, and the reduced reproductive performance of cows (van Straten et al., 2009). The authors also concluded that the parameters characterising relative BW changes are better predictors of reduced reproductive performance than the measures of absolute BW changes and can be used to estimate the individual adaptation to NEB.

The aim of this study was to compare the metabolic status of dairy and dual-purpose cows kept in a single herd under identical management conditions. Milk yield and blood biochemical parameters were examined during the periparturient period in Holstein (H) and Fleckvieh (F) cows. Blood samples were first taken on average 14 days prior to the expected date of calving, next in the peripartal period (1–4 days postpartum), and then at weekly intervals (together with milk samples) until the end of the experiment (8 weeks postpartum). Milk yields were higher in H cows from the second week after calving whereas milk protein content always was higher in F cows over the whole experimental period. The level of metabolic stress determined using blood concentrations of nonesterified fatty acids (NEFA), β-hydroxybutyrate (BHB), triglycerides, and cholesterol was similar in both breeds. The proportion of animals with concentrations of NEFA and BHB above thresholds indicating increased risk of negative energy balance and subclinical ketosis was higher in the H breed in the first 2 weeks after calving. This corresponds with numerically higher concentrations of NEFA and BHB in H cows. Changes in the protein status of animals generally reflected the development in energy metabolism parameters. Serum total protein, albumin,and urea levels were similar in the two breeds. Total globulin was higher in H cows than in F cows in weeks 3, 4, and 5 after calving, and the albumin-to-globulin ratio was lower in H cows than in F cows in weeks 2, 3, and 4 after calving. In conclusion, although the onset of changes in key metabolic parameters was rather faster and more pronounced in the H breed, similar dynamics in the development of these parameters indicated similar levels of adaptive performance and body energy mobilization processes in the two breeds.