Relationships between conformation traits and functional longevity in Holstein cows were evaluated using survival analysis. Functional longevity was defined as the number of days between the first calving and culling; that is, length of productive life. The data set consisted of 116,369 Holstein cows that first calved from 2003 to 2008. All cows used in the analysis were scored for conformation between d 30 and d 210 of their first lactation. The data included 48% censored records. Analyses were done separately for 20 linear descriptive type traits, 6 composite traits, and height at sacrum measured in centimeters. Cox proportional hazard models were fitted to analyze data. The hazard function was described as the product of a baseline hazard function and the time-independent effects of age at first calving and sire (random), and the time-dependent effects of stage of lactation and lactation number, herd, year and season, herd size, and 305-d milk production. The strongest relationship between a composite trait and functional longevity was for dairy form, followed by udder and final score. Among the descriptive type traits, the strongest relationships with longevity were found for body condition score, angularity, traits related to udder attachment, and udder depth. Foot and leg traits showed substantially lower effect on functional longevity, and the effect of foot angle was minimal. Functional longevity declined with decreased body condition score of cows. Cows with deep udders had significantly lower functional survival compared with cows with shallow udders. In addition, weak central ligament was associated with significant reduction of cow longevity. For dairy form and angularity, cows classified as very good were the worst with respect to longevity, whereas cows classified as poor were the best. An intermediate optimum was evident for rear legs rear view and rear legs set (side view), whereas cows with sickled legs had lower longevity than cows with straighter legs.

Genotypes of milk protein genes, alpha S1 -casein (CSN1S1), beta-casein (CSN2), kappa-casein (CSN3) and beta-lactoglobulin (LGB), were detected in 440 individuals of Czech Fleckvieh breed using a PCR-RFLP method. Breeding values of genotyped animals were obtained from the Official Database of Progeny Testing. A granddaughter design including 5 grandsires, 33 sons and 402 granddaughters was used for evaluation. Statistical analysis was carried out in SAS program using a restricted maximum likelihood method (REML). The aim of this study was to determine allele and genotype frequencies of observed genes and to find the relation between genotypes of genes and milk production parameters expressed by the breeding values of animals. The positive findings of frequencies of CSN3 allele B (0.38) and genotype BB (13%) were detected in the observed population. Significant differences were found between genotypes of loci CSN1S1, CSN2 and CSN3 and breeding values for milk production parameters. Genotypes of LGB locus were not significantly related to any of the milk production parameters. Significant effects were found between CSN1S1 locus and average breeding value for milk yield, CSN2 locus and breeding values for all parameters except for protein content and CSN3 locus and breeding values for protein content and protein yield. These findings contribute to a better understanding of the genetic constitution of Czech Fleckvieh breed and help with the application of the information to breeding.

ABSTRACT:The aim of this study was to estimate genetic parameters for female fertility and production traits in first-parity Czech Holstein cows and to quantify the effect of using this information on the accuracy of a selection index in seven different scenarios. In order to estimate genetic (co)variance components, the DMU software running an AI-REML algorithm was used. The analyses were made using a series of bivariate animal models. The pedigree included 164 125 animals and it was set up using a pruned animal model design. The present study included the following female fertility traits for the first lactations: calving to the first insemination (CF), days open (DO), calving from the first to the last insemination (FL), and milk production traits: milk production (MLK), kg of fat (FAT), and kg of protein (PROT). The heritability for all the investigated fertility traits was low and close to 0. Moderate heritabilities for production traits ranging from 0.20 (MLK) to 0.23 (PROT) were estimated. The strongest unfavourable correlation was found between PROT and DO (0.49). Other estimated correlations between fertility traits and production traits were moderate, ranging from 0.26 to 0.41. The results of this study evidence that cows with the poorest genetic potential for reproductive performance are those having high genetic potential for milk production and milk components. The results also show that the number of days from calving to new pregnancy depends on the production level. Seven investigated scenarios using selection index theory show a clear trend for increasing accuracy when more fertility traits were added as well as when higher numbers of daughters with information on reproduction traits per sire were available.

Genetic correlations between longevity and conformation traits were estimated using data on Czech Holstein cows first calved in the years 1993–2008. Longevity traits considered were length of productive life and number of lactations initiated and their functional equivalents (i.e. the longevity traits corrected for milk production). Conformation traits were twenty one linear descriptive type traits, six composite traits and height at sacrum measured in cm. A possible nonlinear relationship between conformation and longevity traits was also investigated. The heritabilities ranged from 0.05 to 0.43 for conformation traits and from 0.03 to 0.05 for longevity traits. Low to moderate genetic relationships between conformation and longevity traits were found. The genetic correlations were higher for functional longevity than for direct longevity traits. Negative genetic correlations with all longevity traits were found for height at the sacrum, stature, dairy form, body conformation, and capacity. Final score showed weak genetic correlation with all analyzed longevity traits. Positive genetic correlations occurred between feet and legs and direct longevity and functional longevity (0.19, 0.14) and between udder and direct longevity (0.10). Body condition score and angularity showed strong genetic correlations with functional longevity (body condition score 0.30, angularity –0.31). Foot and leg traits showed weak genetic correlations with longevity traits except rear legs set (side view) (–0.24) and hock quality (0.19). The udder traits showed inconsistent and rather weak genetic correlations with longevity traits, with the exception of a stronger genetic correlation between rear udder width and functional longevity (–0.22) and between central ligament and number of lactations (–0.18, –0.19). The teat traits showed always negative genetic correlations with longevity traits. The strongest correlations were found for rear teat position (–0.28) and the weakest for teat length (–0.03). Some conformation traits showed markedly stronger genetic correlations with functional longevity than with direct longevity (rear udder width and rear udder height, dairy form, body condition score, angularity, rear legs set (side view), rear legs rear view). A quadratic relationship between conformation and longevity traits did exist. Even if the linear relationship generally prevailed, the quadratic relationship should be taken into account.  

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.