Analysis of factors affecting the length of productive life in Croatian dairy cows (original) (raw)
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The impact of age at the first calving on lifetime milk yield, life span and herd life of dairy cows
Annals of Warsaw University of Life Sciences - SGGW - Animal Science, 2019
The impact of age at the fi rst calving on lifetime milk yield, life span and herd life in dairy cows. The increasing importance of functional traits (e.g. longevity) in cattle breeding is the result of their direct effect on profi tability of production. The main objective of the study was to determine the infl uence of age of the fi rst calving on lifetime milk yield, life span and herd life in Polish dairy cows. Cows were kept on farms with milk performance recording system. One-way analysis of variance was used to calculate the impact of age of the fi rst calving on selected traits. Cows that fi rst calving occurred at the age of 791-850 day achieved the highest lifetime milk, fat and protein yield per one day of life (P ≤ 0.01). Moreover, their life span was also the longest (P ≤ 0.01) and milk and protein yield per 1 day of utilization were the highest (P ≤ 0.01). Obtained results suggest that the most favorable time of calving for dairy heifers is between 791-850 day of life. Therefore, milk producers should carefully consider the most suitable time of heifers insemination in order to achieve the most satisfying milk production.
animal, 2013
In most studies on beef cattle longevity, only the cows reaching a given number of calvings by a specific age are considered in the analyses. With the aim of evaluating all cows with productive life in herds, taking into consideration the different forms of management on each farm, it was proposed to measure cow longevity from age at last calving (ALC), that is, the most recent calving registered in the files. The objective was to characterize this trait in order to study the longevity of Nellore cattle, using the Kaplan-Meier estimators and the Cox model. The covariables and class effects considered in the models were age at first calving (AFC), year and season of birth of the cow and farm. The variable studied (ALC) was classified as presenting complete information (uncensored 5 1) or incomplete information (censored 5 0), using the criterion of the difference between the date of each cow's last calving and the date of the latest calving at each farm. If this difference was .36 months, the cow was considered to have failed. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The records of 11 791 animals from 22 farms within the Nellore Breed Genetic Improvement Program ('Nellore Brazil') were used. In the estimation process using the Kaplan-Meier model, the variable of AFC was classified into three age groups. In individual analyses, the logrank test and the Wilcoxon test in the Kaplan-Meier model showed that all covariables and class effects had significant effects (P , 0.05) on ALC. In the analysis considering all covariables and class effects, using the Wald test in the Cox model, only the season of birth of the cow was not significant for ALC (P . 0.05). This analysis indicated that each month added to AFC diminished the risk of the cow's failure in the herd by 2%. Nonetheless, this does not imply that animals with younger AFC had less profitability. Cows with greater numbers of calvings were more precocious than those with fewer calvings.
Indian Journal of Animal Research, 2019
The effect of age at first calving (AFC) and various non-genetic factors i.e. season of calving, farm and system of housing on longevity and production traits were investigated. Longevity traits were studied using total lifetime (TL), length of productive life (LPL) and number of lactations (NL) while production was researched using lifetime milk yield (LMY). Data of 2037 Holstein dairy cows were provided by the main breeding organizations at the Faculty of Agriculture, University of Novi Sad. The average values and variability of examined traits as well as the effect of factors on longevity and production traits were investigated using fixed effect model by general linear model (GLM) procedure in software package Statistica 13. Results showed highly significant effect of the AFC, calving season and farm, on all studied longevity traits (P less than 0.01), while non- significant effect was expressed on lifetime milk yield (P greater than 0.05). The mean of AFC, TL, LPL, NL and LMY f...
Longevity of high-yielding cows
Population of Black and White cattle has high genetic potential for production of milk. It exists in very complex production conditions where problems occur which are often manifested in different health disorders, high percentage of culling and short productive life. Longevity parameters are calculated within defined time limits. Bottom limit is determined by date of birth, and top limit by date of culling. The knowledge of the strength of the influence of environment on the longevity of high yielding cows is important from the aspect of its inclusion into the model. According to individual significance of systematic factors, their objective assessment was carried out in order to evaluate the obtained results as precise and correct as possible. Previous studies of the average age of cows at culling from the herd indicated relatively short productive life and life in general of high yielding cows, which due to high percentage of culling effects the herd remount. Consequently selection differential is reduced and in this way realized selection effect is diminished. Objective of this paper was to investigate using appropriate methodology the longevity of high yielding Black and White cows of different genotypes through major systematic influences. Investigated cows according to their origin belong to European type of Black and White cattle in final stage of intensive improvement using Holstein-Friesian breed. Investigated sample included 331 cows. Average age of cows at culling is 2265±463.26 days or 6.21±1.27 years. Observed by cow genotypes, mean values varied from 2140.99 days (> 73% HF), 2247.51 days (58-73% HF) to 2406.97 days (<58% HF). Average lifetime production was realized at the level of 25002.66±7755.39 kg of milk with 3.61±0.01% of milk fat.Bulls, sires of cows, class of HF genes and year of culling had highly significant effect (p≤0.01), whereas the effect of reason for culling was significant (p≤0.05) for life duration of cows.
Revista Mexicana de Ciencias Pecuarias
The aim was to determine the effect of age at first calving on longevity, lifetime number of productive days and lifetime milk yield of Holstein and Brown Swiss cows in the tropical savanna of Honduras. The information was collected from three dairy farms with Holstein (n = 1,391) and four farms with Brown Swiss cows (n = 480), born from 1993 to 2013, managed under intensive systems. The statistical model that described the variables of interest included the effect of farm, group of age at first calving, period of birth, season of birth and the interaction farm x period and the residual error. Effects of farm, period group of age at first calving and interaction of farm x period were found on the response variables. A favorable effect of the cows that had their first calving at an earlier age on lifetime number of days in production and lifetime milk yield, and an increase in longevity, in both Holstein and Brown Swiss cows (P<0.05). In conclusion, cows that calved at an early a...
The age at first calving and the longevity of beef cows in Hungary
Archives Animal Breeding, 2006
The length of time beef cows spend in production is an important component of the rentability of beef cattle husbandry. In spite of this fact, very few publications have dealt with this trait, either in Hungary or abroad. Therefore the aim of the present study was to evaluate some of the age parameters of beef cows related to the production period. A database of 2115 cows belonging to five breeds (Hungarian Grey, Hereford, Aberdeen Angus, Limousin, Charolais) and two crossbred genotypes (Simmental x Hereford F 1 , Simmental x Limousin F 1) born between 1977-1992 was evaluated. Age at first calving (AFC), age at culling (ACU), moreover longevity (LONG) were studied. Longevity is defined as the number of years from first calving to culling. The mean values of AFC, ACU and LONG obtained were 2.71, 9.47 and 6.77 years, respectively. Breed/genotype and birth year had significant influence (P<0.01) on each evaluated trait, whereas birth month statistically affected only the AFC. Ages at first calving of the different breeds and genotypes were: 3.51, 2.08, 2.76, 2.82, 3.02, 2.03, 2.62 years, respectively. Hereford crossbred and purebred cows were the youngest, whereas Hungarian Grey cows were the oldest at first calving. Ages of culling of the evaluated breeds and genotypes were as follows: 12.42,
Relationship Between Age at First Calving and Longevity and Productive Life in Holstein Cows
Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, 2020
The aim of the study was to evaluate the effect of age at first calving on functional traits-longevity and productive life in dairy cows. The survey included 1490 Holstein cows from 5 cattle farms in Bulgaria. The average milk yield per cow in the farms studied ranged from 6031.68 kg to 8660.37 kg. The average age at first calving was 29.68 months. The highest percentage of cows calved for the first time at age 28-30 months-29.53%, generally 38.06% of cows calved for the first time at a very high age-over 31 months and only 7.58% calved aged up to 24 months. The average longevity for all culled cows was 6.05 years and the productive life-3.63 years. 22% of all culled cows at these farms were culled before the end of their first lactation. The highest total longevity was in cows calved for the first time at high age-over 28 months. Cows calved for the first time, both at low age (up to 24 months) and at high age (over 37 months), had a shorter productive life of 4.0 and 3.9 years, respectively. Cows with the shortest productive life-one year and less-had and the highest average age at first calving of 30.21 months.
Livestock Science, 2010
Records of functional longevity (FL), from first calving to last recording (or culling), of 36,888 Tunisian Holstein cows in 169 herds were studied using survival analysis. Using a Weibull proportional hazard model, the influences of age at first calving, herd–year–season, lactation number–stage of lactation, milk production within the herd and year, annual change in herd size and random genetic effect of sire on FL were studied. Besides a random time-dependent effect of herd–year–season, the model included fixed effects of parity and stage of lactation, within herd and parity production level (all time-dependent), and age at first calving (time-independent). All factors had a significant effect on FL at a level of P < 0.001. Milk yield was by far the most important factor influencing FL and the hazard increased as the milk production decreased. Within the first three lactations, the relative culling risk increased stepwise with lactation stage. The highest risk of culling was found for cows at the beginning and at the end of the first lactation and at the end of any other lactation. The risk of culling decreased with parity.
Animals
Longevity is one of the functional traits that considerably affect dairy herd profitability. A Weibull proportional hazards model was used to evaluate the impact of difficult calvings and calf stillbirths on cow functional longevity, defined as length of productive life corrected for milk production. The data for analysis comprised calving ease and calf mortality scores of 2,163,426 calvings, 34.4% of which came from primiparous cows. The percentage of male calves was 53.4%. Calving ease was scored as “without assistance” (34.44%), “with assistance” (62.03%), “difficult—hard pull” (3.39%), and “very difficult, including caesarean section” (0.14%). Calf mortality scores were “live born” (94.21%) and “stillborn or died within 24 h” (5.79%). The Weibull proportional hazards model included classes of calving ease or calf mortality scores × parity (1, ≥2) × sex of calf as time-dependent fixed effect. The model also included time-dependent fixed effects of year × season, parity × stage of...
Relationship between longevity and selected production, reproduction and type traits
Czech Journal of Animal Science
The correlations between longevity, functional longevity, stayability and selected milk, reproductive and type traits were estimated; it was done on the basis of estimated breeding values for longevity, functional longevity, dairy traits, reproductive traits and stayability rates at the age of 60, 72, 84, and 96 months. The correlation between breeding values for longevity and functional longevity was 0.69. The correlations between longevity and stayability at 60, 72, 84, and 96 months of age were around 0.75 (from 0.73 to 0.76) whereas the correlation with stayability at 48 months was considerably lower (0.64). The breeding values for dairy traits showed a positive relationship with longevity (from 0.37 to 0.46) and a slightly negative correlation with breeding values for functional longevity (from –0.10 to –0.20). A low relationship was found between longevity and reproductive traits. Between the type traits and longevity traits only the conformation score for the form...