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Showing 1 to 19 of 19 for “"calving interval"”.
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Relationships between first lactation milk yield, first calving interval, herd life, lifetime milk production, and descriptive type subtraits in Holstein cattle
… related to first lactation production, first calving interval, herd life, and lifetime milk and fat yields. Variables other than type traits were expressed as deviations from the contemporary average. Heritabilities of type subtraits ranged from .00 to .45. First lactation milk and fat yields …
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Comparisons of Holstein, Brown Swiss, and Jersey cows for age at first calving, first calving interval, and true herd-life up to five years in seven regions of the United States
… for heat-stress resistance using age at first calving and first calving interval, and to assess breed by region interactions for seven regions of the United States for survival-related traits up to five years of age in Brown Swiss, Holstein, and Jersey cows. Age at first calving and first …
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Heritability estimates for calving date in Simmental cattle
… Traits analyzed included first and second calving dates, first calving interval and the percentage of cows that returned to calve in the same season as 3-yr-olds. Data were adjusted for effects of percentage Simmental and first-calf calving ease score. At second calving, purebred Simmentals …
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Factors Influencing the Reproductive Efficiency of Dairy Herds in the Dominican Republic
… first service, services per pregnancy, projected calving interval, and service rate. In general, reproductive management practices varied depending on region and farm size. Average lameness within the herd was the most important factor in explaining the variability within services per pregnancy …
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Genetic Parameters and Genetic Trends of Female Fertility in Icelandic Dairy Cattle
Fertility, represented by calving interval, has been included in the genetic evaluation of Icelandic dairy cattle since 1993. In spite of this an unfavourable genetic trend is seen and, recent implementation of test-day models for the genetic evaluation of milk production has changed the premise of …
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Efeito do cromossomo x no mapeamento de regiões genômicas sobre características de interesse econômico em búfalos da raça murrah
… related to reproductive traits (age at first calving – AFC, first calving interval – CFI1, and second calving interval – CFI2) in Murrah buffaloes. CFI1 represents the period from an animal's calving to the subsequent one during its first lactation, while CFI2 refers to the interval between …
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Genotype by environment interaction for Holstein milk yield and fitness traits between Saudi Arabia and the United States
… was identified separately for first and multiple calving cows. Estimates of genetic correlations for milk yield between the two regions in first and all lactations were .68 and .17, respectively. In first lactation analysis, additive genetic variances were similar but residual variance was 21% …
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Grouping and feeding policies for lactating dairy cows
… squares. Days in milk, available nutrients, calving date, and previous period 4% FCM accounted for 90% of the variation in 4% FCM for heifers and 93% of the variation in 4% FCM for cows with previous lactations. Days in milk, acid detergent fiber, calving date, and dry matter intake from the …
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Development of an expert system for the evaluation of reproductive performance and management of Virginia dairy farms
… interpretations correspond to a 12 to 13 mo calving interval. The system then selects for evaluation one of three areas that influences days open; days to first insemination, efficiency of detection of estrus, or conception percentage. Once an area has been selected for further evaluation, …
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Birth, death and taxis: North Atlantic right whales in the twenty-first century
… in North Atlantic right whales is in a decline. Calving intervals have increased from about 3.3 years in the 1980's to over 5 years, and the age of first parturition is estimated to be 11 years. Females may lose calves before they are detected, artificially increasing the apparent age of first …
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Effect of Days Open on Lactation Production
… account the geographical location, season of calving, breed, age at calving, and milking frequency for both milk and fat, independently of one another. These factors are regarded as being adequate in removing variation arising between herdmates. Reproductive efficiency is of economic …
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Postpartum ovarian activity and response to progestagen treatment in rustic beef cows (Spanish Retinta) underfed to simulate their typical ranging conditions
… pasture scarcity but exhibit a prolonged calving interval. This study characterized the ovarian activity and response to progestagen treatment (Synchromate-B type) in feed-restricted, postpartum Retinta cows. Forty cows were fed a restricted diet so that competition among cows resulted in …
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Genetic and phenotypic relationships among fifteen measures of reproduction in dairy cattle
… period length, days open, age at first breeding, calving interval, days between services, and return to estrus lag. First, second and third service period were each analyzed separately, while fourth and later service periods were pooled. Heritability was estimated using the sire component of …
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Evaluating long term benefits of genomic selection programs in beef cattle breeding programs in Western Canada
… repeated) were followed over 6 breeding and calving years to determine the association between sire performance over multiple years, number of calves sired, calf performance, and replacement heifer performance over multiple years. To evaluate sire performance and account for the different …
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Predator movements in complex geography: Spatial distribution and temporal occurrence of low-density bottlenose dolphin communities off western Scotland
… population’s demographic parameters (birth rate, calving interval and calf survival) were comparable to those reported for the species globally.<br/>This study showed that the integration of complementary methodological approaches is useful in investigating mobility patterns of low-density …
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Holstein heifer behaviors and lactating cow nutritional management for improved reproductive performance on dairy farms
… late lactation, higher feed costs from a longer calving interval, and more labor and supplies from multiple breedings. To investigate techniques to improve the reproductive efficiency on dairy farms, two experiments were conducted involving Holstein heifers of breeding age and early postpartum …
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Monitoring and improving reproductive performance of crossbred dairy cattle in Tigray Region, Ethiopia
… late, and cows have long postpartum estrus and calving interval. Anestrus, repeat-breeding, dystocia, retained fetal membranes (RFM), endometritis and abortion as the major reproductive problems in dairy cattle in the study area. Serum, milk, saliva and urine P4 and serum estradiol profiles of …
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Nutritional and genetic characterization of dairy cows managed on pasture-based systems, identifying key aspects to improve their performance
… and milk fat, as well as somatic cell score and calving interval records were provided by the Chilean cooperative COOPRINSEM. The proportion of each breed according to the different country origin (strain) was calculated for all the animals, being identified eight genetic strains with enough …