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The objective of this study was to analyze the influence of genetic group (GG) of the calf during gestation, mobilization of body reserves and period of postpartum anestrus in Nellore cows. Thirty-seven primiparous and multiparous cows were used: 24 gave birth to Nellore (NEL), and 13 gave birth to ½ Simmental × ½ Nellore (SIM) calves. According to...
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The backfat thickness (BFT) was used to forecast the onset of ovarian activity and predict the calf growth. Eighty Brahman cows with their calves were allocated in two groups of 40 distributed in 4 months according to the month of calving, starting in March and finishing in June. One was synchronized and inseminated at fixed time following by natur...
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... Although there are nutritional and management strategies for the primary prevention of NEB, but the negative economic impact of NEB in dairy cattle is undeniable (Loor, 2010). However, it is merit to mentioning that the negative economic and welfare impact of NEB on a bovine depends on its intensity and duration (Vargas Junior et al., 2013). Hence, it is possible to have cows with certain degree of NEB and different health and reproductive performance. ...
Negative energy balance (NEB) is an altered metabolic state in modern high-yielding dairy cows. This metabolic state occurs in the early postpartum period when energy demands for milk production and maintenance exceed that of energy intake. Negative energy balance or poor adaptation to this metabolic state has important effects on the liver and can lead to metabolic disorders and reduced fertility. The roles of regulatory factors, including transcription factors (TFs) and micro RNAs (miRNAs) have often been separately studied for evaluating of NEB. However, adaptive response to NEB is controlled by complex gene networks and still not fully understood. In this study, we aimed to discover the integrated gene regulatory networks involved in NEB development in liver tissue. We downloaded data sets including mRNA and miRNA expression profiles related to three and four cows with severe and moderate NEB, respectively. Our method integrated two independent types of information: module inference network by TFs, miRNAs and mRNA expression profiles (RNA-seq data) and computational target predictions. In total, 176 modules were predicted by using gene expression data and 64 miRNAs and 63 TFs were assigned to these modules. By using our integrated computational approach, we identified 13 TF-module and 19 miRNA-module interactions. Most of these modules were associated with liver metabolic processes as well as immune and stress responses, which might play crucial roles in NEB development. Literature survey results also showed that several regulators and gene targets have already been characterized as important factors in liver metabolic processes. These results provided novel insights into regulatory mechanisms at the TF and miRNA levels during NEB. In addition, the method described in this study seems to be applicable to construct integrated regulatory networks for different diseases or disorders.
... El desempeño reproductivo de bovinos para carne en el trópico es afectado por factores ambientales, generalmente asociados con la condición corporal al parto y su dinámica durante el periodo posparto (1) . El intervalo entre el parto y el reinicio de la actividad ovárica puede ser un obstáculo importante para la mejora de la eficiencia reproductiva, ya que es el principal responsable del aumento del intervalo entre partos (2) , que es influenciado por la raza, nutrición, producción de leche, presencia del becerro, estación del año, presencia del semental (3) y el número de parto (4) . ...
... Dado que los Reproductive performance of beef cattle in the tropics is affected by environmental factors usually associated with body condition at calving and their dynamics during the postpartum period (1) . The interval between calving and the resumption of ovarian activity can be a major obstacle to the improvement of the reproductive efficiency, as it is responsible for the calving interval (2) , which is influenced by breed, nutrition, milk production, presence of the calf, season of the year, presence of the sire (3) and number of calving (4) . ...
... El desempeño reproductivo de bovinos para carne en el trópico es afectado por factores ambientales, generalmente asociados con la condición corporal al parto y su dinámica durante el periodo posparto (1) . El intervalo entre el parto y el reinicio de la actividad ovárica puede ser un obstáculo importante para la mejora de la eficiencia reproductiva, ya que es el principal responsable del aumento del intervalo entre partos (2) , que es influenciado por la raza, nutrición, producción de leche, presencia del becerro, estación del año, presencia del semental (3) y el número de parto (4) . ...
... Dado que los Reproductive performance of beef cattle in the tropics is affected by environmental factors usually associated with body condition at calving and their dynamics during the postpartum period (1) . The interval between calving and the resumption of ovarian activity can be a major obstacle to the improvement of the reproductive efficiency, as it is responsible for the calving interval (2) , which is influenced by breed, nutrition, milk production, presence of the calf, season of the year, presence of the sire (3) and number of calving (4) . ...
The aim of the study was to analyze the impact of environmental factors as well as to estimate components of (co) variance of reproductive traits in Chacuba cattle. For that, 4,957 records of cows, daughters of 893 dams and 110 sires were used. Models that considered number of parity, calf sex, and contemporary group (herd-year-season of calving) as fixed effects were tested. The season of calving was included as every two, three, four and six months. The interval from calving to conception (ICC), calving interval (CI), and services per conception (SC) were the traits analyzed with uni and multitrait models using the software ASReml. The parity (P<0.01) and the contemporary groups (P<0.01) significantly affected the reproductive traits; however, the calf sex (P>0.05) was not. The heritability for the traits analyzed were low with values of 0.14±0.02, 0.15±0.02 and 0.04±0.01 for ICC, CI and SC, respectively. Genetic correlations were high between ICC and CI (0.99±0.43) but low between ICC and SC (0.10±0.14) and between CI and SC (0.09±0.11). Genetics parameters estimation models for the traits ICC, CI, and SC for Chacuba cows should consider parity and herd-year-quarter contemporary groups. Indirect selection for the calving interval using the interval calving-conception, can be implemented given the genetic correlation between these traits.
... The results of the P205 analysis were similar to those of Barbosa and Alencar (1995) and Cubas et al. (2001), who reported a 10-12% higher average weight at weaning for cross-bred calves than for pure-bred Nellore calves. Vargas et al. (2013), in contrast, compared ½Simmental-½Nellore calves with pure-bred Nellore calves and found only a 6% difference in favour of the cross-bred calves. ...
... The GP that we recorded was in accordance with that reported by Gunsky et al. (2001), who found that the average Nellore pregnancy period (PP) in Brazil is 295 days. Vargas et al. (2013) observed that the GP of Nellore mothers of pure-bred calves was 8 days longer than that of mothers of cross-bred calves, whereas Koger (1980) andBrowning et al. (1996) observed shorter PPs for mothers of cross-bred calves. Baruselli et al. (2007) noted that the pregnancy of Bos taurus indicus is on average 10 days longer than that of B. taurus (292 vs 282 days, respectively). ...
... However, because the breed of the calf had no effect on the mother's BCS and because there was no interaction between the genetic group and the time of BCS measurement, the genetic group of the calf did not seem to influence the energy balance of the mother. Vargas et al. (2013) reported that the milk consumption of cross-bred calves birthed by Nellore mothers was 0.42 kg/head/day higher than that of pure-bred Nellore calves (8.6%), but a body condition analysis of the mother cows suggested that the genetic group of the calf had an effect on the mother's health or performance. The higher WW of the cross-bred calves therefore appears to be mainly due to an extended grazing period (Rodrigues 2009). ...
The objective of the present research was to evaluate the effect of a calf's genetic group on the productive and reproductive efficiency of its Nellore dam. Fixed-time artificial insemination was applied to 800 cows using semen extracted from Nellore, Simmental and Angus Red bulls. Four hundred eleven cows calved, producing 119 Nellore, 103 ½Simmental-½Nellore and 189 ½Nellore-½Angus Red calves. The second mating period, which paired Nellore cows with Simmental bulls, was initiated 10 days after parturitions began and lasted for 5 months. Based on the two successive parturitions, the cumulative parturition rate for calving periods of 3, 4 and 5 months was calculated. Although no significant difference was observed for birth weight among the genetic groups, cross-bred calves weighed, on average, 10% more than did pure-bred calves at the age of 205 days. Nellore dams experienced a gestation period that was 7 days longer than did the cross-bred dams, and the former showed a higher parturition rate at 90 and 120 days of the calving season, but not at 150 days (calving rates of 80.6, 76.4 and 76.2% for mothers of Nellore, ½Nellore-½Angus Red and ½Nellore-½Simmental, respectively, p > 0.05). At 90 and 120 days, Nellore dams produced more kg of calf per mated dam. In conclusion, in a short breeding season, Nellore dams nursing pure-bred Nellore calves were found to have a higher biological efficiency compared with Nellore dams nursing cross-bred calves.
© 2015 Blackwell Verlag GmbH.
The aim of the study was to analyze the impact of environmental factors as well as to estimate components of (co) variance of reproductive traits in Chacuba cattle. For that, 4,957 records of cows, daughters of 893 dams and 110 sires were used. Models that considered number of parity, calf sex, and contemporary group (herd-year-season of calving) as fixed effects were tested. The season of calving was included as every two, three, four and six months. The interval from calving to conception (ICC), calving interval (CI), and services per conception (SC) were the traits analyzed with uni and multitrait models using the software ASReml. The parity (P<0.01) and the contemporary groups (P<0.01) significantly affected the reproductive traits; however, the calf sex (P>0.05) was not. The heritability for the traits analyzed were low with values of 0.14±0.02, 0.15±0.02 and 0.04±0.01 for ICC, CI and SC, respectively. Genetic correlations were high between ICC and CI (0.99±0.43) but low between ICC and SC (0.10±0.14) and between CI and SC (0.09±0.11). Genetics parameters estimation models for the traits ICC, CI, and SC for Chacuba cows should consider parity and herd-year-quarter contemporary groups. Indirect selection for the calving interval using the interval calving-conception, can be implemented given the genetic correlation between these traits.
The objective of this work was to evaluate the weight and reproductive performance of beef cows subjected to different nursing managements. During the breeding season of 85 days, 161 beef cows of the Purunã breed were evaluated, according to the following feeding managements: early weaning, cows separated from their calves at 75 days postpartum; controlled nursing, cows separated from their calves at 75 days of age, but taken to nurse once a day during the breeding season; and conventional weaning, cows kept with their calves until the end of the breeding season, at 160 days of age of calves, in average. Fertility rates were not significantly affected by weaning managements, being 97% for early weaning, 96% for controlled nursing, and 90% for conventional weaning. However, early weaning resulted in lower reproductive efficiency (28.26 kg), when compared to controlled nursing (35.09 kg) and conventional weaning (35.34 kg). Beef cows maintained in good body conditions at birth and at the beginning of the breeding season have a high fertility rate, regardless of calf-feeding management.
