The objective of this meta-analysis was to evaluate the effects of weight loss or weight gain of beef cows during the second and/or third trimester of gestation on the postnatal performance of the progeny. The variation in cow weight during the gestational period was calculated to standardize the treatments, being them: severe loss (SL = cows that lost more than 10% of weight); moderate loss (ML = cows that lost from 0 to 10% of weight) and weight gain (WG = cows that gained weight). The intensity of the cow weight variation effect was calculated as the mean difference (MD) with a 95% confidence interval and heterogeneity determined using the Q test and the I2 statistic. A meta-analysis of random effects was conducted for each indicator separately with the means of the control and experimental groups. Calves from WG cows were higher for birth weight (P = 0.0094); weight adjusted to 205 days (P = 0.0127) and average daily gain during pre-weaning (P < 0.0001) in relation to calves from ML cows. The W205 of calves from SL cows was 11.6 kg lower than the progeny from ML cows. The post-weaning performance of the progeny tended (P = 0.0868) to be higher in the progeny of WG cows than ML ones. The weight gain of beef cows during gestation improves the pre- and post-weaning performance of the progeny, with more evident effects in the early months of life of the offspring.

The objective of this study was to evaluate the metabolic status of beef cows during the final third of gestation and thereafter until the end of the subsequent breeding season. The study was conducted using 30 beef cows, aged between 4 and 11 years, derived from crosses between Charolais and Nellore cattle. To assess the metabolic status of cows, we obtained measurements of body weight and condition (BW and BCS), and complemented these by analyzing the following blood metabolites: total proteins, globulins, albumin, glucose, cholesterol, and triglycerides. Assessments were performed at 95 days pre-calving, and again at 7, 21, 63, and 110 days post-calving. The experimental design was completely randomized with five collection periods and 30 repetitions (cows). The BW of cows was found to be highest at 110 days postpartum (489.1 kg), and loss of BW was observed between 21 and 63 days postpartum (-3.72 kg). The lowest BCS value was recorded after 63 days of lactation (2.85 points). With respect to blood metabolites, concentrations of total proteins were higher at 7 and 110 days postpartum relative to the levels recorded during gestation (8.3 and 8.3 vs. 7.7 g dL-1, respectively), whereas serum globulin levels were higher at 7, 21, and 110 days postpartum relative to those at gestation (5.2, 5.2, and 5.1 vs. 4.8 g dL -1, respectively). Compared with samples obtained during gestation, the highest levels of albumin (P < 0.05) were observed at 7, 63, and 110 days postpartum (3.1, 3.1, and 3.2 vs. 2.9 g dL-1, respectively). Serum glucose was higher during pregnancy and in the first week of lactation relative to the values recorded after 21 and 63 days of lactation (80.9 and 76.7 vs 71.5 and 72.3 mg dL-1, respectively). Moreover, cholesterol concentrations increased with the progression of lactation, with the highest value being recorded at 110 days postpartum (222.1 mg dL-1). Collectively, the findings of this study, indicate that Charolais × Nellore cows raised exclusively on native pasture mobilize body reserves, lose weight, and show a negative energy balance during the first weeks of lactation, with detrimental consequences for subsequent reproductive activity.

The present study was developed at the Beef Cattle Laboratory of the Federal University of Santa Maria and evaluated the effect of three levels of concentrate supplementation (S 0.8, S 1.0, and S 1.2, corresponding to 0.8%, 1.0%, and 1.2% of bodyweight, respectively) on the ingestive behavior and movement patterns of 24 steers grazing on sorghum. The experiments were performed using a completely randomized block design in a 3 ? 3 factorial arrangement (three levels of supplementation ?three experimental periods), and the grazing time was evaluated using a 3 ? 24 factorial arrangement (three levels of supplementation ? 24 hours of observation). The steers fed S 0.8 presented longer(P=0.009) grazing time in the morning (241 min day-1) compared to animals fed S 1.2(172 min day-1). The number of bites per feeding station was higher (4.05) during the second experimental period, and the number of bites min-1 increased from 25.4 to 31.4 from the first to the second experimental period. The changes in sward structure during the growth stages of sorghum affected the number of bites per feeding station and the number of bites per minute.

The objective of the meta-analysis was to evaluate the effects of beef cows weight variation during the 2nd and / or 3rd trimester pregnancy on some parameters of the progeny carcass. The cow weight gain during this gestational period was calculated to standardize the treatments: moderate loss (ML= cows that lost 0 to 5 % of weight) and moderate gain (MG= cows that gained 0 to 5 % of weight). The effect size for all parameters was calculated as medium difference (MD) with a 95% confidence interval and heterogeneity determined using the Q test and the I2 statistic. A random effects meta-analysis was performed for each indicator separately as the medium control and experimental groups. The cow’s weight variation during the studied time variation did not influence the progeny carcass characteristics (P>0.05). Although, a trend towards greater hot carcass weight (P=0.15) and thickness of subcutaneous fat (P=0.10) was observed in calves from MG cows in relation to calves from ML cows. However, the meta-analysis demonstrated that small variations in cow weight during the final half of pregnancy do not affect progeny carcass characteristics.

The restriction of nutrient intake by beef cows during pregnancy may influence the progeny postpartum growth potential, therefore, the objective of the present study was to evaluate the effects of nutritional restriction and adequate nutrition or overfeeding during the final third of gestation of the crossbred cows (Charolais x Nellore) kept in the Pampa biome, on the productive performance of the progeny up to 15 mo of age. Eighty-three (83) cows were divided into: control cows on natural pasture under nutritional restriction (RES); Supplementation to meet 100 % of requirements (REQ); Supplementation above requirements (HIGH). REQ and HIGH calves had higher body weight at birth compared to calves from RES cows (39.28, 39.13 vs 34.58 kg), without influences on postnatal performance. Females from REQ and HIGH cows presented better postnatal performance and consequently higher weight at 12 mo of age in compared to offspring RES cows (300.71 and 311.79 vs 259.47 kg). These female calves reached 60 % of early adult weight (358 and 345 vs 405 d) and had a higher percentage of breeding at twelve months of age (73.98 and 84.08 vs 34.08 %) than females from RES cows. Supplementing cows to meet 100% requirements, as well as overfeeding during the final third of gestation, improves offspring performance at twelve months of age, with males and females responding differently to maternal nutritional insults during this period.