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This study aimed to determine protein and energy metabolites in postpartum Brown Swiss cows and their effect on the presence of subclinical ketosis and reproductive parameters. One hundred cows from four farms in the Mantaro Valley (Junín, Perú) were grouped according to parity (1, 2, 3 and 4). The variables of the metabolic profile (total proteins, blood urea nitrogen [BUN], glucose, βhydroxybutyrate [B-HB]), milk production and body condition were estimated between 7 to 60 days postpartum in 7-day intervals. Likewise, the calving-first heat interval and the pregnancy rate at first service were recorded. The determination of subclinical ketosis was based on a semi-quantitative analysis by levels of B-HB in milk (µmol/l) using a commercial kit. BUN levels ranged between 11.74 and 15.92 mg/dl, being higher in fourth parity cows (p

Retained placenta (RP) is a common complication of bovine parturition. It is a multifactorial reproductive disorder that predisposes to infection and hence, to infertility. The impact of body condition changes during the transition period on the risk of RP appearance was evaluated in 12 Holstein dairy cows calving from October to January in north-eastern Algeria. The animals were body condition scored (BCS) 3 weeks antepartum and two weeks postpartum to assess the peripartum body fat loss (BCS loss). The statistical analysis involving variables related to BCS and parity was performed using the principal component analysis (PCA). An RP critical occurrence of 41.66% exceeding significantly the threshold prevalence of 10% (p

Background. The resumption of ovarian activity after parturition is related to reproductive efficiency. Objective. To determine the effect of breed group and some non-genetic factor on resumption of ovarian activity and pregnancy rate of dual-purpose cows. Methodology. In study 1, 37 cows were sampled biweekly, from the day 15 to 150 postpartum or until a corpus luteum (CL) was detected. Follicular population (FP), maximum follicle diameter (MFD) and maximum CL diameter (MCLD) were also measured. In study 2, 71 cows were pregnancy diagnosed. Chi2 tests and analyses of variance were performed to determine the effects of breed group, parity number, body condition score (BCS), BCS change (BCSC) and body weight change (BWC) on the dependent variables. Results. In study 1, aproximately, 84% of cows resumed ovarian activity at 68.3 days. More CL were found in multiparous cows (92.59%) and those with BCS ≥3.0 (95.83%). No differences were found in the FP and MFD. F1 cows had the largest MCLD (19.51 mm). In study 2, pregnancy rate was higher in cows with 2-3 (47.83%) and ≥4 parities (54.55%), F1 (54.29%) cows, those gaining BCS (64.29%) and high body weight (66.67%). Implications. Results suggest that primiparous cows and those with BCS ≤2.5 require better management; therefore, strategies must be established to improve reproductive efficiency. Conclusion. Primiparous and cows with BCS ≤2.5 delayed the first ovulation. Multiparous, F1 cows, those gaining BCS and body weight after calving had the highest pregnancy rate.

In this article, it was reviewed as the postpartum negative energy balance (NEB) affects the health and the reproductive efficiency of water buffaloes. The increase in the world buffalo population has been accompanied by an improvement in the milk yield per lactation and this could be causing negative consequences for health and reproductive efficiency, although there are still few studies about this relationship. Higher milk yield without the corresponding increase in the dry matter and energy intake can intensify the NEB, increasing weight and body condition loss, and this implies a decrease in glucose, insulin and insulin-like growth factor 1 (IGF-1) levels and the increases of non-esterified fatty acids (NEFAs) and β-hydroxybutyrate (BHB). This scenario may imply a greater susceptibility to diseases such as placental retention, endometritis, metritis and mastitis, as well as a longer period of anestrus, lower fertility and the lengthening of the interval to conception. To solve this situation, it is necessary to guarantee a good body condition at calving, and a high dry matter intake that allows reducing weight loss and body condition and different management, feeding and genetic alternatives are proposed.

ABSTRACT The aim of this study was to determine biometric measurements in vivo and in the carcass of Santa Ines lambs fed dehydrated brewery residue. Thirty-five Santa Ines lambs were used, approximately 70 days of age and with a mean initial body weight of 16.00±1.69 kg. The experimental design was completely randomised, with five levels of dehydrated brewery residue - DBR (0; 20; 40; 60 and 80%) added to the concentrated portion of the diet, with seven replications. The experimental diets consisted of Tifton-85 hay, soybean meal, ground maize, dehydrated brewery residue in the experimental proportions, dicalcium phosphate and a mineral base. The body condition score, thoracic girth and croup width were not influenced by the experimental diets, neither were the carcass measurements, except for croup circumference, chest width and leg compactness index (P>0.05). However, there was a decreasing linear effect on the carcass compactness index and ribeye area as the DBR was added to the diet. The morphometric measurements of croup height and width, and chest width can be used as an alternative for estimating the body weight at slaughter and the cold- carcass weight of Santa Inês lambs fed dehydrated brewery residue, as they show a high correlation with these variables.

A reproductive characterization of culled native cows was performed to three herds in Huambo province, Angola. The study made in June revealed that 54 of all the cows evaluated (331) in the three herds were culled animals (24, 17, and 3 per herd, respectively). Age, body condition (BC), total calving (TC), and calving interval (CI) were determined. General descriptive statistics was performed, and the factor studied was the herd. Age was distributed normally and the herds were compared through ANOVA, and Tukey for multiple comparison of means. The other variables (BC, TC, and CI) were evaluated through the Krustall Wallis method and U-Mann-Whitney statistics. The general age mean was 8.15±1.80, and the medians for BC, TC, and CI were, 2.5, 3.0, and 730.0, respectively. Overall, the results were distant from the optimal values of reproduction. The BC (P

The body condition index is a measure that attempts to describe energy storage compared to body length. This research was carried out with the aim of obtaining a body condition index in Ctenosaura pectinata. We used 40 adult females distributed between two groups. The iguanas were fed with four types of commercial food. They were also weighed in grams, their body lengths were measured in centimeters (total, snout-vent and head), body diameters were measured in centimeters (tail base, hip, leg, and pelvis) and body volume was measured in milliliters. Descriptive statistics were performed and variables were checked for normality. A Pearson correlation analysis was carried out to identify any related variables. A body condition index classification was obtained from the mean value and standard deviation (I: 2S-µ, II: S-µ, III: µ+S and IV: µ+2S) and a prediction equation for volume was obtained by Stepwise analysis. The body condition index turned to be highly accurate (r=0.98, pË‚0.0001). A body condition index classification in black iguana (Ctenosaura pectinata) was established, which will be useful for monitoring the body reserves of the species. Highlights: Body condition is a method to evaluate the reserves of animal fat tissues in their productive and reproductive states. In reptiles body conditions affects the females survival, egg size, and brood size, but it is not known in black iguana due to lack of information. Reproductive females black iguana classified as I (lean) and IV (excessively corpulent) presented non-reproductive conditions in captive condition.

The present study determined the relationship between body mass index (BMI) and chemical components in Pelibuey ewes. The BMI was determined in 28 ewes. At slaughter, internal organs and blood were weighed, then were mixed and grounded. The half-carcasses were dissected into subcutaneous and intermuscular fat, muscle, and bone. The muscle and fat of each animal were ground together, and one sample of the mixture was taken. The carcass and viscera samples were freeze-dried and further analysed for crude protein (CP), fat (F), and ash (A). The relationship between BMI and body composition were estimated using correlation coefficients (r) and regression models. The r between BMI and carcass crude protein and visceral crude protein were 0.51 and 0.48, respectively (p < 0.001), and between BMI and carcass F and visceral F were 0.82 and 0.71,respectively (p < 0.0001). The r2 of the models relating to BMI and body chemical components ranged from 0.62 to 0.97. There was a quadratic relationship between total body CP, and A. The chemical carcass components (CP, F, and carcass energy [CE]) showed a linear relationship with BMI, with an r2 ranging from 0.67 to 0.96. It was concluded that BMI could be used as predictors of body chemical composition in non-pregnant and non-lactating Pelibuey ewes. The use of empty body weight for calculating BMI yielded more accurate estimates of the chemical components of the body of adult sheep.

The American alligator (Alligator mississippiensis) is an effective indicator for restoration of more natural patterns of water levels and flows through the Everglades. The Florida Everglades is a highly modified system, so monitoring health of alligators can inform how different areas of this large ecosystem are doing. Based on an increase in reports of very skinny alligators, biologists and natural resource managers are seeking help from the public to better understand where and when this problem occurs. This fact sheet serves as a guide for citizen scientists on how to score alligator body condition and report sightings of very skinny or unhealthy alligators. http://edis.ifas.ufl.edu/uw460

The aim of this study was to evaluate the relationship between body ultrasound measurements (USM) and carcass energy content (CEC) of Pelibuey ewes. USM were taken 24 h before slaughter in twenty-two ewes. Fat thickness (FT) and Longissimus dorsi area (LDA) were determined in the thoracic (TFT and TLDA) and lumbar region (LFT and LLDA). CEC was considered as the sum of the energy of muscle and adipose tissues in the carcass. The correlation coecient (r) between body weight (BW) and CEC was 0.89 (p < 0.001). Nonetheless, correlations for LDA and CEC were not signicant (p > 0.05). The r2 for equation including BW and LFT was 0.87 (RSD= 15.34). The inclusion of LFT improved the prediction by about 8 %. The use of some USM in combination with BW provides good CEC estimates in Pelibuey ewes

The effect of two treatments, farms, and body shape on the size of the follicle and Corpus Luteum were evaluated. D-Cloprostenol (150 ug) was used in one of the treatments; in the other, D-Cloprostenol (150 ug) and Estradiol Ben-zoate (1 mg), were used. Two groups of 32 Holstein dairy cows each, from the Nero and Irquis farms in Cuenca, Ec-uador, were set up. Body condition (2.75-3.50) was considered. The calving number was 1-6; the farms, Irquis and Nero; and animal age, 3-10 years. Ultrasound scanning was used on days 0; 3 and 7, in order to measure the Luteum first, then the dominant ovarian follicle, and finally, the Corpus Luteum. Factor analysis of variance was performed. No significant differences were found for follicle size due to any factors; nor due to interaction. Concerning luteum, significant differences (P < 0.05) were observed for the treatments and for the farm. The values were 0.33 cm higher for the treatment with Benzoate, and 0.36 cm, at Irquis, in comparison to Nero. The treatment with Benzoate, along with better husbandry at Irquis played a critical role in the appearance and evolution of the luteum.

Predation and alteration of microhabitats may represent high risk for nesting of Amazonian turtles. This study aimed at investigating the nesting and body parameters of neonates of Podocnemis unifilis in the Araguari River basin, State of Amapá, Brazil. The spawning sites of this turtle were monitored along the Falsino River (a region with two reserves) and in the urban area of the Porto Grande city along the Araguari River, from August to December 2011. A total of 180 nests were found and the nesting occurred from September to November, with prevalence in October. Eggs hatching occurred in December. The mean incubation period was 63.5 ± 5.2 days and the eggs hatching success was 25%. However, approximately 80% of the nests had suffered predation mainly by humans, which occurred in both the protected areas of the reserves and the urban area. The pattern of nesting site choice was discussed. Egg size was larger than that previously described for the same turtle species in the other regions. The body condition index of neonates indicated a good use of vitelline reserves. The results indicate the urgent need for strategic actions to conserve and maintain the natural stocks of this relatively vulnerable turtle in the region.

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 the date of calving, cows were divided into three blocks, with intervals of 20 days between blocks. The body condition (BC) of the cows was estimated subjectively on a scale from 0 to 5 points, with intermediate grading of 0.5 points. We measured the thickness of subcutaneous fat (SF) between the 12th and 13th ribs and rump by ultrasound. Blood samples from each cow were collected weekly from the third week after birth until weaning, to analyze the level of progesterone; in the samples collected until 16 weeks postpartum, we analyzed the concentration of nonesterified fatty acids (NEFA). The gestation period of mothers of NEL calves was eight days longer, on average. The variables relating to the mobilization of body reserves (NEFA, BC and SF) were not influenced by calf GG, with the only significant effects being the number of days postpartum, with a peak in the concentration of NEFA between the sixth and eighth weeks and linear decrease in BC and NF. Mothers of NEL calves remained in anestrus for 4.6 weeks longer than the mothers of crossbred calves.

This experiment evaluated the performance of 84 Braford steers grazing on summer and winter cultivated pastures fed or not fed an energy-protein supplement. Steers were 10 months old and weighed, on average, 165 kg at the beginning of the trial. Steers grazed on cultivated winter pasture, consisting of black oats (Avena strigosa) and ryegrass (Lolium multiflorum Lam.), and then on cultivated summer pasture, consisting of Napier grass (Pennisetum purpureum). The following treatments were applied: SS - supplement was fed during both seasons; SN - supplement was fed only during the winter; NS - supplement was fed only during the summer; and NN - steers were not fed any supplement. Supplementation resulted in higher body weight and better body condition score (SS: 369.2 and 4.52; SN: 335.2 and 4.01; NS: 352.5 and 4.49; SS: 322.5 and 3.83). Longissimus dorsi area was larger in supplemented steers, which also presented thicker backfat when compared with those not fed any supplement (3.67 and 2.29 mm, respectively).

The response of energy supplementation was evaluated on the development and reproductive performance of beef heifers on temperate grasslands. Twenty-eight Charolais × Nellore heifers, with initial average age of 18 months and initial live weight of 274.9 kg were utilized. The animals were maintained on oat + ryegrass pasture and distributed in the following treatments: no supplementation (NS): heifers kept exclusively on pasture; MEG: supplementation with protected fat Megalac®; BRM: supplementation with brown rice meal; BRM+MEG: supplementation with BRM + protected fat. The average final weight of the heifers was of 403.4 kg and corresponded to 89.5% of the adult weight. The body condition of heifers increased linearly with daily increase of 0.012 points, correlating positively with the final weight. There was interaction between treatment and period for average daily weight gain. The highest daily weight gain, 1.395 kg, occurred in the first period when the animals were supplemented with BRM+MEG. In the last period, the NS animals presented the lowest daily weight gain, 0.888 kg. Supplementation with brown rice meal and/or protected fat does not interfere in the intake of pasture by heifers or increase the total intake of dry matter, not changing, therefore, the average daily weight gain at the end of the period of grazing. The daily weight gain does not change during supplementation. The use of temperate pasture with and without supplementation promotes the proper development of the structure and reproductive tract of heifers, benefiting the animal performance indexes in the first mating at 25-27 months of age.

This study was conducted to evaluate body fat reserves (BFD) and their relationship to ultrasound back fat thickness (BFT) measurements in twenty Pelibuey ewes. The BFT was determined 24 h before slaughter using real-time ultrasound equipment with a 6/8 MHz probe. At slaughter, internal fat (TIF) was dissected and weighed. The carcasses were split into two halves, weighed and chilled (6◦C for 24 h). The left half-carcasses were completely dissected into muscle, bone and subcutaneous and intermuscular fat (carcass fat, TCF), and weighed separately. The r values for BFT and BFD ranged from 0.39 to 0.72. Regression equations between BFT and BFD had an R2 ranging from 0.15 to 0.52. Using BFT to predict BFD in Pelibuey ewes was poorly correlated.

El crecimiento de la agricultura produce perdida del habitat natural, con consecuencias para la biodiversidad de los anfibios. Se analizo la dieta y condición corporal de larvas de anuros de Rhinella arenarum que habitan agroecosistemas. Los muestreos fueron realizados en dos agroecosistemas y en un tercer sitio, no afectado por cultivos. Las larvas capturadas fueron anestesiadas, fijadas y preservadas en formaldehido, se realizaron medidas corporales y se analizo la dieta de las larvas. Se registro diversidad en la oferta alimenticia proporcionada por los distintos ambientes. La dieta tuvo una predominancia de algas Bacillarophyceae, seguidas por Cyanophyceae. Particularmente, los géneros Navicula, Nitzschia, Hantzschia y Gomphonema (clase Bacillarophyceae), fueron importantes en los agroecosistemas. Los géneros Osillatoria, Euglena y Strombomonas (clases Cyanophyceae y Euglenophyceae), predominaron en la dieta de las larvas de anuros en el sitio menos alterado. Las larvas de los sitios más alterados consumen menor cantidad de alimento y registran una menor condición corporal. La presencia de determinadas algas, indicarían un mayor grado de contaminación en los agroecosistemas. La eutrofización de lagunas podría alterar la disponibilidad de alimento para larvas de anuros que podría tener consecuencias poblacionales negativas. Se sugiere el análisis de dietas larvarias como un potencial bioindicador de salubridad ambiental.Trophic ecology in tadpoles of Rhinella arenarum (Anura: Bufonidae) in agroecosystems and their possible implications for conservation. The progress of the agriculture border has led an important loss of natural habitats, with significant consequences for biodiversity. In this sense, the studies in anuran amphibian tadpoles inhabiting these environments are relevant, because the larval stage is a phase of population regulation. The aim of this study was to analyze the body condition and diet in Rhinella arenarum, tadpoles, an anuran species widely distributed in South America and that inhabit agroecosystems. Three sites were sampled, two agroecosystems with different alteration degrees (C1 and C2) and an uncultured (SM) third place. The captured tadpoles were anesthetized, fixed and preserved in formaldehyde (10%). Subsequently, body measurements were made and the complete intestine was removed and analyzed for food items under a binocular microscope. The diet in R. arenarum tadpoles has a dominance of algae Bacillariophyceae, followed by Cyanophyceae. In particular, the class Bacillariophyceae, due to the presence of the genus Navicula, Nitzschia, Gomphonema and Hantzschia, was important in the diet of the anurans in those agroecosystems. Class Cyanophyceae, mainly represented by genus Oscillatoria and Euglenophyceae represented by Euglena and Strombomonas, were predominant in the diet of the anurans in SM. Some differences in the total items consumed by tadpole were observed between the studied sites. Tadpoles that inhabit the modified sites (C1 and C2) recorded a significantly smaller amount of food. Moreover, the tadpoles that inhabit these sites showed a lower body condition. The presence of certain algae associated with eutrophic environments, could indicate some pollution in agroecosystems (C1 and C2). Food resources would be lesser in places with strong agricultural activity, possibly with a greater degree of eutrophication. A smaller food amount could have consequences at population level for the short and long time terms, because of its impact on individual growth. Larval diet is suggested as a potential bioindicator of environmental health for these areas. Rev. Biol. Trop. 60 (2): 771-779. Epub 2012 June 01.

The objective of this study was to evaluate the influence of feeding energy levels during the last third of gestation and lactation on performance of ewes and lambs up to weaning. The experiment was carried out in the sheep raising sector of Universidade Estadual de Londrina (UEL), from August to December of 2007. Thirty-two adult lambs with 105 days of gestation, average live weight of 57.55 kg and average body condition scores of 3.42 were used in the beginning of the experiment. The animals were confined in collective pens, distributed randomly in three treatments: 2.4; 2.2 and 2.0 Mcal of metabolizable energy (ME)/kg of dry matter (DM). Feed supply was ad libitum during the last third of gestation and lactation. Weaning occurred at 70 days. Body weight, body condition score and milk production of ewes and body weight of the lambs were analyzed. There were no significant differences for body weight and body condition of ewes at lambing; however, the level of 2.4 Mcal enabled better results for those characteristics at weaning and higher gain in weight and body condition scoring during the experiment. Severe energetic restriction (2.0 Mcal ME/kg DM) determined lower average daily milk production. Lambs from levels 2.4 and 2.2 presented similar weights in all measurements and were superior to those in level 2.0. Lambs from level 2.4 presented higher average weight gain from birth to weaning. The energetic restriction upon lambs at the end of gestation and during lactation limits the performance of ewes and lambs up to weaning.

Avaliou-se o desempenho de novilhas de corte até o parto submetidas a diferentes níveis de suplementação em pastagem natural durante o primeiro período reprodutivo, dos 14 aos 17 meses. Foram utilizadas 98 novilhas contemporâneas do mesmo rebanho dos grupos genéticos Charolês, Nelore e suas cruzas, com peso médio de 255 kg. As novilhas foram distribuídas em três grupos: sem suplementação; com suplementação de 3,5 g/kg do peso corporal; com suplementação de 7,0 g/kg do peso corporal. O peso ao final e o ganho de peso médio diário durante o período de suplementação foi maior entre as novilhas do grupo com suplementação na proporção de 7,0 g/kg (322 e 0,701 kg) em comparação àquelas sob suplementação na proporção de 3,5 g/kg (302 e 0,464 kg) e sem suplementação (288 e 0,425 kg), que não diferiram entre si. O escore de condição corporal ao final da suplementação diferiu entre os três grupos com 3,07; 3,33 e 3,47 pontos, respectivamente, para novilhas sem suplementação; com suplementação na proporção de 3,5 g/kg do peso corporal; com suplementação na proporção de 7,0 g/kg do peso corporal. A porcentagem de prenhez foi influenciada significativamente pelo nível de suplementação, sendo de 35,0; 34,2 e 70,0%, respectivamente. Os dois grupos sob suplementação tiveram maior taxa de concepção na metade inicial do período reprodutivo. A média de idade das novilhas ao parto foi de 785, 778 e 761 dias, respectivamente. O ganho médio diário e a condição corporal foram semelhantes entre as novilhas dos dois grupos genéticos, porém o peso ao início e ao final do período de suplementação foi maior nas filhas de touros charoleses em relação às de touros nelores, refletindo-se nas taxas de manifestação de estro (68,8 vs. 38,2) e de prenhez (60,9 vs. 26,5). As características relacionadas ao parto das novilhas não foram influenciadas pelos níveis de suplementação durante o período reprodutivo. A suplementação durante o período de acasalamento aumenta o desempenho reprodutivo de novilhas aos 14 meses de idade.The objective was to evaluate the performance of beef heifers until calving receiving different levels of supplementation on native pasture during the first breeding season, from 14 to 17 months: no supplementation; 3.5 g/kg of body weight; and 7.0 g/kg of body weight. Ninety-eight Charolais, Nellore and their crosses, with average initial weight of 255 kg, were used. Weight at the end and average daily weight gain during the supplementation period were higher for 7.0 g/kg of supplement heifers (322 and 0.701 kg) compared to those with 3.5 g/kg of supplement (302 and 0.464 kg) and heifers without supplementation (288 and 0.425 kg), which did not differ from each other. Body condition score at the end of the supplementation was different between the three treatments, being 3.03, 3.33 and 3.47 points for heifers without supplementation; 3.5 g/kg of body weight; and 7.0 g/kg of body weight, respectively. Pregnancy rate was significantly affected by supplementation level, being 35.0, 34.2 and 70.0%, respectively. Heifers of the two supplementation treatments had higher conception rate at the first half of the reproductive period. Average heifer ages at calving were of 785, 778 and 761 days, respectively. The average daily weight and body condition of the heifers of the two genetic groups were similar; however, the initial and final weight of the supplementation period was higher for Charolais bulls daughters, compared with Nellore bulls daughters, reflecting on the heat (68.8 vs. 38.2%) and pregnancy (60.9 vs. 26.5%) rates. Characteristics related to calving were not affected by the supplementation levels during the reproductive period. The supplementation during the first breeding season increases reproductive performance of heifers at 14 months of age.

This study evaluated yearling growth and reproductive performance of Hereford heifers at 24-26 months of age grazing on natural pastures at two stocking rates during winter and spring, associated or not to improved natural pastures. Heifers were classified according to three weight groups (Light, Medium and Heavy) and randomly distributed into four feeding management practices: 0.6 AU (1 animal unit = 450-kg body weight) - heifers on natural pastures at a stocking rate of 0.6 AU/ha; 0.8 AU - heifers on natural pastures at a stocking rate of 0.8 AU/ha; 0.6 AUI - heifers on natural pastures at a stocking rate of 0.6 AU/ha and on improved natural pastures between Sept 1st and Nov 1st; 0.8 AUI - heifers on natural pasture at a stocking rate of 0.8 AU/ha and on improved natural pastures between Sept 1st and Nov 1st. The stocking rate of 0.8 AU resulted in significant weight loss during winter months (-0.138 and -0.356 kg for 0.6 and 0.8 AU, respectively). Heifers grazing during the spring on improved natural pastures presented higher weight gain before the breeding season and higher body weight and body condition score in the beginning and end of the breeding season in relation to those grazing only on natural pastures. Heifers kept at 0.6 AU/ha obtained 69.7% pregnancy rate, which was significantly higher than the 54.2% of those managed at 0.8 UA/ha. Heifers grazing on improved natural pastures during the spring achieved 83.8% pregnancy rate, whereas those maintained on natural pastures achieved only 40.2%. Light and medium heifers lost less weight during the winter as compared with the heavy ones, but weight differences between groups remained until the end of the breeding season. Heavy heifers have higher pregnancy rates. Heifers submitted to lower stocking rate and those grazing on improved natural pastures conceive earlier.

En este estudio se determinó los niveles de metales pesados (Cd, Pb, Zn, Cu, Cr y Ni) en el tejido renal del delfín franciscana, Pontoporia blainvillei, y se estableció la influencia de los parámetros ecológicos y biológicos sobre la bioacumulación de estos elementos. Se analizaron muestras de 38 ejemplares colectados entre 2004 y 2010 en el sur de Buenos Aires, Argentina. La edad de los animales y el estado de madurez sexual se determinaron por métodos histológicos, y los niveles de metales pesados por Espectrofotometría de Absorción Atómica. No se determinaron diferencias significativas para las concentraciones de Zn, Cu y Cd entre ambos sexos. Los niveles de Cd presentaron diferencias según el estado de madurez sexual y se relacionaron positivamente con la longitud, peso corporal y edad. Los niveles de Cd, Cu y Zn resultaron menores a los informados en estudios previos realizados en el norte de Buenos Aires y Uruguay.Heavy metal (Cd, Pb, Zn, Cu, Cr,Ni) concentrations were determined in the kidney tissue of the Franciscana dolphin, Pontoporia blainvillei, and the influence of ecological and biological parameters on the bioaccumulation of these elements was established. Samples from 38 specimens, collected between 2004 and 2010 off southern Buenos Aires, Argentina, were analyzed. Histological methods were used to determine both the age and sexual maturity of the animals. Heavy metal concentrations were measured by atomic absorption spectrophotometry. No significant differences were found by sex for Zn, Cu, and Cd. However, Cd levels differed between maturity stages and were positively related to length, body weight, and age. The Cd, Cu, and Zn levels reported here in were lower than those included in previous studies done off northern Buenos Aires and Uruguay.

Este trabalho foi realizado para avaliar o desempenho produtivo e reprodutivo de 52 vacas de corte mestiças Charolês × Nelore em pastagem natural. O experimento foi iniciado em 4/8/2003, quando as vacas em gestação foram distribuídas uniformemente por peso e condição corporal em duas cargas animais (280 e 360 kg PV/ha). O desmame precoce foi realizado em 26 vacas quando os bezerros(as) atingiram em média 100 dias de idade e o desmame convencional, em 26 vacas quando os bezerros(as) atingiram em média 180 dias de idade. As vacas submetidas ao desmame precoce tiveram maior ganho médio diário em comparação àquelas submetidas ao desmame convencional (0,471 vs. 0,255 kg/dia, respectivamente). Houve interação significativa entre as idades de desmame e os períodos para a condição corporal das vacas. As vacas submetidas ao desmame precoce apresentaram melhor condição corporal na época do desmame convencional (3,5 vs. 2,8) e ao final do acasalamento (3,0 vs. 2,8). A carga animal não afetou significativamente o ganho médio diário nem a condição corporal das vacas. A taxa de prenhez das vacas do desmame precoce (60,0%) foi significativamente superior à do desmame convencional (12,0%), no entanto, as cargas animais não diferiram entre si (7,7% vs. 15,4%, respectivamente). Nos bezerros submetidos ao desmame precoce, o ganho médio diário e o peso vivo aos 180 dias foram significativamente inferiores aos observados nos bezerros do desmame convencional. O manejo da pastagem com as duas cargas animais no pós-parto das vacas e as duas idades de desmame dos bezerros não influenciam o peso médio e o ganho médio diário dos bezerros até os 14 meses de idade.The study was conducted to evaluate productive and reproductive performance of 52 crossbred Charolais × Nellore beef cows on natural pasture. The experiment started on August 04, 2003, when pregnant cows were uniformly distributed by weight and body condition at two stocking rates (CA280 = 280 kg LW/ha and CA360 = 360 kg LW/ha). Early weaning was imposed to 26 cows when calves reached average of 100 days of age and conventional weaning, when calves were approximately 180 days old. Cows submitted to early weaning had average daily gain higher than cows submitted to conventional weaning (0.539 vs. 0.257 kg/day, respectively). There was significant interaction between weaning ages and periods for body condition of cows. Cows submitted to early weaning presented higher body condition at conventional weaning (3.5 vs. 2.8) and at the end of mating period (3.0 vs. 2.8) than the conventional weaning. The stocking rate did not significantly affect the average daily gain and body condition of cows (CA280 = 0.101 kg/day, 2.7 and CA360 = 0.214 kg/day, 2.7, respectively). The pregnancy rate of cows under early weaning (60.0%) was significantly better than for those under conventional weaning (12.0%); however, the stocking rates did not differ (CA280 = 7.7% vs. CA360 = 15.4%). In calves submitted to early weaning, average daily gain and live weight at 180 days were significantly lower than those of calves at conventional weaning. The post-partum management of cows and two ages of weaning calves evaluated did not affect the development of calves until 14 months of age.

Avaliou-se o desenvolvimento de bezerros de corte submetidos a duas idades de desmame: precoce, em média com 80 dias de idade; convencional, em média com 152 dias de idade. Foram utilizados 105 bezerros Braford, nascidos nos anos de 2004 e 2005. Após o desmame, os bezerros foram mantidos em pastagens cultivadas de milheto (Pennisetum americanum) no primeiro e segundo verão e, no inverno/primavera, de aveia e azevém (Avena strigosa Schreb + Lolium multiflorum Lam). Foram avaliados os pesos corporais, ganhos de pesos médios diários e condição corporal. Houve interação significativa entre idade de desmame e ano para o ganho médio diário, tanto no desmame precoce como no desmame convencional, na pastagem de aveia e na de azevém. No período entre as duas idades de desmame, o ganho médio diário no desmame precoce foi maior em 2004 que em 2005 (0,499 vs 0,468 kg, respectivamente) e no desmame precoce ocorreu maior ganho médio diário em 2005 (0,493 vs 0,631 kg, respectivamente). Na pastagem de aveia e azevém, o ganho médio diário dos animais do desmame precoce em 2004 (0,666 kg) foi menor que em 2005 (0,760 kg), no entanto, não houve diferença entre os anos no caso dos animais do desmame convencional (0,720 e 0,723 kg, respectivamente). Durante os segundos verões, não houve diferença no ganho médio diário dos animais entre os desmames precoce e convencional. O peso dos animais do desmame precoce (158,2 kg) foi superior ao daqueles do desmame convencional (147,7 kg) no início da pastagem de inverno, porém, não diferiu no final. Ao final do verão, quando os novilhos atingiram 15-16 meses de idade, o peso corporal foi similar entre os desmames precoce (340,1 kg e 4,14 pontos) e convencional (332,8 kg e 4,15 pontos). A condição corporal final em 2004 foi maior (4,34) que em 2005 (3,96 pontos). Bezerros desmamados aos 80 dias de idade e alimentados adequadamente têm desempenho semelhante aos desmamados aos 152 dias de idade, atingindo desenvolvimento e acabamento adequados de abate para mercados específicos aos 15-16 meses de idade.The performance of beef calves submitted to two weaning ages (early weaning, at an average age of 80 days; conventional weaning, at an average age of 152 days) was evaluated. One hundred and five Braford calves born in 2004 and 2005, after weaning, were kept on pastures cultivated with pearl millet (Pennisetum americanum) in the first and second summer and, in winter/spring, they were kept on pastures with oat and ryegrass (Avena strigosa Schreb + Lolium multiflorum Lam). Body weight (BW), average daily weight gain (ADWG) and body condition (BC) were evaluated. There was a significant interaction among age at weaning and year for daily weight gain for early weaning as well as for conventional weaning on oat and ryegrass pastures. In the period between the two weaning ages, the daily weight gain in early weaning was higher in 2004 than in 2005 (0.499 vs 0.468 kg, respectively) and for early weaning, higher daily weight gain occurred in 2005 (0.493 vs. 0.631 kg, respectively). On oat and ryegrass pasture, average daily weight gain for early weaned animals in 2004 (0.666 kg) was lower than in 2005 (0.760 kg), however, there was no difference among years for conventional weaned animals (0.720 and 0.723 kg, respectively). During second summer periods, average daily weight gain did not differ among early and conventional weaned animals. Weight of early weaned animals (158.2 kg) was higher than conventional weaned animals (147.7 kg) in the beginning of winter grazing; however, it did not differ at the end. In the end of the summer, when calves were 15-16 months of age, body weight was similar among early weaned (340.1 and 4.14 points) and conventional (332.8 kg and 4.15 points) weaned animals. Final body condition, in 2004, was higher (4.34) than in 2005 (3.96 points). Calves weaned at 80 days of age and adequately fed present similar development as those weaned at 152 days of age, achieving development and finishing conditions to be slaughtered for specific markets at 15-16 months of age.

During pre and post calving periods, it was evaluated the influence of the following forage systems on reproductive performance of primiparous cows: natural pasture during pre and post-calving periods; natural pastures during pre-calving period and improved pastures during post-calving period; improved pastures during pre-calving and natural pasture during post-calving; improved pasture during pre- and post-calving periods. The lowest body weights and body condition scores were observed on cows kept on natural pastures pre-calving (384.3 kg and 3.31; 391.4 kg and 3.60), followed by those on improved pastures during pre-calving and on natural pasture during post-calving period (424.4 kg and 3.60), finally, cows on improved pasture during pre- and post-calving period (421.2 kg and 3.59). Cows on improved pastures pre and post-calving showed higher body weight and body condition score in the beginning of the breeding season (442.1 kg and 3.76), higher pregnancy rate (82.3%) and they conceived earlier. Natural system during pre-calving and improved on post-calving and that with improved pasture in pre-calving and natural in post-calving did not differ on weight at the beginning of breeding season (417.2 and 409.8 kg) and on pregnancy rate (65.8 and 62.8%), respectively. However, cows on natural pasture in pre-calving and on improved pasture in post-calving conceived earlier. Cows on natural pastures showed lower weight in the beginning of breeding season (391.2 kg), the lowest pregnancy rate (52.7%), and they conceived later. Cows maintained on improved pastures pre- and post-calving improved weight and body condition score at calving and beginning of the breeding season making high reproductive performance possible.Durante os períodos pré e pós-parto, foi avaliada a influência de sistemas forrageiros no desempenho reprodutivo de vacas primíparas: pastagem natural nos períodos pré e pós-parto; pastagem natural no pré-parto e pastagem melhorada no pós-parto; pastagem melhorada no pré-parto e pastagem natural no pós-parto; pastagem melhorada nos períodos pré e pós-parto. Os menores pesos e condições corporais foram observados nas vacas mantidas em pastagem natural no pré-parto, (384,3 kg e 3,31; 391,4 kg e 3,60), seguidas daquelas em pastagem melhorada no pré-parto e natural no pós-parto (424,4 kg e 3,60); e, por ultimo, das vacas em pastagem melhorada no pré e pós- parto (421,2 kg e 3,59). As vacas em pastagem melhorada no pré e pós-parto tiveram maior peso e condição corporal ao início do acasalamento (442,1 kg e 3,76), maior taxa de prenhez (82,3%) e emprenharam mais cedo. Os sistemas com pastagem natural no pré-parto e melhorada no pós-parto e aquele com pastagem melhorada no pré-parto e natural no pós-parto não diferiram quanto a peso ao início do acasalamento (417,2 e 409,8 kg) e taxa de prenhez (65,8 e 62,8%), respectivamente. Entretanto, as vacas em pastagem natural no pré-parto e melhorada no pós-parto emprenharam mais cedo. As vacas mantidas em pastagem natural tiveram o menor peso ao início do acasalamento (391,2 kg), a menor taxa de prenhez (52,7%) e emprenharam mais tarde. Pastagens melhoradas no pré e pós-parto melhoraram os pesos e as condições corporais ao parto e ao início da reprodução, possibilitando alto desempenho reprodutivo.

This study evaluated body development and reproductive performance of beef cows whose calves were submitted to early weaning (76 days of age), or conventional weaning (148 days of age). It was used 141 Braford cows that calved in 2004, 2005, and 2006 to evaluate weight at calving at 76 days, weight at calving at 148 days, weight at the beginning and end of the breeding season, variation of the average daily weight, body condition, pregnancy rate, and calving interval. Dams of calves weaned at 148 days of age showed daily weight gain higher body weight and better body condition at 148 days of age. The weights at the end of breeding season and average weight gain during the breeding season were higher in early weaning cows than in conventional cows. Pregnancy rate of early weaning cows (86.34%) was higher than those submitted to weaning at conventional age (55.45%). Pasture interval was similar among early weaning cows and conventional weaning cows. The best benefit on reducing weaning age in pregnancy rate was in primiparous cows. There was significant interaction between weaning age and the year for calving interval and milk production. The early weaning of calves carried out at 76 days of age allows cows to better weight recovery in the post-weaning and breeding periods, improving their body condition and consequently increasing pregnancy rate regarding to cows whose calves suckled until 148 days of age.Avaliaram-se o desenvolvimento somático e o desempenho reprodutivo de vacas de corte cujos bezerros foram submetidos ao desmame precoce (76 dias de idade) ou à idade convencional (aos 148 dias de idade). Foram utilizadas 141 vacas Braford paridas nos anos de 2004, 2005 e 2006 para avaliação dos pesos ao parto, aos 76 dias, aos 148 dias, ao início e fim do período reprodutivo, da variação de peso médio diário, da condição corporal, da taxa de prenhez e do intervalo de partos. As vacas mães dos bezerros desmamados aos 148 dias tiveram maior ganho médio diário, maior peso e melhor condição corporal aos 148 dias. O peso ao fim do período reprodutivo e o ganho médio diário durante o período reprodutivo foram maiores nas vacas do desmame precoce. A taxa de prenhez das vacas do desmame precoce (86,34%) também foi superior à das vacas submetidas ao desmame em idade convencional (55,45%). O intervalo de parto foi semelhante entre vacas do desmame precoce e aquelas do desmame em idade convencional. O maior benefício da redução da idade de desmame na taxa de prenhez observado foi nas vacas primíparas. Houve interação significativa entre a idade de desmame e o ano para intervalo de partos e produção de leite. O desmame precoce dos bezerros realizado aos 76 dias de idade permite às vacas maior recuperação do peso nos períodos pós-desmame e reprodutivo, melhorando sua condição corporal e aumentando a taxa de prenhez em relação às vacas mantidas em amamentação até os 148 dias de idade.

The effects of weaning age (90 days or 156 days) of female beef calves were evaluated on their subsequent performance from the beginning of the first pregnancy and the end of the second breeding season, at 22/24 months of age. During pregnancy, heifers were managed as a single group on Brachiaria brizantha cv. Marandu pasture; after calving, on bristle oats (Avena strigosa Schreb) and ryegrass (Lolium multiflorum Lam.); and on Brachiaria humidicula pasture during the second reproductive period. The characteristics studied were not influenced by calf weaning age. Heifers submitted to early or conventional weaning weighed 354.5 and 351.9 kg in the post-calving, and 363.4 and 359.2 kg when they weaned their calves. Average daily gain during the breeding season was 0.562 kg, and body condition score was 3.10 and 3.93 at the beginning and end of the experiment, respectively. Average calf birth and weaning weights were not influenced by dam weaning age, and were 28.7 ± 0.74; 86.5 ± 3.26 and 27.4 ± 0.92; 90.3 ± 4.04 kg, respectively, for dams submitted to early or conventional weaning. Dystocia, calving, birth, and weaning rates were not different between weaning ages, with mean values of 29.5; 95.3; 77.3 e 73.4%. Conception rates were 47.9% in the initial third and 40.8% in the second third versus 11.3% in the final third of the breeding season. Heifer average age at conception was 438 and 434 days for early weaning and conventional weaning. Pregnancy rates and production efficiency estimates at calving and calf weaning were not affected by heifer weaning age. Heifer early weaning did not affect their subsequent performance until the end of the second breeding season, at 22/24 months of age.Avaliaram-se os efeitos da idade de desmame (aos 90 dias e aos 156 dias) de bezerras de corte sobre o seu desempenho subsequente entre o início da primeira gestação e o final do segundo período reprodutivo, aos 22/24 meses de idade. Durante a gestação, as novilhas foram manejadas em grupo único em pastagem de Brachiaria brizantha cv. Marandu; após o parto, em pastagem de aveia (Avena strigosa Schreb) e azevém (Lolium multiflorum Lam.); e, no segundo período reprodutivo, em pastagem de Brachiaria humidicula. As características estudadas não foram influenciadas pela idade de desmame das bezerras. Os pesos vivos pós-parto foram de 354,5 e 351,9 kg e, ao desmame de seus bezerros, 363,4 e 359,2 kg para as bezerras submetidas aos desmames precoce e convencional. O ganho de peso médio diário no período reprodutivo foi 0,562 kg e o escore de condição corporal, de 3,10 no início e 3,93 no final do experimento. Os pesos médios dos bezerros no nascimento e no desmame não foram influenciados pela idade de desmame das mães, com valores de 28,7 ± 0,74; 86,5 ± 3,26 e 27,4 ± 0,92; 90,3 ± 4,04 kg, respectivamente, para as mães submetidas aos desmames precoce e convencional. As taxas de distocia, parição, natalidade e desmame não diferiram entre as idades de desmame, com valores médios de 29,5; 95,3; 77,3 e 73,4%. As taxas de concepção foram de 47,9% no terço inicial e 40,8% no terço intermediário e 11,3% no terço final do período reprodutivo. A idade média à concepção foi de 438 e 434 dias para as novilhas do desmame precoce e do desmame convencional. A taxa de prenhez e as estimativas de eficiência produtiva ao parto e ao desmame dos bezerros não foram alteradas pela idade de desmame das vacas quando bezerras. O desmame precoce de bezerras não afeta seu desempenho subsequente até o final do segundo período reprodutivo, aos 22/24 meses de idade.

Avaliou-se a influência do desmame precoce, em média aos 77 dias pós-parto, e do desmame convencional, em média aos 147 dias pós-parto, no desenvolvimento de novilhas de corte. Foram utilizadas 161 bezerras Braford, nascidas nos anos de 2004, 2005 e 2006. Após os desmames as bezerras foram mantidas em pastagens cultivadas de verão (Pennisetum americanum) e de inverno e primavera (Avena strigosa Schreb + Lolium multiflorum Lam). Foram avaliados os pesos corporais, ganhos de pesos médios diários e condição corporal a cada 28 dias. Houve interação entre idades de desmame e ano para peso corporal e ganho de peso. O desmame precoce não influenciou os pesos corporais, embora o peso corporal tenha sido menor aos 147 dias nos animais nascidos em 2005 e 2006. O ganho médio diário entre as idades de desmame foi similar nos três anos no desmame precoce (0,538; 0,477 e 0,472 kg, respectivamente) e aumentou significativamente no desmame convencional com o avançar dos anos (0,516; 0,704 e 1,040 kg, respectivamente). Na pastagem de Avena strigosa + Lolium multiflorum, o ganho médio diário foi similar entre idades de desmame. O peso no início do período reprodutivo no desmame precoce em 2004 (283,4 kg) foi maior que em 2005 (260,7 kg), enquanto no desmame convencional não houve diferença entre os anos (272,9 e 263,8 kg, respectivamente). A condição corporal no início do período reprodutivo foi afetada pelo ano de observação. A idade da bezerra esteve positivamente correlacionada com os pesos ao desmame convencional (r = 0,510) e ao início do período reprodutivo (r = 0,491). O desmame precoce e o convencional não inviabilizam o acasalamento das novilhas aos 14-/15 meses de idade.The influence of the early weaning, on average 77 days after the birth, or the conventional weaning, on average 147 days on beef heifer development was evaluated. One hundred and sixty-one Braford calves, born in 2004, 2005 and 2006 were kept after weaning on cultivated summer (Pennisetum americanum) and winter/spring (Avena strigosa Schreb and Lolium multiflorum Lam) cultivated pastures. Body weight, daily Body weight gain and body condition were assessed every 28 days. There was interaction between weaning age and year for body weight and weight gain. Early weaning did not influence body weight but the body weight was smaller at 147 days in the animals born in 2005 and 2006. The avegage daily gain between the weaning ages was similar in the three years for early weaning (0.538, 0.477 and 0.472 kg, respectively), but increased significantly in the conventional weaning as the years progressed (0.516, 0.704 and 1.040 kg respectively). The average daily weight gain on Avena strigosa + Lolium multiflorum pasture was similar for both treatments. The weight at the beginning of the reproduction period for early weaned heifers in 2004 (283.4 kg) was higher than in 2005 (260.7 kg), while for conventional weaning there was no difference between years (272.9 and 263.8 kg, respectively). The body condition at the beginning of the reproduction period was affected by the year of observation. Calf age was positively correlated to weight at conventional weaning (r = 0.510) and beginning of the reproduction period (r = 0.491). Both weaning ages showed the possibility of mating beef heifers at 14/15 months of age.

Este trabalho foi realizado com o objetivo de avaliar, por dois anos consecutivos, o efeito da idade de desmame no desempenho reprodutivo de 121 novilhas Braford acasaladas aos 13/15 meses de idade. Avaliaram-se duas idades de desmame - aos 77 dias pós-parto (desmame precoce); e aos 147 dias pós-parto (desmame convencional), utilizando-se 121 bezerras Braford nascidas nos anos de 2004 (66) e 2005 (55). Após o desmame, as bezerras foram mantidas, inicialmente, em pastagens cultivadas de verão (Pennisetum americanum, L.) e de inverno/primavera (Avena strigosa Schreb + Lolium multiflorum Lam). Foram avaliados o peso vivo (PV), a condição corporal (CC) e o ganho de peso médio diário (GMD) durante o período reprodutivo. O desmame precoce não ocasionou diferença significativa no peso ao início e ao final do período reprodutivo. As novilhas nascidas em 2005 apresentaram menor peso durante o período reprodutivo em relação às nascidas em 2004. O ano influenciou a condição corporal ao início e ao final do período reprodutivo, que foi, respectivamente, 4,16 e 4,29 pontos para as novilhas nascidas em 2004; e 3,57 e 3,38 pontos para as nascidas em 2005. A porcentagem de prenhez não foi influenciada pela idade de desmame (55,5 e 70,7% para novilhas do desmame precoce e as do desmame convencional, respectivamente) nem pelo ano (68,6% para novilhas nascidas em 2004 e 57,6% para as novilhas nascidas em 2005). As novilhas com diagnóstico de prenhez positivo tiveram maior desempenho reprodutivo durante a recria e o período de acasalamento em comparação àquelas com diagnóstico negativo. O desempenho reprodutivo das novilhas correlacionou-se positivamente com peso vivo e condição corporal ao início e ao final do período reprodutivo. O desmame precoce não afeta o desempenho reprodutivo de novilhas Braford aos 13/15 meses de idade.The objective of the study was to evaluate, for two consecutive years, the weaning age effect on the reproductive performance of 121 Bradford heifers mated at 13/15 months old. Two weaning ages were assessed: at 77 days, early weaning (EW) or at 147 days, conventional weaning (CW). The heifers were born in 2004 (66) and 2005 (55). After weaning, heifers were kept initially on cultivated summer pasture (Pennisetum americanum, L.) and afterward on cultivated winter/spring pasture (Avena strigosa Schreb plus Lolium multiflorum Lam.). Live weight (LW), body condition (BC) and mean live weight gain (ADG) were evaluated during the mating period. Early weaning did not cause significant difference in weight at the beginning and end of the mating period. The heifers born in 2005 showed lower live weight during the mating than those born in 2004. The year influenced the body condition at the beginning and end of the mating that was, respectively, 4.16 and 4.29 points for heifers born in 2004, and 3.57 and 3.38 points for the ones born in 2005. Pregnancy rate was not affected by the heifer weaning age (55.5 and 70.7% for EW and CW heifers, respectively), nor by year (68.6 and 57.6% for heifers born in 2004 and 2005, respectively). Heifers that became pregnant had greater reproductive performance during the growing phase and mating period than those with negative diagnosis. The reproductive performance of the heifers was positively correlated with live weight and body condition at the beginning and end of the mating period. Early weaning did not affect the heifer reproductive performance at 13/15 months old.

Avaliou-se o efeito da suplementação pré-acasalamento no desempenho reprodutivo de novilhas de corte aos 13/15 meses de idade. Foram utilizadas 89 novilhas com média de 12 meses de idade e peso corporal (PC) médio inicial de 242 kg, provenientes de três rebanhos (novilhas Aberdeen Angus das Fazendas Santa Cecília e Capitão Rodrigo e novilhas mestiças Aberdeen Angus) submetidas a regime alimentar exclusivamente em pastejo ou com suplementação a pasto com grão de milho moído. As novilhas foram agrupadas dentro dos regimes alimentares considerando o peso inicial e o rebanho. O suplemento foi fornecido diariamente na proporção de 0,7% do peso corporal por 29 dias em pastagem de aveia (Avena strigosa Schreb) e azevém (Lolium multiflorum Lam) e 19 dias em pastagem natural. O pastejo foi contínuo com taxa de lotação variável. As variáveis analisadas foram: peso corporal, condição corporal, ganho de peso médio diário, ganho de condição corporal, porcentagem de novilhas púberes, taxa de prenhez e ordem de concepção. Não houve interação regimes alimentares ×rebanhos. Durante o pré-acasalamento, o maior ganho médio diário das novilhas sob suplementação foi maior (0,800 kg) que o daquelas sem suplementação (0,658 kg). No período reprodutivo, as novilhas perderam peso, média de -0,104 kg/dia. O peso corporal e a condição corporal não diferiram ao início do período reprodutivo, média de 277 kg e 3,6 pontos, respectivamente. As novilhas sob suplementação apresentaram maior PNP (por extenso) (78%) e maior taxa de prenhez (47%). Houve interação rebanho ×período para peso corporal. A variação no peso vivo foi quadrática entre os três rebanhos. O peso corporal das novilhas mestiças foi sempre superior ao das Aberdeen Angus do rebanho Santa Cecília. As novilhas Aberdeen Angus do rebanho Capitão Rodrigo tiveram maior percentagem de novilhas púberes (80%) e taxa de prenhez (48%). A suplementação energética por 48 dias pré-acasalamento proporciona maior taxa de prenhez em novilhas de corte aos 13/15 meses de idade.The effect was assessed of pre-mating supplementary feeding on the reproductive performance of 13-15 month old beef heifers. Eighty-nine heifers were used with a mean age of 12 months and mean body weight (BW) of 242 kg from three herds Aberdeen Angus heifers from the Santa Cecilia and Capitao Rodrigo ranches and crossbred Aberdeen Angus heifers) in a feeding system of only grazing pasture or supplemented heifers on pasture with milled corn grain. The supplement was offered daily at the proportion of 0.7% of the BW for 29 days on Oats (Avena strigosa Schreb) and annual Ryegrass (Lolium multiflorum Lam) cultivated pastures and 19 days on natural pasture. The grazing was continuous with variable stocking rate. The variables analyzed were: body weight, body condition, average daily live weight gain, body condition gain, percentage of pubescent heifers, pregnancy rate and conception order. There was no feeding systems ×herd interaction. During the pre-mating, the supplemented heifers had greater ADG, 0.800 kg, compared to those without supplementation, 0.658 kg. During the mating period, the heifers lost weight, mean of -0.104 kg/day. The variables body weight and body condition did not differ at the beginning of the mating period mean of 277 kg and 3.6 points, respectively. The supplemented heifers showed higher percentage of pubescent heifers (78%) and higher pregnancy rate (47%). There was herd ×period interaction for body weight. The body weight variation was quadratic for the three herds. Crossbred heifers always had greater body weight compared to the Santa Cecília Angus heifers. Capitão Rodrigo Angus heifers had higher higher percentage of pubescent heifers (80%) and PR (48%). Energy supplementation during 48 days pre-mating promoted higher pregnancy rate in 13 to 15 month old beef heifers.

Objetivou-se avaliar a influência da condição corporal ao parto sobre alguns metabólitos sanguíneos em cabras no início da lactação. As cabras (68 no total) foram distribuídas em três grupos de acordo com o escore da condição corporal (ECC) ao parto: entre 1,00 e 2,75 (animais magros); entre 2,75 e 3,50 (condição corporal intermediária); e entre 3,50 e 5,00 (animais gordos). O experimento foi realizado nos primeiros 60 dias de lactação e as coletas de sangue, após o parto e semanalmente até a oitava semana de lactação. Foram feitas análises para determinação das concentrações de ácidos graxos não-esterificados (AGNE), beta-hidroxibutirato (BHBA), glicose, colesterol total e lipoproteína de alta densidade (HDL). As concentrações plasmáticas dos metabólitos não diferiram entre os grupos. As concentrações de AGNE, nos animais dos três grupos, ao parto e nas oito primeiras semanas de lactação, foram de 658,46 e 232,90 mg/dL, respectivamente, e os valores de BHBA ao parto, de 10,31 ± 3,0 mg/dL para os animais magros; 6,88 ± 0,9 mg/dL para os intermediários; e 4,21 ± 0,8 mg/dL para os animais gordos. Os valores de glicose ao parto foram de 112,54 ± 15,4 mg/dL para os animais magros; 90,93 ± 13,5 mg/dL para os animais intermediários; e 132,47 ± 26,7 mg/dL para os animais gordos. Os valores médios de colesterol total e de HDL nas oito primeiras semanas pós-parto foram de 109,01 ± 2,5 e 54,9 ± 1,39 mg/dL para os animais magros; 83,0 ± 21,7 e 56,0 ± 1,30 mg/dL para os intermediários; e 84,3 23,9 e 54,5 ± 1,93 mg/dL para os gordos. As alterações no metabolismo energético de cabras leiteiras de média produção diminuem, independentemente da condição corporal ao parto, quando fornecida dieta de alta qualidade e com altos níveis de energia.An experiment was carried out to study the influence of the body condition score at birth on blood metabolites of goats in early lactation. Sixty-eight goats were placed in three groups according to the body condition score (BCS) at parturition: from 1.00 to 2.75 (thin animals); 2.75 and 3.50 (intermediate body condition) and from 3.50 to 5.00 (fat animals). The experimental was carried out in the first sixty days of lactation and blood sampling started after parturition at weekly intervals up to the eighth week of lactation. Analyses were made of the non-esterified fat acids (NEFA), beta-hydroxibutirate (BHBA), glucose, total cholesterol and high density lipoprotein (HDL). The plasma concentrations of the metabolites did not differ among the groups. The NEFA concentrations in the animals in the three groups at birth and in the first eight weeks of lactation were 658.46 and 232.90 mg/dL, respectively and the values of BHBA at birth were 10.31 ± 3.0 mg/dL for the thin animals, 6.88 ± 0.9 mg/dL for the intermediate animals and 4.21 ± 0.8 mg/dL for the fat animals. The glucose values at birth were 112.54 ± 15.4 mg/dL for the thin animals, 90.93 ± 13.5 mg/dL for the intermediate animals and 132.47 ± 26.7 mg/dL for the fat animals. The average of total cholesterol and HDL in the first eight weeks after birth were 109.01 ± 2.5; and 54.9 ± 1.39 mg/dL for the thin animals, 83.0 ± 21.7 and 56.0 ± 1.30 mg/dL for the intermediate animals and 84.3 ± 23.9 and 54.5 ± 1.93 mg/dL for the fat animals. The changes in the energy metabolism of dairy goats with medium production decreased, regardless of the body condition at birth, when supplied with high quality feed with high energy levels.

Objetivou-se avaliar sistemas de alimentação para 70 novilhas de corte do início da gestação, aos 13/15 meses de idade, até o final do segundo período reprodutivo como vacas primíparas, aos 22/24 meses de idade. O delineamento experimental foi inteiramente casualizado com parcelas subdivididas no tempo considerando os animais como repetições. O peso vivo médio inicial foi de 282 kg e a condição corporal inicial de 3,2. Os sistemas de alimentação avaliados foram estabelecidos visando maior ganho de peso em pastagem cultivada na fase inicial (PCIG) ou final (PCFG) da gestação: PCIG - novilhas em pastagem de milheto (Pennisetum americanum, L.) durante a fase inicial da gestação e em pastagem natural no pré-parto; PCFG - novilhas em pastagem natural durante a fase inicial da gestação e em pastagem de aveia-preta (Avena strigosa Schreb) e azevém (Lolium multiflorum Lam) no pré-parto. Na fase inicial da gestação, o ganho de peso médio diário (GMD) de 0,424 kg das PCIG foi superior ao de 0,245 kg das PCFG. No pré-parto, as novilhas do sistema PCIG perderam peso, 0,303 kg/dia e condição corporal 0,77 ponto, enquanto as PCFG ganharam 0,901 kg/dia de PV e 0,37 ponto de CC. O peso vivo de 323 kg e a condição corporal de 3,3 pontos das novilhas do sistema PCFG pós-parto foram superiores aos das novilhas do sistema PCIG, de 274 kg e 2,6 pontos, respectivamente. As novilhas do sistema PCFG pariram bezerros 4 kg mais pesados e, ao início do período reprodutivo, apresentaram a mais 35 kg e 0,6 ponto de condição corporal. A taxa de prenhez de 85% das PCFG foi superior à de 53% das PCIG. As vacas prenhes foram as com maior condição corporal ao parto e ao início do segundo período reprodutivo, apresentaram maior intervalo do parto ao acasalamento e pariram bezerros mais pesados.The objective of this work was to evaluate the feed systems for 70 primiparous beef heifers from the initial gestation period at the age of 13/15 months to the end of the second reproductive period as primiparous cows at 22/24 months of age. The experimental design was fully random with plots subdivided in time considering animals as replicates. The initial mean live weigh was 282 kg and the initial mean body condition was 3.2. The feeding systems were proposed to obtain higher live weight gain at initial (PCIG) or final (PCFG) gestation period: PCIG - pregnant heifers on pearl millet pasture (Pennisetum americanum, L.) during the initial gestation period and on natural pasture at pre-calving period; PCFG - pregnant heifers on natural pasture during the initial gestation period and on oat (Avena strigosa Schreb) and annual ryegrass (Lolium multiflorum Lam) pasture at pre-calving period. At initial gestation period, the mean live weight gain of 0.424 kg of PCIG heifers was higher than 0.245 kg of PCFG heifers. In the pre-calving period, PCIG heifers lost weight, 0.303 kg/day and presented BC of 0.77, while PCFG heifers gained 0.901 kg/day and presented BC of 0.37. The weight of 323 kg and body condition of 3.3 of post-calving PCFG heifers were higher than 274 kg and BC of 2.6 of PCIG heifers, respectively. PCFG heifers had calves 4 kg heavier. In the beginning of the second reproduction period, PCFG cows were 35 kg heavier and presented BC of 0.60. The pregnancy rate of 85% of PCFG heifers was higher than 53% of PCIG heifers. Pregnant cows had the highest body condition rate at calving and at the beginning of the second reproduction period, presented higher calving and mating interval and heavier calves.

Objective. Evaluate the relationship between body weight, body condition and milk production in response to supplementation with whole cotton. Materials and methods. Two experimental treatments were applied to 13 cows using a randomized design: G1 (n=7), cows supplemented with 2 kg of cotton seed, and G2 (n=6), no supplemental seed. Results were analyzed using Spearman correlations. Results. There was a positive correlation between body weight and body condition (p0,05) in the supplemented cows, there was positive correlation (p0,05). Conclusions. The supplementation with cotton seed had important positive relationship among body weight, body condition, and milk production in cows of first birth managed under pasturing conditions.

O trabalho foi realizado para avaliar o desenvolvimento de 32 novilhas primíparas gestantes Aberdeen Angus e mestiças Angus recriadas e acasaladas dos 13 aos 15 meses de idade. O experimento teve início no diagnóstico de gestação pela técnica de ultra-sonografia, realizado 28 dias após o término do período reprodutivo. O peso vivo (PV) inicial médio foi de 288 kg e a condição corporal (CC) inicial média de 3,2 pontos. Nesta ocasião, as novilhas foram distribuídas uniformemente por grupo genético, peso e ordem de concepção em dois sistemas de pastejo. Os sistemas de pastejo foram: PMI - novilhas prenhes mantidas na fase inicial de gestação em pastagem de milheto (Pennisetum americanum, L.); PNA - novilhas prenhes mantidas na fase inicial de gestação em pastagem natural. O pastejo em milheto foi mantido por 67 dias. Ao fim dos tratamentos, as novilhas foram manejadas em grupo único: no pré-parto em pastagem natural, no pós-parto em pastagem de azevém (Lolium multiflorum, Lam) e no segundo período reprodutivo em pastagem natural. Na fase inicial da gestação, o ganho médio diário (GMD), de 0,899 kg, e o ganho de condição corporal (GCC), de 0,34 pontos das PMI, foram superiores ao GMD de 0,377 kg e à perda de -0,15 de CC das PNA. As novilhas PMI tiveram peso vivo pós-parto (PVP) e condição corporal pós-parto (CCP) de 301 kg e de 2,9 pontos, valores superiores aos das PNA, de 267 kg e 2,7 pontos, respectivamente. As taxas de parição, distocia, natalidade e desmame não diferiram entre os tratamentos alimentares. As novilhas PMI chegaram ao início do segundo período reprodutivo com peso (31 kg a mais) e condição corporal (0,30 ponto a mais) superiores. A taxa de prenhez e as estimativas de eficiência produtiva ao parto (EPVP) e ao desmame dos bezerros aos 100 dias de idade (EPVD) não foram alteradas pelo tratamento alimentar. A TP média foi de 77%, a EPVP média de 30,3 e a EPVD de 28,1 kg de bezerro desmamado/100 kg de vaca.This experiment was carried out to evaluate the development of 32 primiparous beef heifers Aberdeen Angus and Angus crossbred raised and mating from 13 to the 15 months of age. The experiment had beginning in the pregnancy diagnosis of using ultra-sound technique, realized at 28 days after the ending of the reproductive period. The initial average weight and body condition (BC) was 288 kg LW and 3.2 points, respectively. In this occasion, the beef heifers were uniformly distributed by genetic group, LW and conception order in two grazing systems. Grazing systems were: PMI - pregnant beef heifers maintained in the initial pregnancy period on pearl millet pasture (Pennisetum americanum, L.); PNA - pregnant heifers maintained in the initial pregnancy period on natural pasture. Grazed period was 67 days in pearl millet pasture. At end of the treatments the beef heifers were maintained as a unique group: on natural pasture at pre calving period, on annual ryegrass (Lolium multiflorum, Lam) pasture at post calving period and on natural pasture at second reproductive period. In the initial pregnancy phase, the average daily gain (ADG) of 0.899 kg and body condition gain (BCG), 0.34 points of the PMI heifers were higher then the ADG of 0.377 kg and BC lost of -0.15 for PNA heifers. The PMI beef heifers had post calving live weight (PCW) and post calving body condition of 301 kg and 2.9 points, respectively, higher values than of PNA beef heifers, 267 kg and 2.7 points. Calving, dystocia, birth and weaning rates were not different between the feeding treatment. The PMI beef heifers were 31 kg heaviest and with more 0.30 point of BC at initial second reproductive period. The pregnancy rate (PR) and estimations of calving productive efficiency (CPEE) and weaning productive efficiency at 100 days of age (WPEE) were not different between feeding treatments. Mean PR was 77%. Mean CPEE was 30.3 and WPEE 28.1 kg of weaning calf/100 kg of cow.

Foram avaliados nesta pesquisa o desenvolvimento a partir da desmama e o desempenho reprodutivo aos 13/15 meses de idade de 56 bezerras de corte Hereford e 52 Braford, com médias de peso corporal de 126 kg, de escore de condição corporal de 2,5 pontos e seis meses de idade. Os animais foram mantidos em pastagem nativa por 45 dias e, após este período, distribuídos em três sistemas alimentares (SA) por um período de 80 dias (1/6/2001 a 20/8/2001): CN+FA - suplementação em pastagem nativa (CN) com farelo de arroz desengordurado (FA); SB+FA - confinamento a céu aberto com silagem de sorgo de baixa qualidade (SB) e FA; SS+RC - confinamento a céu aberto com silagem de sorgo de qualidade superior e ração comercial (RC). Após o término dos SA, os animais permaneceram, em lote único, em pastagem de azevém (Lolium multiflorum Lam) até final de novembro e em pastagem nativa durante o período de acasalamento. Foram avaliados peso corporal (PC), escore de condição corporal (ECC), ganho de peso médio diário (GMD) e taxa de prenhez (TP). Durante os SA, o GMD das novilhas SS+RC (0,480 kg) foi superior aos demais e das SB+FA (0,252 kg), superior às CN+FA (0,174 kg). Na pastagem de azevém, os ganhos foram semelhantes (0,436 kg/dia), assim como no período de acasalamento (0,519 kg/dia). No período de acasalamento, as novilhas SS+RC foram mais pesadas e tiveram maior ECC em relação à do CN+FA. A TP média foi de 17%, sem diferenças entre os SA. As novilhas Braford apresentaram maior PV e CC ao acasalamento e maior TP que as Hereford. As novilhas prenhes foram as mais pesadas e de maior ECC à desmama, ao início e fim dos SA e do acasalamento, as mais velhas e com maiores GMD no período avaliado.The objective of this work was to evaluate the development post weaning and the reproductive performance at 13/15 months old of 56 Hereford and 52 Braford female calves, with average body weight of 126 kg, body condition score of 2.5 and six months old. The animals were kept in natural pasture (CN) during 45 days and after this period, allotted to three feeding systems (SA) for a period of 80 days (06/01/2001 to 08/20/2001): CN + FA - supplementation of CN with defatted rice bran (FA); SB + FA - open sky feedlot with low quality sorghum silage (SB) and FA; SS + RC - open sky feedlot with higher quality sorghum silage (SS) and commercial concentrate (RC). After the end of SA, the animals were kept, as a unique group, on ryegrass pasture (Lolium multiflorum Lam) until end of November and on natural pasture during the mating period. Body weight (BW), body condition score (BCS), average weight gain (AWG) and pregnancy rate (PR) were evaluated. During the SA, the AWG of the SS + RC (0.480 kg) was higher than the other systems, and of the SB + FA (0.252 kg) higher than CN + FA (0.174 kg). On ryegrass pasture, AWG were similar (0.436 kg), as well as during the mating period (0.519 kg). In the mating period, the heifers SS + RC were heavier and had higher BCS than CN + FA system. Mean pregnancy rate was 17%, without differences between SA. Braford heifers had higher BW and BCS at mating and higher PR than Hereford. The pregnant heifers were heavier and had better BCS at weaning, at beginning and end of the SA and mating time, the oldest ones and with higher AWG during the experiment than the non pregnant.

Os efeitos do livre acesso ao creep-feeding sobre os desempenhos produtivo e reprodutivo de vacas primíparas mantidas em pastagem nativa melhorada de azevém (Lolium multiflorum Lam.), trevo branco (Trifolium repens Lam.) e cornichão (Lotus corniculatus Lam. cv. São Gabriel) foram avaliados nesta pesquisa. O delineamento experimental foi o inteiramente casualizado composto por quatro tratamentos segundo esquema fatorial 2 x 2 (dois sexos: vacas amamentando bezerros ou bezerras; dois sistemas de alimentação: vacas amamentando bezerros (as) com ou sem acesso a creep-feeding), totalizando 16 unidades experimentais. As vacas primíparas do sistema com creep-feeding apresentaram peso corporal e escore de condição corporal, no final do experimento, mais altos que as do sistema sem creep-feeding (412 kg e 3,94 vs. 399 kg e 3,77, respectivamente). Vacas do sistema com creep-feeding tiveram ganho de peso médio diário mais elevados que o de vacas com bezerros não-suplementados (0,549 vs. 0,449 kg/dia). O creep-feeding e o sexo dos animais não influenciaram a taxa de prenhez das vacas primíparas.The research evaluated the effects of the creep-feeding on the productive and reproductive performance of the primiparous cows, maintained on improved natural pasture with ryegrass (Lolium multiflorum Lam.), white clover (Trifolium repens Lam.) and cornichão (Lotus corniculatus Lam. cv. São Gabriel). A completely randomized experimental design composed by four treatments according to 2 x 2 factorial arrangement (two sex: cows suckling male or female calves; two systems of feeding: cows suckling male or female with or without access creep-feeding, totalizing 16 experimental units. The primiparous cows of the creep-feeding system showed body weight and corporal condition, in the end of the experiment, higher in relation to the ones without creep-feeding system (412 kg and 3.94 versus 399 kg and 3.77, respectively). Cows in the creep-feeding system showed average daily weight gain higher than the cows with calves without access to creep-feeding (0.549 vs. 0.449 kg/day). Creep-feeding and the sex of calves did not influence the pregnancy rate of primiparous cows.

Objetivou-se avaliar o efeito da suplementação no pré-parto e da idade à desmama sobre o desempenho de cordeiros terminados em confinamento. Foram utilizadas 44 matrizes mestiças Ile de France × Bergamácia acasaladas com cordeiro Ile de France mantidas em pastagem de Panicum maximum cv. Tanzânia, em sistema de pastejo rotacionado, até 30 dias antes do parto, quando foram separadas em dois grupos. No pré-parto, apenas o primeiro grupo (SUPL) recebeu suplementação (1% peso vivo) com dieta balanceada. Após o parto, ambos os grupos, com (SUPL) e sem suplementação (NS), receberam suplementação. Por sorteio, metade dos cordeiros de cada grupo foi desmamada aos 45 dias e a outra metade, aos 60 dias de idade. Após a desmama, os cordeiros foram mantidos em confinamento com dieta balanceada e abatidos aos 30 kg de PV, após jejum de sólidos de 16 horas. O peso e a condição corporal ao parto das ovelhas diferiram entre os grupos, o que não ocorreu ao desmame. Os peso ao nascimento e ao desmame, o ganho de peso do nascimento ao desmame e do desmame ao abate, o período em confinamento e a idade ao abate não diferiram entre os cordeiros. O peso ao desmame e o ganho de peso do desmame ao abate foram influenciados pela idade à desmama (os cordeiros apresentaram 0,20 kg aos 45 dias e 0,15 kg aos 60 dias de idade). A suplementação proporcionou melhor condição corporal às ovelhas e a desmama aos 45 dias promoveu melhor desempenho aos cordeiros.The objective of this trial was to evaluate the effect of ewe pre-partum supplementation and weaning age on performance of lambs. Forth-four Ile de France x Bergamasca ewes that were mated with Ile de France rams were used in this trial. Animals were maintained in a rotational grazing system of Panicum maximum (cv. Tanzânia) pasture until 30 days before parturition. Ewes were then divided in two groups: supplemented (SUPL) and not-supplemented (NS); animals on the SUPL group were supplemented (1% of body weight [BW]) with a balanced diet according to NRC (1985) requirements. After parturition, both groups were supplemented. Half of lambs from the SUPL and NS groups were weaned at 45 days of age and the other half at 60 days of age. After weaning lambs were feedlot fed with a diet balanced according to NRC (1985) model. Lambs were slaughtered when they reached 30 kg of BW after 16 hours of solids fasting. Both BW and body condition score of ewes at parturition differed between SUPL and NS groups while the same was not observed at weaning. Birth weight, weaning weight, weight gain from birth to weaning and from weaning to slaughter, days in feedlot, and slaughter age all were not different in lambs born from ewes of the SUPL or NS groups. However, significant differences were observed for weaning weight and weight gain from weaning to slaughter between groups of animals weaned at 45 or 60 days of age.

Avaliou-se o desenvolvimento de bezerras de corte de diferentes rebanhos submetidas no pós-desmame a níveis de suplementação em pastagem nativa no outono e em pastejo em aveia preta (Avena strigosa Schreb) e azevém (Lolium multiflorum Lam) durante o inverno, em um período total de 135 dias. Foram utilizadas 118 bezerras com sete meses de idade em maio de 2003, provenientes de três rebanhos distintos: R1 e R2 - bezerras Aberdeen Angus; RG - bezerras mestiças Aberdeen Angus. Os níveis de suplementação foram 0,7; 1,0 e 1,3% do PV. Na pastagem cultivada os animais ficaram em grupo único. Foram avaliados o PV, a condição corporal (CC), o ganho de peso médio diário (GMD), o ganho de condição corporal (GCC) e o crescimento relativo (CR). Não houve interação níveis de suplementação ´ rebanho. Durante o outono em pastagem nativa, as bezerras suplementadas com 1,3% do PV tiveram maior GMD (0,405 kg) em relação às de 0,7% do PV (0,300 kg). Na pastagem cultivada, o GMD não diferiu entre os níveis de suplementação do outono, com média de 0,820 kg. Considerando os diferentes rebanhos, os animais RG tiveram sempre PV e CC superiores aos demais. As bezerras do R1, com menor PV e CC inicial, igualaram-se às do R2 ao final do período hibernal. As bezerras R1 tiveram maior CR (77,1% do PV e 32,4% da CC) em relação as do R2 e RG, as quais tiveram em média 57,1% do PV e 14,7% da CC. As variáveis PV e CC iniciais foram altamente correlacionadas (r=0,811), entretanto, não tiveram correlação com GMD durante a recria. O PV e a CC final foram determinados pelo PV inicial e pelo GMD durante a recria. As bezerras mais pesadas à desmama não foram necessariamente as mais pesadas aos 12/13 meses de idade.This trial evaluated the effects of different levels of supplementation on the growth of weaned female beef calves grazing native pasture during the fall. Development of these same animals grazing pastures of black oat (Avena strigosa Schreb) and annual ryegrass (Lolium multiflorum Lam) during the winter were also investigated. One hundred-eighteen female calves averaging seven months of age from three distinct herds: H1 and H2 (Aberdeen Angus animals) and H3 (crossbred Aberdeen Angus animals) were used. Calves grazing the native pasture were supplemented with a commercial concentrate as follows: 0.7, 1.0 or 1.3% of body weight (BW). During the winter, animals were moved to pastures of black oat and annual ryegrass and were all maintained in the same group. The following measurements were taken: BW, body condition (BC), average daily gain (ADG), body condition gain (BCG), and relative growth (RG). No significant supplementation levels ´ herd interactions were detected. Animals grazing native pasture supplemented with 1.3% BW as concentrate had greater ADG (0.405 kg) than those supplemented with 0.7% BW (0.300 kg). The ADG of animals grazing black oat and annual ryegrass did not differ and averaged 0.820 kg. Within the three herds, animals from H3 had greater BW and BC than those from H1 and H2. Calves from H1 with lower initial BW and BC showed compensatory growth and had similar BW and BC compared to H2 calves at the end of the winter period. H1 calves had higher RG (77.1% of BW and 32.4% of BC) than H2 and H3 calves, which averaged 57.1% of BW and 14.7% of BC. Initial BW and BC were highly correlated (r=0.811) but both were not correlated with ADG during rearing. The final BW and BC were affected by initial BW and ADG during rearing. Calves with the greatest BW at weaning were not always the heaviest animals at one year of age.

Foi desenvolvido um experimento para identificar os efeitos que influenciam a taxa de prenhez de 117 vacas de corte Nelore x Hereford aos 2 e 20 anos de idade e com diferentes frações gênicas de Nelore (25,0; 37,5; 50,0 e 100,0%), paridas no período de 11/08/03 a 23/12/03 e acasaladas, por monta natural, entre 10/12/03 e 12/03/04. Foram avaliados os efeitos dos fatores data juliana de parto (DJ), peso ao nascer (PN), sexo do bezerro (S) do parto anterior, ordem de parto (OP), altura de garupa (H), peso ao início do acasalamento (PI), escore de condição corporal ao início do acasalamento (ECCI), ganho diário médio de peso durante o acasalamento (GDA), fração gênica de Nelore (FGN) e peso ao desmame ajustado (PAJ205) do parto anterior sobre a probabilidade de prenhez e de concepção. Os dados foram submetidos à análise de regressão logística, por meio do procedimento LOGISTIC do pacote computacional SAS, para identificar os efeitos de cada variável. A média da taxa de prenhez foi de 43,2%. A probabilidade de prenhez e as chances de concepção foram explicadas pelas variações de DJ, PI, ECCI e GDA. A mudança na chance de prenhez para cada acréscimo na variável regressora foi estimada com base na estatística da razão entre chances (odds ratio), determinada por OR = exp(b k), considerando que chance é a razão entre a probabilidade de o evento ocorrer e a de não ocorrer. Não foram observados efeitos significativos de PN, S, OP, H, FGN e PAJ205. Portanto, para aumentar as taxas de prenhez de vacas de corte, são necessárias melhorias no escore de condição corporal (ECC) no início do acasalamento e no ganho de peso (GP) durante a estação de monta, ambos decorrentes de adequada nutrição pré e pós-parto.This experiment was conducted to evaluate factors affecting pregnancy rate of 117 crossbred Nelore x Hereford beef cows with age varying from 2 to 20 years, different gene proportion from Nellore breed (25.0, 37.5, 50.0, and 100.0%), calved between 08/11/03 and 12/23/03 and bred by natural service, between 12/10/03 and 03/12/04. The effects of July calving date (JCD), birth weight (BW) and calf sex (S) from previous calving, parity order (PO), hip height (H), weight (WM) and body condition score at the beginning of the mating season (BCS), daily gain during the mating season (DGM), gene proportion from Nellore (GPN) and calf 205-d weight (WW205) from previous calving were all investigated on the probabilities of pregnancy and conception. Data were analyzed by Logistic Regression using SAS to identify the effects of each variable. The average pregnancy rate was 43.2%. The probability of pregnancy and conception were affected by changes on JCD, WM, BCS and DGM. The pregnancy odd changing to each increase on the variable were based on the odds ratio estimative by OR = exp (b k), considering that odd is ratio between the probability of the event occur and not occur. No significant effects of BW, S, PO, H, GFN and WW205 were observed. Pregnancy rate in beef cows can be increased by improving body condition score at the beginning of breeding season and weight gain during the breeding season. Both can be achieved by pre and postpartum nutritional management.

Avaliou-se, durante quatro estações de monta (1/11 a 31/1 do ano seguinte), o efeito da ordem de parto (OP) e da condição corporal (CC), segundo escala de 1 (magra) a 5 (gorda), sobre o desempenho reprodutivo de 468 fêmeas Nelore, sendo 391 vacas multíparas e 77 primíparas, em pastagem de Brachiaria decumbens Stapf, na região dos Cerrados, no Brasil Central. A OP teve efeito quadrático na taxa de prenhez (TP). Vacas OP1 apresentaram TP de 69%, OP5 a OP8 de 90%, com declínio gradual até 80% de prenhez na OP12. A CC à desmama afetou a TP. Pela análise de regressão, vacas OP1 com CC 2,0 e 3,5 tiveram TP de 52,7 e 82,5%, respectivamente. Observou-se TP DE 96% em vacas com OP4 e OP8 e CC 3,5. A TP de vacas OP1 com parição tardia foi de 37,7%, mas, independentemente da OP, vacas que pariram no início da temporada tiveram TP superiores a 80%. Vacas OP1 pariram 350,12 dias após o início da monta, enquanto aquelas com OP superiores, necessitaram de 328,32 dias. Vacas OP1 apresentaram o mais longo intervalo de partos (IP), com 392,10 dias, ao passo que o IP das OP5 a OP9 foi de 365 dias. O IP foi afetado pelo ano, pela OP, pelo número de dias necessários para parir na estação de parição e pela variação de peso na estação de cobrição. O peso vivo e a CC das vacas à desmama foram afetados pela OP e pelo ano. O peso à desmama (PD) do bezerro aumentou da OP1 até a OP4/OP5, de modo que as vacas OP1 proporcionaram PD de 159 kg e a média dos PD das OP foi de 169 kg. Altos índices produtivos e reprodutivos são obtidos entre OP3 e OP8 com CC acima de 3,0 e 3,5 em vacas Nelore multíparas e prímaparas, respectivamente.The objective of this trial was to evaluate the effects of calving order (CO) and body condition score (BCS), scale 1(thin) to 5 (fat), on reproductive performance of 468 Nellore cows (391 multiparous and 77 primiparous) grazing Brachiaria decumbens Stapf at Brazilian Central West (Cerrados region) during four breeding seasons (from 11/1 to 1/31 of the following year). Calving order quadratically affected pregnancy rate (PR) in this trial; PR of CO1 cows was 69% while that of cows from CO5 to CO8 was 90% followed by a gradual decline until 80% PR in C012 cows. Body condition score at weaning also affected PR. For instance, CO1 cows with BCS of 2.0 and 3.5 had 52.7 and 82.5% of PR, respectively. Cows from CO4 to CO8 and BCS of 3.5 showed 96% of PR. CO1 cows that calved late in the season had 37.7% of PR but independent of CO, cows that calved earlier in the calving season had PR greater than 80%. CO1 cows calved 350.12 days after the start of the mating season while multiparous cows calved earlier (328.32 days). CO1 had the longest calving interval (CI) averaging 392.10 days whereas that from CO5 to CO9 cows averaged 365 days. Calving interval was affected by year, CO, number of days spent to calve in the calving season, and body weight change in the mating season. In addition, cows body weight (BWW) and BC at weaning (BCW) were both affected by CO and year. Body weight of calves at weaning increased from CO1 to CO4/CO5 averaging 159 kg for calves from CO1 cows and 169 kg when all CO levels were included. High production and reproductive performance are obtained from CO3 to CO8 and BCS above 3.0 and 3.5 for multiparous and primiparous Nellore cows, respectively.

O efeito de duas disponibilidades de forragem (DF), 1.200 e 1.500 kg/ha de matéria seca (MS), e do uso da suplementação energética no desempenho de novilhas de corte em pastagem de aveia preta (Avena strigosa Schreb) mais azevém (Lolium multiflorum Lam) foi avaliado. As novilhas foram alocadas em quatro combinações: DFBN - disponibilidade de forragem (DF) baixa, sem suplementação; DFAN - DF alta, sem suplementação; DFBS - DF baixa + suplementação; DFAS - DF alta + suplementação. O suplemento utilizado foi grão de sorgo moído, na proporção de 0,7% do peso vivo (PV) por dia. O método de pastejo foi contínuo, com lotação variável, utilizando-se três repetições de área por combinação. As variáveis estudadas foram: oferta de forragem (OF), ganho de peso médio diário (GMD), condição corporal (CC), peso vivo dos animais aos 12 meses de idade, proteína bruta e digestibilidade in vitro da matéria orgânica da forragem aparentemente consumida. A OF com disponibilidade de forragem alta (DFA) foi superior àquela com disponibilidade de forragem baixa (DFB), com valores de 11 e 8 kg de MS/100 kg de PV, respectivamente. A suplementação afetou o GMD e CC. O GMD foi, em média, de 0,778 e 0,559 kg/animal/dia para as novilhas suplementadas e exclusivamente sob pastejo, respectivamente. A CC elevou linearmente durante o período de pastejo. O desempenho das novilhas recebendo suplementação melhorou 0,9 pontos (R² = 96%) e o das exclusivamente em pastagem, 0,4 pontos na CC (R² = 74%), com ganhos de 115 e 187 kg/ponto adicional na CC, respectivamente. A redução na massa de forragem de 1.500 para 1.200 kg/ha de MS não alterou o desempenho de novilhas. Animais suplementados apresentaram maior ganho de peso e melhor condição corporal que os exclusivamente em pastagem.The effect of two herbage masses (HM) (1,200 or 1,500 kg/ha of dry matter - DM) and use of energy supplementation on performance of beef heifers grazing oat (Avena strigosa Schreb) plus annual ryegrass (Lolium multiflorum Lam) was evaluated. The heifers were assigned to the following treatments: LHMNS - low herbage mass, no supplementation; HHMNS - high herbage mass, no supplementation; LHMS - low herbage mass + supplementation;HHMS - high herbage mass + supplementation. The supplement utilized was ground sorghum grain, at the level of 0.7% of body weight (BW) per day. The grazing method was continuous with variable stocking rate; there were three replications per treatment combination. The variables evaluated were: forage allowance (FA), average daily weight gain (ADG), body condition (BC), body weight of animals at 12 months of age (BLW), crude protein and 'in vitro' digestibility of hand plucked herbage samples. The FA in HHM was greater than in LHM treatment, with values of 11 and 8 kg of DM/100 kg of BW, respectively. Supplementation affected ADG and BC. The ADG were 0.778 and 0.559 kg/animal/day for supplemented and not supplemented heifers, respectively. The BC increased linearly during the grazing period. Supplemented heifers body condition increased by 0.9 points (R2=96%) and those exclusively on pasture by 0.4 points (R2=74%), with LW gains of 115 and 187 kg for each additional point of BC. Decrease of forage mass from 1.500 to 1.200 kg/ha DM did not affect heifer performance. Supplemented animals had higher body weight gain and body condition than animals exclusively on pasture.

A produtividade de vacas Nelore foi estimada durante quatro anos em pastagem de Brachiaria decumbens Stapf, com correção inicial da acidez e da fertilidade do solo e livre acesso a uma mistura mineral. Foram determinadas as taxas de prenhez (TP), de natalidade (TN) e de desmama (TD), o peso à desmama dos bezerros (PD), a produção de quilos de bezerros por vaca (P) e a eficiência de produção de bezerro por vaca (E) e por área (EA), bem como o peso e a condição corporal (CC) das vacas antes da estação de parição (PAP e CCP), durante o acasalamento (PMA e CCM) e à desmama (PVD e CCD). A TP média foi de 87,5%, enquanto a TN e a TD foram de 81,7 e 77,2%, respectivamente, considerando-se todas as vacas expostas a touros. O PD médio foi de 170 ± 21,89 kg, com a média de 202 ± 16,48 dias de idade à desmama. A ordem de parto (OP) influenciou o peso dos bezerros à desmama. Bezerros mais pesados foram produzidos pelas vacas entre a OP3 e a OP9. A P e E por vaca exposta a touro foram de 130 e 32,19 kg, respectivamente, e a EA foi de 192 kg/ha. Nos períodos PAP, PMA e PVD, os pesos vivos foram de 471 ± 19,67 kg, 405 ± 21,48 kg, 410 ± 9,35 kg e as condições corporais 4,45 ± 0,30, 3,32 ± 0,44, 3,54 ± 0,19, respectivamente. A correlação entre peso vivo e condição corporal foi de 0,66. Vacas Nelore, em pastagem de Brachiaria decumbens Stapf com correção inicial da acidez e fertilidade do solo, apresentaram altos índices reprodutivos e produtivos. Vacas em ordens de parto intermediárias foram mais produtivas que as vacas no início e no final da vida reprodutiva.The productivity of Nelore cows on Brachiaria decumbens Stapf pasture was measured during four years, in a soil initially improved with limestone and fertilizer and with free access to a mineral mixture. Pregnancy rate (PR), calving rate (CR), weaning rate (WR), calves weaning body weight (BWC), productivity (P = kg of calf/cow) and efficiency (E= P/100 kg of cow) per cow, productivity per area (AP = calves kg/ha), as well as cow body weight and body condition before the calving season (CLW and CBC), at the middle of the mating season (MLW and MBC) and at weaning (WLW and WBC) were evaluated. Mean PR, CR and WR of 87.5, 81.7 and 77.2%, respectively, were observed. Mean LWC of 170 ± 21.89 kg and mean weaning age of 202 ± 16.48 days were observed. Significant effect of calving order (CO) on LWC was detected. Cows between CO3 and CO9 weaned the heaviest calves. Values of 130 kg and 32.19 kg were observed for P and E, respectively, with AP of 192 kg/ha. The CLW and CBC, MLW and MBC, and WLW and WBC were of 471 + 19.67 kg and 4.45 + 0.30; 405 + 21.48 kg and 3.32 + 0.44; 410 + 9.35 and 3.54 + 0.19, respectively. The correlation between body weight and body condition was of 0.66. Nelore cows maintained on a tropical pastures of Brachiaria decumbens Stapf, in an initial fertilized soil, had high reproduction level and productivity. Cows with medium calving order had higher productivity than primiparous and older cows.