Effect of oestrous synchrony between embryo donors and recipients, embryo quality and state on the pregnancy rate in beef cattle.

This study aimed to evaluate the effect of oestrous synchrony between donors and recipients and the embryo quality on the pregnancy rate in beef cow recipients. The experiment was performed over two years at an embryo transfer (ET) centre in Southern Brazil. Ninety Aberdeen Angus cows were subjected to superovulation (SOV) protocols, resulting in the recovery of 1,048 transferable embryos. Eleven groups were formed with intervals of 6 hr, from -30 to +30 hr, with respect to recipient versus donor oestrous detection. Evaluation of embryo quality was according to the IETS guidelines. The overall pregnancy rate was 52%. Effects related to donor and recipient oestrous synchronization on pregnancy rate were observed (p = .01), ranging from 36% to 50%. The embryo quality rate affected the pregnancy rate, where Grade I resulted in 57% and Grade III in 43% of pregnancy (p < .001). The embryonic state (frozen or fresh) showed no (p > .05) effect on pregnancy rate: 53% for fresh embryos and 44% for frozen embryos. The odds ratio for explanatory variables causing pregnancy indicated that Grade III embryos had 31% less chance of conception compared to Grade I. Thus, oestrous synchrony between donor and recipient, considering ±30 hr apart, can affect the pregnancy rate along with embryo quality.

Melaleuca alternifolia nanoparticles against Candida species biofilms.

Candida infection is an important cause of morbidity and mortality on immunosuppressed patients. This growing trend has been associated with resistance to the antimicrobial therapy and the ability of microorganism to form biofilms. TTO oil is used as antimicrobial which shows antibiofilm activity against Candida species. However, it presents problems due to its poor solubility and high volatility. The present study aimed to evaluate in vitro antibiofilm activity of TTO nanoparticles against many Candida species. It was performed the characterization of the oil and nanoparticles. The levels of exopolysaccharides, proteins, and the biomass of biofilms were measured. The chromatographic profile demonstrated that the TTO oil is in accordance with ISO 4730 with major constituents of 41.9% Terpinen-4-ol, 20.1% of γ-Terpinene, 9,8% of α-Terpinene, and 6,0% of 1,8-Cineole. The TTO nanoparticles showed pH of 6.3, mean diameter of 158.2 ± 2 nm, polydispersion index of 0.213 ± 0.017, and zeta potential of -8.69 ± 0.80 mV. The addition of TTO and its nanoparticles represented a significant reduction of biofilm formed by all Candida species, as well as a reduction of proteins and exopolysaccharides levels. It was possible to visualize the reduction of biofilm in presence of TTO nanoparticles by Calcofluor White method.

Genetic progress in sunflower crop in Rio Grande do Sul State, Brazil.

The sunflower has adaptability to growing regions with different climatic and soil characteristics, showing drought tolerance and high-quality oil production. The State of Rio Grande do Sul is the third largest sunflower producer in Brazil, with research related to the sunflower breeding initiated after the decade of 1950. The aim of this study was to evaluate the genetic progress for grain yield, oil content, and oil yield of sunflower (Helianthus annuus L.) in the State of Rio Grande do Sul. Data of grain yield, oil content, and oil yield obtained from 58 sunflower cultivar yield trials in 19 municipalities in Rio Grande do Sul during the period from 2005 to 2014 were used. Genetic progress was studied according to the methodology proposed by Vencovsky and data from sunflower cultivar yield trials were used. Annual genetic progress of sunflower during the period of 10 years (2005-2014) was 132.46 kg⋅ha-1⋅year-1 for grain yield, -0.17%/year for oil content, and 48.11 kg⋅ha-1⋅year-1 for oil yield. The sunflower-breeding programs in the State of Rio Grande do Sul were efficient for the traits grain yield and oil yield and presented no efficiency for oil content.

Brazilian Pampa Biome Honey Protects Against Mortality, Locomotor Deficits and Oxidative Stress Induced by Hypoxia/Reperfusion in Adult Drosophila melanogaster.

We aimed to investigate the potential beneficial effects of the Brazilian Pampa biome honey in a Drosophila-based hypoxia model. Adult flies were reared in standard medium in the presence or absence of honey (at a final concentration of 10 % in medium). Then, control flies (4 % sucrose in medium) and honey-treated flies were submitted to hypoxia. Subsequently, flies were analyzed for mortality, neurolocomotor behavior (negative geotaxis), mitochondrial/oxidative stress parameters and expression of hypoxia/stress related genes by RT-qPCR. The HPLC analysis revealed the presence of phenolics and flavonoids in the studied honey. Caffeic acid was the major compound followed by p-coumaric acid and kaempferol. The presence of such compounds was correlated with a substantial antioxidant activity in vitro. Flies subjected to hypoxia presented marked mortality, locomotor deficits and changes in oxidative stress and mitochondrial activity parameters. Honey treatment was able to completely block mortality and locomotor phenotypes. In addition, honey was able to reverse ROS production and hypoxia-induced changes in mitochondrial complex I and II activity. Hypoxia also induced an up-regulation in mRNA expression of Sima (HIF-1), NFκß, NRF2, HOX, AKT-1, InR, dILP2, dILP5 and HSP27. Honey treatment was not able to modulate changes in the tested genes, indicating that its protective effects involve additional mechanisms other than transcriptional activity of hypoxia-driven adaptive responses in flies. Our results demonstrated, for the first time, the beneficial effects of honey against the deleterious effects of hypoxia/reperfusion processes in a complex organism.

Estimates of genetic parameters for stayability and their associations with traits of economic interest in Gir dairy cows.

The objective of the present study was to estimate genetic parameters for stayability at 60 months of age (STAY60) and its association with first lactation cumulative milk yield (P305), age at first calving (AFC), and first calving interval (FCI), in order to adopt these traits as selection criteria for longevity in Gir dairy cattle. Records for 2770 cows born between 1982 and 2008 from six herds in the Brazilian states of Minas Gerais, São Paulo, and Paraíba were analyzed. The (co)variance components were estimated by a Bayesian approach using bivariate animal models. The heritability estimates were 0.37 ± 0.09, 0.23 ± 0.04, 0.26 ± 0.06, and 0.07 ± 0.03 for STAY60, P305, AFC, and FCI, respectively. The genetic correlations of STAY60 with P305, AFC, and FCI were moderate to high, with values of 0.61 (0.17), -0.44 (0.23), and 0.88 (0.13), respectively. STAY60, P305, and AFC exhibited additive genetic variability, and these traits should be considered in selection indices. The indirect selection for longevity through the correlated responses of early-expression traits, such as milk production at first lactation, could be used to improve the ability of animals to remain in the herd.

Genetic models for breed quality and navel development scores and its associations with growth traits in beef cattle.

Estimation and prediction ability of linear and threshold models for yearling breed quality score (BQ) and navel development score at weaning (WN) and yearling (YN), considering variances, heritabilities, and rank correlations based on the breeding values predicted for bulls, were compared. Furthermore, it was determined whether BQ, WN, and YN are genetically associated with growth traits (BWG: birth to weaning weight gain, WH: weaning height, WYG: weaning to yearling weight gain, YH: yearling height) to field data of Nelore cattle. For BQ, similar heritabilities were estimated using linear (0.14 ± 0.01) and threshold (0.15 ± 0.02) models. For navel development scores, higher heritability was estimated with threshold (WN 0.22 ± 0.03; YN 0.42 ± 0.03) rather than linear (WN 0.16 ± 0.01; YN 0.29 ± 0.01) models. Rank correlations between sires breeding values predicted for visual scores with linear and threshold models ranging from 0.53 to 0.98, indicating that different sires would be selected using these models, mainly for higher selection intensities. The BQ showed little genetic variability and was not associated with WH and YH. However, low and positive genetic correlations were obtained between BQ with BWG (0.27 ± 0.02) and WYG (0.25 ± 0.02). In general, they are expected low genetic gains for BQ as correlated response to selection based on any of the growth traits studied. The WN showed higher genetic correlation with BWG (0.63 ± 0.02) and WH (0.53 ± 0.02) rather than WYG (-0.06 ± 0.02) and YH (0.26 ± 0.02), indicating that selection for increased growth at weaning (height and weight gain) should lead to longer and most pendulous navels at this age. Weak genetic correlations were obtained between yearling navel and growth traits.

Associations between single nucleotide polymorphisms and carcass traits in Nellore cattle using high-density panels.

The objective of this study was to evaluate associations between single nucleotide polymorphism (SNP) markers and carcass traits measured postmortem in Nellore cattle. Records of loin eye area (LEA) and backfat thickness (BF) from 740 males and records of hot carcass weight (HCW) from 726 males were analyzed. All of the animals were genotyped using the BovineHD BeadChip. Association analyses were performed by the restricted maximum likelihood method that considered one SNP at a time. Significant SNPs were identified on chromosomes 2 and 6 for LEA and on chromosomes 7, 1, and 2 for BF. For HCW, associations with SNPs were found on chromosomes 13, 14, and 28, in addition to genome regions that were directly related to this trait, such as the EFCAB8 and VSTM2L genes, and to bone development (RHOU). Some SNPs were located in very close proximity to genes involved in basal metabolism (BLCAP, NNAT, CTNNBL1, TGM2, and LOC100296770) and the immune system (BPI).

Genetic associations between temperament and performance traits in Nellore beef cattle.

The aim of this study was to estimate genetic associations between temperament and performance traits. Temperament was evaluated in yearling male and female Nellore cattle, using four traits: temperament score (TS), for assessing animals' reactions in a corral pen (n = 25,691); movement score (MOV), for animals' movements recorded inside the crush; crush score (CS), for animal's general reactivity inside the crush; and flight speed (FS), for the speed (in m/s) at which the animals exited the crush (n = 11,697, for the last three methods); for all the temperament traits, lower scores indicate animals with calmer temperament. Performance traits were visual scores for conformation (C), finishing precocity (P) and muscling (M) evaluated at yearlings, and average daily gain (ADG) was estimated from weaning to yearling. Bayesian inference using Gibbs sampling was applied to estimate (co)variance components and genetic and phenotypic parameters. Heritability estimates for the temperament traits ranged from 0.07 (CS) to 0.28 (FS). Genetic correlations of the temperament traits with ADG and C, P and M were negative and ranged from -0.02 to -0.31. Phenotypic correlations were negative and consistently lower than the genetic, ranging from -0.08 to -0.02. It was concluded that the temperament traits assessed had favourable genetic correlation estimates with the performance traits studied. However, indirect responses in temperament when selecting for higher ADG and visual scoring system of C, P and M, will be low.

Finishing precocity visual score and genetic associations with growth traits in Angus beef cattle.

Finishing precocity visual score selection was adopted to estimate the time from birth to reach slaughter age. This study estimated (co)variance components and genetic correlations for the finishing precocity score at weaning (WP) and yearling (YP) stages by using daily weight gain (BWG = from birth to weaning; WYG = from weaning to yearling) and speed of weight gain (BWR = from birth to weaning; WYR = from weaning to yearling) as support for a genetic evaluation program for Angus beef cattle. Genetic parameters were estimated using Bayesian inference, considering multi-trait analysis and assuming a nonlinear model for WP and YP and linear model for all other traits. Direct heritability estimates were 0.17 (WP), 0.19 (YP), 0.15 (BWG), 0.16 (WYG), 0.15 (BWR), and 0.16 (WYR). The genetic correlation between the finishing precocity score at two ages (weaning and yearling) was 0.61. Positive and moderate genetic correlations were obtained between WP and BWG (0.47) and WP and BWR (0.46). In contrast, negative and low genetic associations were estimated between WP and yearling growth traits (-0.16, WYG; -0.15, WYR). Genetic correlations between YP and other traits were positive 0.29 (BWG), 0.28 (BWR), 0.48 (WYG), and 0.47 (WYR). The selection response for the finishing precocity score at weaning and yearling ages would be low. Selection to increase WP and YP should result in favorable genetic changes in daily weight gains as a correlated response. Therefore, to obtain animals suited for beef cattle production systems, finishing precocity score and growth traits should be considered as selection criteria.

Longitudinal genetic dynamics of weaning index and implications for cow-calf production efficiency.

In beef cattle, the selection for higher weights at young ages has been questioned with the argument that this criterion may increase the adult weight of cows, resulting in higher costs. Therefore, selection criteria should be employed to increase weights at young ages with minimal impact on the adult weight of cows. Additionally, the relationship between measures of cow production efficiency and other well-established selection criteria in breeding programs remains poorly understood. The objective of this study was to longitudinally evaluate the relationship between the weaning index (WIndex) as a measure of efficiency and growth traits of the cows. Possible changes over time in WIndex due to selection applied for yearling weight (YW) were also investigated. The WIndex was proposed to maximize genetic response in the weaning weight of the calf while maintaining genetic gain in BW of the cow at zero. A random regression model was adopted to estimate correlations between WIndex, BW, hip height (HH), and body condition score (BCS) using records of Nelore cows from three lines. Genetic trends were calculated for the control line (NeC) and lines selected for greater YW (NeS and NeT). The age of 3 years was the most critical for the weaning efficiency of the cows. At this stage, young cows are still growing and wean lighter calves than their adult counterparts. The genetic correlation estimates between WIndex and BW (-0.58 to 0.04), HH (-0.05 to -0.34), and BCS (-0.51 to -0.17) were close to zero or negative. BW and HH were strongly correlated genetically across all ages (0.73-0.76). In general, HH exhibited a weak and negative genetic relationship with BCS. The genetic correlation between BW and BCS was stronger for advanced ages (0.45-0.68). In lines selected for YW, important increases in WIndex were observed. However, NeS has been selected since the 1980s until the present for YW, and thus, it showed a more pronounced trend of increasing BW and, consequently, a more modest trend of increasing WIndex compared to NeT. In contrast, WIndex exhibited a trend close to zero for NeC. In this context, monitoring HH and BCS can be useful to avoid losses in the weaning efficiency of cows. Furthermore, we suggest that one way to mitigate efficiency losses in calf production could involve stabilizing the BW of cows and increasing the weaning weight of calves using the WIndex.

Linear and Poisson models for genetic evaluation of tick resistance in cross-bred Hereford x Nellore cattle.

Cattle resistance to ticks is measured by the number of ticks infesting the animal. The model used for the genetic analysis of cattle resistance to ticks frequently requires logarithmic transformation of the observations. The objective of this study was to evaluate the predictive ability and goodness of fit of different models for the analysis of this trait in cross-bred Hereford x Nellore cattle. Three models were tested: a linear model using logarithmic transformation of the observations (MLOG); a linear model without transformation of the observations (MLIN); and a generalized linear Poisson model with residual term (MPOI). All models included the classificatory effects of contemporary group and genetic group and the covariates age of animal at the time of recording and individual heterozygosis, as well as additive genetic effects as random effects. Heritability estimates were 0.08 ± 0.02, 0.10 ± 0.02 and 0.14 ± 0.04 for MLIN, MLOG and MPOI models, respectively. The model fit quality, verified by deviance information criterion (DIC) and residual mean square, indicated fit superiority of MPOI model. The predictive ability of the models was compared by validation test in independent sample. The MPOI model was slightly superior in terms of goodness of fit and predictive ability, whereas the correlations between observed and predicted tick counts were practically the same for all models. A higher rank correlation between breeding values was observed between models MLOG and MPOI. Poisson model can be used for the selection of tick-resistant animals.

Genetic correlations between heifer subsequent rebreeding and age at first calving and growth traits in Nellore cattle by Bayesian inference.

We estimated heritability for subsequent rebreeding (SR) of heifers and genetic correlations between this trait and weaning weight (WW), weight gain from weaning to yearling (WG), age at first calving (AFC), and mature cow weight (MW), in order to evaluate whether SR could be included as selection criterion in Nellore cattle. The SR of heifers was defined by attributing a value of 1 (success) or 0 (failure) to heifers that calved or not, respectively, given that they had calved once before. Records from 127,430 Nellore animals were analyzed. Genetic parameters were estimated by Bayesian inference using a nonlinear (threshold) animal model for SR and a linear animal model for the other traits in three-trait analyses, including SR and WW in all analyses. The posterior means of heritability for SR, WW, WG, AFC, and MW were 0.18 ± 0.02, 0.21 ± 0.01, 0.30 ± 0.01, 0.21 ± 0.01, and 0.45 ± 0.04, respectively. The posterior mean estimates of genetic correlations between SR and WW, WG, AFC, and MW were -0.20 ± 0.06, 0.31 ± 0.07, -0.77 ± 0.05, and -0.15 ± 0.09, respectively. Based on these genetic correlations, selection for higher gains for WG and younger AFC should result in an increase in heifer SR rates, while long-term selection for increasing WW should promote unfavorable responses in heifer SR. The use of breeding values for heifer SR as a selection criterion of Nellore bulls could increase heifer SR rate without significant changes in MW.

Genetic correlations between mature cow weight and productive and reproductive traits in Nellore cattle.

We investigated genetic associations between mature cow weight (MW) and weaning weight (WW), yearling weight (YW), weight gain from birth to weaning (GBW), weight gain from weaning to yearling (GWY), weaning hip height (WHH), yearling hip height (YHH), scrotal circumference (SC), and age at first calving (AFC). Data from 127,104 Nellore animals born between 1993 and 2006, belonging to Agropecuária Jacarezinho Ltda., were analyzed. (Co)variance components were obtained by the restricted maximum likelihood method, applying an animal model in a multi-traits analysis. The model included direct genetic and residual effects as random effects, the fixed effects of contemporary group, and the linear and quadratic effects of animal age at recording (except for AFC, GBW, and GWY) and age of cow at calving as covariates (except for MW). The numbers of days from birth to weaning and from weaning to yearling were included as covariates for GBW and GWY, respectively. Estimated direct heritabilities were 0.43 ± 0.02 (MW), 0.33 ± 0.01 (WW), 0.36 ± 0.01 (YW), 0.28 ± 0.02 (GBW), 0.31 ± 0.01 (GWY), 0.44 ± 0.02 (WHH), 0.48 ± 0.02 (YHH), 0.44 ± 0.01 (SC), and 0.16 ± 0.03 (AFC). Genetic correlations between MW and productive traits were positive and of medium to high magnitude (ranging from 0.47 ± 0.03 to 0.71 ± 0.01). A positive and low genetic correlation was observed between MW and SC (0.24 ± 0.04). A negative genetic correlation (-0.19 ± 0.03) was estimated between MW and AFC. Selection to increase weight or weight gains at any age, as well as hip height, will change MW in the same direction. Selection for higher SC may lead to a long-term increase in MW. The AFC can be included in selection indices to improve the reproductive performance of beef cattle without significant changes in MW.

Genetic associations of visual scores with subsequent rebreeding and days to first calving in Nellore cattle.

Records of Nellore animals born from 1990 to 2006 were used to estimate genetic correlations of visual scores at yearling (conformation, C; finishing precocity, P; and muscling, M) with primiparous subsequent rebreeding (SR) and days to first calving (DC), because the magnitude of these associations is still unknown. Genetic parameters were estimated by multiple-traits Bayesian analysis, using a nonlinear (threshold) animal models for visual scores and SR and a linear animal models for weaning weight (WW) and DC. WW was included in the analysis to account for the effects of sequential selection. The posterior means of heritabilities estimated for C, P, M, SR and DC were 0.24 ± 0.01, 0.31 ± 0.01, 0.30 ± 0.01, 0.18 ± 0.02 and 0.06 ± 0.02, respectively. The posterior means of genetic correlations estimated between SR and visual scores were low and positive, with values of 0.09 ± 0.02 (C), 0.19 ± 0.03 (P) and 0.18 ± 0.05 (M). On the other hand, negative genetic correlations were found between DC and C (-0.11 ± 0.09), P (-0.19 ± 0.09) and M (-0.16 ± 0.09). The primiparous rebreeding trait has genetic variability in Nellore cattle. The genetic correlations between visual scores, and SR and DC were low and favourable. The genetic changes in C, P and M were 0.02, 0.03 and 0.03/year, respectively. For SR and DC, genetic trends were 0.01/year and -0.01 days/year, respectively, indicating that the increase in genetic merit for reproductive traits was small over time. Direct selection for visual scores together with female reproductive traits is recommended to increase the fertility of beef cows.

Protective effects of Syzygium cumini seed extract against methylmercury-induced sistemic toxicity in neonatal rats.

Syzygium cumini (L.) Skeels (Sc) belongs to the medicinal plants with an important source of phenolic compounds. Sc has been shown to possess antioxidant and anti-inflammatory properties. Methylmercury (MeHg), a highly toxic environmental pollutant, induces oxidative stress and dysfunction in many cell types. This study was aimed to evaluate the effect of aqueous seed extract of Sc (ASc) on MeHg-induced toxicity in rats. Two-day-old rats (P2) received a single dose of MeHg (10 mg/kg) and two doses of ASc (0.9 mg/kg) per os. After two days, the effects of the treatment were investigated in the cerebral cortex, hippocampus, kidney, liver and urine samples. Our results demonstrated that N-acetyl-ß-D: -glucosaminidase (NAG) activity in the kidney and urine, the lipid peroxidation levels in the liver and kidney samples, as well as the adenosine deaminase (ADA) activity in the hippocampus, kidney and liver were higher in MeHg-group when compared to the control group. The administration of ASc reverted the toxic effects of MeHg. It is noteworthy to observe that the main compounds present in the ASc, as gallic acid (the major component), chlorogenic acid and rutin, might be the responsible for such benefit, since they were found to display antioxidant properties.

Breeding value accuracy estimates for growth traits using random regression and multi-trait models in Nelore cattle.

We quantified the potential increase in accuracy of expected breeding value for weights of Nelore cattle, from birth to mature age, using multi-trait and random regression models on Legendre polynomials and B-spline functions. A total of 87,712 weight records from 8144 females were used, recorded every three months from birth to mature age from the Nelore Brazil Program. For random regression analyses, all female weight records from birth to eight years of age (data set I) were considered. From this general data set, a subset was created (data set II), which included only nine weight records: at birth, weaning, 365 and 550 days of age, and 2, 3, 4, 5, and 6 years of age. Data set II was analyzed using random regression and multi-trait models. The model of analysis included the contemporary group as fixed effects and age of dam as a linear and quadratic covariable. In the random regression analyses, average growth trends were modeled using a cubic regression on orthogonal polynomials of age. Residual variances were modeled by a step function with five classes. Legendre polynomials of fourth and sixth order were utilized to model the direct genetic and animal permanent environmental effects, respectively, while third-order Legendre polynomials were considered for maternal genetic and maternal permanent environmental effects. Quadratic polynomials were applied to model all random effects in random regression models on B-spline functions. Direct genetic and animal permanent environmental effects were modeled using three segments or five coefficients, and genetic maternal and maternal permanent environmental effects were modeled with one segment or three coefficients in the random regression models on B-spline functions. For both data sets (I and II), animals ranked differently according to expected breeding value obtained by random regression or multi-trait models. With random regression models, the highest gains in accuracy were obtained at ages with a low number of weight records. The results indicate that random regression models provide more accurate expected breeding values than the traditionally finite multi-trait models. Thus, higher genetic responses are expected for beef cattle growth traits by replacing a multi-trait model with random regression models for genetic evaluation. B-spline functions could be applied as an alternative to Legendre polynomials to model covariance functions for weights from birth to mature age.

Metabolic depletion of synaptosomal enzymes linked with neurotoxicity and ovarian dysfunction by phenolic antioxidants of Croton zambsicus leaves in rats exposed to chronic mixture of anthropogenic toxicant.

A complex mixture of organic contaminants and metals is associated with neuron-fertility disorders and studies have demonstrated that phenolic antioxidants from herbal origin, possesses a strong protective potential. This study aimed to investigate the protection of phenolic croton zambesicus (C-ZAMB) leaves against neuro-ovarian damage in rats exposed to chronic mixture of anthropogenic toxicants (EOMABRSL). The animals were divided into five groups (n = 10): Group I was given 0.5 ml of distilled water only; Group II received 0.5 ml of EOMABRSL for 98 days; Group III received 0.5 ml of EOMABRSL for 70 days and withdrew for 28 days; Group IV received 0.5 ml of EOMABRSL for 70 days +400 mg/kg phenolic C-ZAMB for 28 days; Group V received 400 mg/kg C-ZAMB only for 28 days via oral route. Both non-withdrawal and withdrawal EOMABRSL-exposed animals exhibited neuro-ovarian impairment by up-regulating neuronal 51 eco-nucleotidase (51ENT), acetylcholinesterase (AChE), butrylcholinesterase (BuChE), synaptosomal monoamine oxidase-A (MAO-A) with altered cerebral antioxidants. Similarly, exposure to EOMABRSL for 98 and 70 days caused ovarian injury by amplifying the activity of 51ENT with corresponding decline of fertility index, lactate dehydrogenase (LDH) and Δ5 17ß-hydroxyl steroid dehydrogenase (Δ517ß-HSD). EOMABRSL intoxication also increased the neuro-ovarian MDA content with reduced numbers of neonates. Phenolic antioxidants from C-ZAMB leaves identified by High Pressure Liquid Chromatography (HPLC) ameliorated the chronic EOMABRSL intoxication. The treatment also prevented ovarian lesions by depleting MDA content and improved antioxidant status. Thus, confirming its neuro-ovarian protection.

Genetic analysis of female reproductive efficiency, scrotal circumference and growth traits in Nelore cattle.

This study estimated the genetic variability and correlations between growth and reproductive traits in Nelore cattle. Annual genetic changes in female reproductive traits were also evaluated using repeated measures. Direct heritability was moderate for the growth traits and scrotal circumference (0.235 ±â€¯0.015 to 0.443 ±â€¯0.006), indicating genetic variability in these traits in the population studied. Maternal heritability was low for weaning height (0.042 ±â€¯0.012) and weaning weight (0.112 ±â€¯0.013). Regarding female reproductive traits, gestation length (GL) exhibited a slightly higher heritability (0.179 ±â€¯0.006) than days to calving (DC) and calving interval (CI) (0.123 ±â€¯0.006 and 0.105 ±â€¯0.008, respectively). Repeatability was lower for GL (0.222 ±â€¯0.006) compared to DC (0.318 ±â€¯0.004) and CI (0.406 ±â€¯0.006). Moderate and positive genetic correlations were obtained between the growth traits and scrotal circumference, ranging from 0.193 ±â€¯0.019 to 0.519 ±â€¯0.007. Weaning height showed low and positive genetic associations with GL (0.138 ±â€¯0.007) and CI (0.189 ±â€¯0.016), but was not correlated with DC (-0.016 ±â€¯0.011). Similarly, weaning weight, yearling height or yearling weight was not associated with any of the female reproductive traits. The genetic correlations between scrotal circumference and female reproductive traits were negative and favorable, but low: -0.116 ±â€¯0.020 (GL), -0.084 ±â€¯0.028 (DC), and -0.054 ±â€¯0.038 (CI). Favorable genetic associations were estimated between all female reproductive traits, ranging from 0.170 ±â€¯0.040 to 0.442 ±â€¯0.050. Genetic changes were favorable for GL and CI (-0.02 days/year and -0.11 days/year, respectively) and unfavorable for DC (0.16 days/year). In conclusion, selection for higher growth using the estimated breeding values for height and weight will not affect the reproductive performance of Nelore females. Nonetheless, simultaneous selection for growth and reproductive traits is possible.

Genetic analysis of age at first calving, accumulated productivity, stayability and mature weight of Nellore females.

The female reproductive performance, productivity and size are strongly associated with production efficiency of herds raised in a tropical environment. The age at first calving (AFC), accumulated productivity (AP), stayability (STAY) and mature weight (MW) could be used as indicators of these traits. In this study, the genetic parameters and correlations between AFC, AP, STAY and MW measured in Nellore females were estimated, in order to provide support for the beef cattle evaluation programs. In addition, the genetic changes for these traits were obtained. The (co)variance components were estimated by Gibbs sampling by four-trait multivariate analysis, using a threshold animal model for STAY and linear animal model for the other traits (AFC, AP and MW). Heritability of AFC, AP and STAY showed low values, with posterior means of 0.13 ± 0.02, 0.14 ± 0.01 and 0.19 ± 0.03, respectively. On the other hand, for MW were estimated mean heritability of 0.44 ± 0.03 and repeatability of 0.77 ± 0.03, demonstrating the importance of genetic and permanent environmental effects for the expression of beef cows' size. The AFC showed null genetic correlation with AP (-0.06 ± 0.12) and MW (0.01 ± 0.09) and low and negative with STAY (-0.15 ± 0.11). The AP showed high genetic correlation with STAY (0.86 ± 0.03) and weak with MW (0.23 ± 0.09). Positive and moderate genetic association was estimated between STAY and MW (0.66 ± 0.05). Annual direct genetic trends of 0.19 kg, 0.30 units and 0.10 kg were estimated for AP, STAY and MW, respectively, and were significant (P < 0.05) for STAY and MW. For AFC, negative and favorable annual genetic change was estimated (-0.08 months, P < 0.05). In this population, the selection of heifers for an early reproductive age should have little influence, however favorable, in the time that the cows remain in the herd. The use of AP as a selection criterion should result in smaller changes in the females' mature weight when compared to selection based on STAY.

Effect of mature size and body condition of Nelore females on the reproductive performance.

The size and body condition of cows can affect their reproductive efficiency. However, few studies reported genetic correlations between these traits in beef cattle. Thus, we estimated the genetic parameters and correlations between weight (MW), height (MH) and body condition score (BCS) of cows and reproductive traits (SC: scrotal circumference, AFC: age at first calving, GL: gestation length, DC: days to calving, and CI: calving interval) in Nelore animals. In addition, it has also obtained direct and correlated responses aiming at determining whether changes in cow size and body condition may affect the herd reproductive performance. A series of two-trait Bayesian analyzes were performed including MW, MH or BCS with each of the reproductive traits. The heritability estimated for MW, MH and BCS were 0.46 ±â€¯0.02, 0.35 ±â€¯0.01 and 0.17 ±â€¯0.02, indicating an involvement of additive gene action mainly in cows' size determination. For the reproductive traits of females, heritability ranged from 0.05 ±â€¯0.00 for CI to 0.18 ±â€¯0.01 for GL, and was 0.37 ±â€¯0.01 for SC. Low repeatability were estimates for GL (0.19 ±â€¯0.00), DC (0.19 ±â€¯0.00) and CI (0.05 ±â€¯0.00). The MW was positive correlated with AFC (0.23 ±â€¯0.08), CI (0.25 ±â€¯0.15) and, with lower magnitude, of GL (0.14 ±â€¯0.03). Null genetic correlations were obtained between MW with SC (0.03 ±â€¯0.03) and DC (-0.01 ±â€¯0.04). The MH showed positive and low genetic association with all female reproductive traits, but negative with SC (-0.08 ±â€¯0.03). Negative and favorable genetic correlations were estimated between BCS and females reproductive traits, but unfavorable with SC (-0.13 ±â€¯0.06). In summary, the negative impact of increase the size of Nelore females on their reproductive performance is expected to be small in tropical regions. The use of sires with high genetic breeding values for SC should result in slight reduction of BCS of cows, but no effective genetic response in female size is expected. Selection based on BCS should promote little improvement in reproductive efficiency of cows.