Inbreeding depression on production and reproduction traits of buffaloes from Brazil

The objective of this study was to evaluate the influence of inbreeding depression on traits of buffaloes from Brazil. Specifically, the traits studied were body weight at 205 and 365 days of age, average daily gain from birth to 205 days (ADG_205), average daily gain between 205 and 365 days (ADG205_365) in Mediterranean buffaloes, and milk yield, lactation length, age of first calving and calving intervals in Murrah buffaloes. Inbreeding effects on the traits were determined by fitting four regression models (linear, quadratic, exponential and Michaelis-Menten) about the errors generated by the animal model. The linear model was only significant (P<0.05) for growth traits (exception of ADG205_365). The exponential and Michaelis-Menten models were significant (P<0.01) for all the studied traits while the quadratic model was not significant (P>0.05) for any of the traits. Weight at 205 and 365 days of age decreased 0.25kg and 0.39kg per 1% of increase in inbreeding, respectively. The inbred animals (F=0.25) produced less milk than non-inbred individuals: 50.4kg of milk. Moreover, calving interval increased 0.164 days per 1% of increase in inbreeding. Interestingly, inbreeding had a positive effect on age at first calving and lactation length, decreasing age of first calving and increasing lactation length. © 2012 Japanese Society of Animal Science.

Long-term effects of perinatal androgenization on reproductive parameters of male rat offspring androgenization and male rat reproduction

It is known that during sex differentiation, fetal androgens are critical determinants of the male phenotype. Although testosterone is necessary for normal development of male sexual behavior, perinatal androgen treatment can result in disruption of normal male sexual reproduction. Pregnant Wistar rats were administered either corn oil (vehicle) or testosterone propionate at 0.2 mg/kg from gestational day 12 until the end of lactation and the reproductive function of male offspring was evaluated at 90 (adulthood) and 270 (middle age) days of age. Perinatal androgenization in the rat provoked a reduction in sperm production and reserves in adulthood that did not affect fertility and did not persist at more advanced ages, as shown by the results at post-natal day 270. If perinatal androgenization promotes similar effects in humans of reproductive age, the results of the present work can impact male reproduction health, given the less efficient spermatogenesis and lower sperm reserves in the human epididymis, compared to rodents. © Georg Thieme Verlag KG Stuttgart. New York.

Desmame precoce: Falta de conhecimento ou de acompanhamento?

Objective: To assess the knowledge of women and the instructions received on breastfeeding during pregnancy and after childbirth, and their influence on breastfeeding practice. Method: This study was a longitudinal investigation following 84 pairs of mothers and babies from pregnancy through the sixth month of baby's life. In the first phase of the research, interviews were made with the pregnant women at home and at Basic Health Units to collect information about their intentions and knowledge of breastfeeding. In the second phase of the research, mothers and babies were followed up from the first to sixth month of baby's life to record the difficulties of breastfeeding and reasons for weaning. Results: In the first month, 94.3% (82) of the babies were breastfed, but only 49.4% (43) were breastfed exclusively. At the end of the sixth month of life, 43.7% (38) of the babies had already been weaned. No mother breastfed exclusively her baby within the sixth month. During pregnancy, 60.7% (51) of the mothers had no instructions about breastfeeding and 83.4% (70) of the mothers received instructions on breastfeeding after childbirth. Most mothers (76.2%) knew about the ideal breastfeeding period. Seventy-three (86.9%) mothers believed that breastfeeding was beneficial for the baby, but only 41 (48.8%) of them really breastfed. Only 11 (13.1%) mothers were followed up by the public health system team during lactation. Conclusion: Although most women had been instructed during pregnancy or after childbirth and had knowledge of breastfeeding, early weaning occurred. Advising is important, but the support and follow up of the mothers are of utmost importance for a successful breastfeeding practice.

Genetic evaluation using multi-trait and random regression models in Simmental beef cattle

The Brazilian Association of Simmental and Simbrasil Cattle Farmers provided 29,510 records from 10,659 Simmental beef cattle; these were used to estimate (co)variance components and genetic parameters for weights in the growth trajectory, based on multi-trait (MTM) and random regression models (RRM). The (co)variance components and genetic parameters were estimated by restricted maximum likelihood. In the MTM analysis, the likelihood ratio test was used to determine the significance of random effects included in the model and to define the most appropriate model. All random effects were significant and included in the final model. In the RRM analysis, different adjustments of polynomial orders were compared for 5 different criteria to choose the best fit model. An RRM of third order for the direct additive genetic, direct permanent environmental, maternal additive genetic, and maternal permanent environment effects was sufficient to model variance structures in the growth trajectory of the animals. The (co)variance components were generally similar in MTM and RRM. Direct heritabilities of MTM were slightly lower than RRM and varied from 0.04 to 0.42 and 0.16 to 0.45, respectively. Additive direct correlations were mostly positive and of high magnitude, being highest at closest ages. Considering the results and that pre-adjustment of the weights to standard ages is not required, RRM is recommended for genetic evaluation of Simmental beef cattle in Brazil. ©FUNPEC-RP.

Effects of a single nucleotide polymorphism in the leptin gene on the productive traits of dairy buffaloes (Bubalus bubalis)

The gene responsible for coding the leptin hormone has been associated with productive and reproductive traits in cattle. In dairy cattle, different polymorphisms found in the leptin gene have been associated with several traits of economic interest, such as energy balance, milk yield and composition, live weight, fertility and dry matter consumption. The aim of this study was to detect genetic variability in the leptin gene of buffaloes and to test possible associations with milk yield, fat and protein percentages, age at first calving and first calving interval. Three genotypes (AA, AG and GG) were identified by polymerase chain reaction-restriction fragment length polymorphism, which presented genotypic frequencies of 0.30, 0.54 and 0.16, respectively. The allele frequencies were 0.57 for the A allele and 0.43 for the G allele. No significant effects were found in the present study, but there is an indicative that leptin gene affects lipid metabolism. © 2013 Springer Science+Business Media Dordrecht.

Proteinograma do soro lácteo de ovelhas da raça santa inês em diferentes fases de lactação

This study aimed to evaluate the influence of lactation phases on the proteinogram of whey protein in Santa Inês ewes. Ewes were accompanied in a semi-intensive system using the same sanitary and nutritional management evaluated at 15, 30, 60 and 90 days postpartum (end of weaning and lactation). Clinical examination of the mammary gland was carried out through and bacteriological culture. The screening of the material resulted in 44 milk samples of healthy glands concurrent negative by CMT and bacteriological culture exam. For obtaining the whey protein renin solution was used. The whey was fractionated into aliquots and kept in the -80C freezer to later separation of protein fractions. For determination of total protein of whey protein was employed the biuret, observing the linearity of the test. Separation of protein fractions was performed, using polyacrylamide gel containing sodium dodecyl sulfate (SDS-PAGE). Eigth protein were observed including lactoferrin, serum albumin, IgA, IgG (heavy chain IgG (IgG CP), light chain IgG (IgG CL), ß-lactoglobulin, a-lactalbumin and proteins identified as PM 15000 and PM 29000. No significant difference was observed at different stages of lactation in the following protein: IgA (P>0.3895), lactoferrin (P>0.1611), PM 29000 (P>0.4879), α-lactalbumin (P>0.0799) and PM15000 (P>0.4494). In total protein (P<0.0022), albumin protein (P<0.0377) and IgG (P<0.0354) it was observed a significant variation in the first moments of observations, in the ß-lactoglobulin protein (P<0.0005) there was significant variation with reduction of 15 to 30 days postpartum with progressive elevation until the last stage of lactation (90 days postpartum). The SDS-PAGE technique allowed the quantification of eigth whey proteins in health ewes. The protein fractions identified reflect the profile of whey to ovine species, with influence of stages of lactation in albumin, IgG and ß-lactoglobulin.

Excess androgen during perinatal life alters steroid receptor expression, apoptosis, and cell proliferation in the uteri of the offspring

Exposure to environmental chemicals may contribute to reproductive disorders, especially when it occurs in critical periods of development. The female reproductive system can be a target for androgens derived from environmental contaminants or pathological conditions. The purpose of this study was to assess the long-term effects of androgens on uterine tissue after maternal exposure limited to the time of gestation and lactation. Pregnant Wistar rats were treated with testosterone propionate (TP) at 0.05. mg/kg, 0.1. mg/kg, 0.2. mg/kg or corn oil (vehicle), s.c., from gestational day 12 until the end of lactation. The results show changes in the pattern of expression of receptors for estrogen, progesterone, and androgen at all doses tested, and decreases in both apoptosis and cell proliferation indices at 0.1 and 0.2. mg/kg. We conclude that early TP exposure, under these experimental conditions, causes changes in cellular and molecular parameters that are essential for normal uterine function in the adult. © 2013 Elsevier Inc.

Multiple-trait random regression models for the estimation of genetic parameters for milk, fat, and protein yield in buffaloes

In this study, genetic parameters for test-day milk, fat, and protein yield were estimated for the first lactation. The data analyzed consisted of 1,433 first lactations of Murrah buffaloes, daughters of 113 sires from 12 herds in the state of São Paulo, Brazil, with calvings from 1985 to 2007. Ten-month classes of lactation days were considered for the test-day yields. The (co)variance components for the 3 traits were estimated using the regression analyses by Bayesian inference applying an animal model by Gibbs sampling. The contemporary groups were defined as herd-year-month of the test day. In the model, the random effects were additive genetic, permanent environment, and residual. The fixed effects were contemporary group and number of milkings (1 or 2), the linear and quadratic effects of the covariable age of the buffalo at calving, as well as the mean lactation curve of the population, which was modeled by orthogonal Legendre polynomials of fourth order. The random effects for the traits studied were modeled by Legendre polynomials of third and fourth order for additive genetic and permanent environment, respectively, the residual variances were modeled considering 4 residual classes. The heritability estimates for the traits were moderate (from 0.21-0.38), with higher estimates in the intermediate lactation phase. The genetic correlation estimates within and among the traits varied from 0.05 to 0.99. The results indicate that the selection for any trait test day will result in an indirect genetic gain for milk, fat, and protein yield in all periods of the lactation curve. The accuracy associated with estimated breeding values obtained using multi-trait random regression was slightly higher (around 8%) compared with single-trait random regression. This difference may be because to the greater amount of information available per animal. © 2013 American Dairy Science Association.

Estimates of genetic parameters and eigenvector indices for milk production of Holstein cows

The objectives of the present study were to estimate genetic parameters of monthly test-day milk yield (TDMY) of the first lactation of Brazilian Holstein cows using random regression (RR), and to compare the genetic gains for milk production and persistency, derived from RR models, using eigenvector indices and selection indices that did not consider eigenvectors. The data set contained monthly TDMY of 3,543 first lactations of Brazilian Holstein cows calving between 1994 and 2011. The RR model included the fixed effect of the contemporary group (herd-month-year of test days), the covariate calving age (linear and quadratic effects), and a fourth-order regression on Legendre orthogonal polynomials of days in milk (DIM) to model the population-based mean curve. Additive genetic and nongenetic animal effects were fit as RR with 4 classes of residual variance random effect. Eigenvector indices based on the additive genetic RR covariance matrix were used to evaluate the genetic gains of milk yield and persistency compared with the traditional selection index (selection index based on breeding values of milk yield until 305 DIM). The heritability estimates for monthly TDMY ranged from 0.12 ± 0.04 to 0.31 ± 0.04. The estimates of additive genetic and nongenetic animal effects correlation were close to 1 at adjacent monthly TDMY, with a tendency to diminish as the time between DIM classes increased. The first eigenvector was related to the increase of the genetic response of the milk yield and the second eigenvector was related to the increase of the genetic gains of the persistency but it contributed to decrease the genetic gains for total milk yield. Therefore, using this eigenvector to improve persistency will not contribute to change the shape of genetic curve pattern. If the breeding goal is to improve milk production and persistency, complete sequential eigenvector indices (selection indices composite with all eigenvectors) could be used with higher economic values for persistency. However, if the breeding goal is to improve only milk yield, the traditional selection index is indicated. © 2013 American Dairy Science Association.

Estimación de parámetros genéticos para producción de leche en el día de control en búfalas de primer parto

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeitos do tabagismo passivo associado ao exercício físico durante prenhez e lactação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da exposição à fumaça de cigarro sobre a expressão de GLUT4 em ratas prenhes e lactantes e sua prole

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Impacto da desnutrição fetal/neonatal e do exercício durante a recuperação nutricional sobre lipídios teciduais e homeostase glicêmica de ratos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Desenvolvimento sexual da prole de ratas submetidas à restrição proteica em diferentes períodos da prenhez e lactação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Perfil bioquímico, condição microbiológica e celuridade do leite de búfalas

Pós-graduação em Medicina Veterinária - FCAV