J.D. Guimarães

Heritability Estimate and Genetic Correlations of Reproductive Features in Nellore Bulls, Offspring of Super Precocious, Precocious and Normal Cows Under Extensive Farming Conditions

The present work aimed to estimate heritability and genetic correlations of reproductive features of Nellore bulls, offspring of mothers classified as superprecocious (M1), precocious (M2) and normal (M3). Twenty one thousand hundred and eighty-six animals with average age of 21.29 months were used, evaluated through the breeding soundness evaluation from 1999 to 2008. The breeding soundness features included physical semen evaluation (progressive sperm motility and sperm vigour), semen morphology (major, minor and total sperm defects), scrotal circumference (SC), testicular volume (TV) and SC at 18 months of age (SC18). The components of variance, heritability and genetic correlations for and between the features were estimated simultaneously by restricted maximum likelihood, with the use of the vce software system vs 6. The heritability estimates were high for SC18, SC and TV (0.43, 0.63 and 0.54; 0.45, 0.45 and 0.44; 0.42, 0.45 and 0.41, respectively for the categories of mothers M1, M2 and M3) and low for physical and morphological semen aspects. The genetic correlations between SC18 and SC were high, as well as between these variables with TV. High and positive genetic correlations were recorded among SC18, SC and TV with the physical aspects of the semen, although no favourable association was verified with the morphological aspects, for the three categories of mothers. It can be concluded that the mothers sexual precocity did not affect the heritability of their offspring reproduction features.

Reproductive Parameters of Mangalarga Marchador Mares in a Commercial Embryo Transfer Programme

The objective of this study is to evaluate the reproductive efficiency in donors and recipient Mangalarga Marchador mares in commercial programmes of embryo transfer (ET) and the effects of some reproductive characteristics and ET methodology on conception rates in the recipient mares. A total of 1140 flushing procedures were performed and 830 embryos (72.8%) were recovered. There were no differences between the rates of embryonic recovery in the different breeding seasons (p > 0.05) and 92.8% of the recovered embryos were 8-9 days old. There was no difference in the embryonic recovery regarding the collection order from the first to the ninth embryo collection along the breeding season, as well as among mares inseminated during the foal heat or subsequent cycles (p > 0.05). Pregnancy rates observed in the total period of all reproductive seasons at 15, 30, 45 and 60 days of pregnancy were 73.4, 69.9, 66.7 and 64.5%, respectively. Differences in pregnancy rate and early embryonic loss rates were not observed between embryos transferred immediately after collection (66.8% and 13.5%) and embryos transported at room temperature for periods of < 1 h (62.9% and 14.4%; p > 0.05). Pregnancy rates were higher when the interval between ovulations of donor and recipient mares remained between -3 and -2 days (p < 0.05), and the lowest rates were observed for intervals of -6 days (p < 0.05) with intermediary values for intervals of -1, 0 and +1 (p > 0.05). Embryonic loss rates, however, did not differ between intervals of ovulations synchronism between donor and recipient mares (p > 0.05). This flexibilization in the ovulatory synchronism between donor and recipient mares optimizes the use of recipient mares, thus reducing costs and facilitating management of horse breeding farms.

Ultrassonografia testicular em caprinos jovens da raça Alpina

The purpose of this study was to observe changes in the testicular parenchyma of male goats. Changes were observed in terms of goat age, evaluating the echotexture and ultrasound viability in the testicles. Four animals were used, ranging from six to 13 months of age. The echographic examinations were performed every 15 days to assess echotexture of the testicle. The testicular parenchyma appeared moderately echogenic and homogeneous. Similar results were observed in testicular echotexture during the evaluation period. The highest results appearing during the eighth month of age, when the testicular volume was also highest; such changes were related to the regional photoperiod. The ultrasound evaluation of the testicles was shown to be an effective method, ultimately capable of detecting changes in testicular parenchyma over time, being an alternative to differentiation normal and pathological conditions in goats.

Estimativas de herdabilidades e correlações genéticas entre características reprodutivas em touros da raça Nelore

Estimates of phenotypic, genetics and residual variances for reproductive traits in 5903 Nellore bulls were obtained. The experimental model used was multiple trait derivative-free restricted maximum likelihood. The values obtained for heritability were 0.24±0.05 for scrotal circumference at 450 days of age and 0.37±0.05 at 21 months for age at the time of the breeding soundness evaluation; 0.24±0.05 and 0.26±0.05 for left and right testicle length; 0.29±0.05 and 0.31±0.05 for left and right testicle width; 0.12±0.04 for testicle format; 0.33±0.06 for testicle volume; 0.11±0.03 for gross motility; 0.08±0.03 for individual motility and 0.05±0.02 for spermatic vigor; 0.20±0.04, 0.03±0.02 and 0.19±0.04 for larger defects, smaller defects and total defects, respectively. The values for heritability for testicular biometric characteristics were moderate to high while the seminal characteristics, presented low values. Genetic correlations between scrotal circumference with all the reproductive traits were favorable, suggesting the scrotal circumference as a feature of choice in the selection of bulls.

Immotile short-tail sperm defect in Nelore (Bos taurus indicus) breed bulls.

This case study reported the presence of short tail sperm defect in the semen of three Nelore breed bulls. The sperm presented 0% of motility in the three animals evaluated and a total of 70%, 61% and 34% of pathologies of the intermediate piece of the tail respectively for animals 1, 2 and 3. It was identified that animals 2 and 3 had high degree of inbreeding, although no relationship was found with animal 1. Animal 2 was the only one that presented inbreeding coefficient (6.25%). His half-sib (animal 3) and animal 1, from the same herd, had shown no inbreeding, showing that inheritance is not the only determinant factor for its incidence on Nelore males.

Efeito de fontes de óleo e níveis de suplementação de vitamina E na ração sobre as características físicas e morfológicas do sêmen in natura de suínos

The addition of oil sources and dietary vitamin E supplementation was evaluated on the characteristics of fresh boar sperm. Twenty-four mature Dalboar 85 boars of proven fertility and in routine semen production for artificial insemination were randomly distributed in a factorial arrangement 2 X 3, with two oil sources, soy and salmon, and three antioxidant levels: 150, 300, and 450mg/kg of vitamin E. Volume, total motile sperm, hyposmotic swelling test, percentage of live cell, and morphology did not differ (P 0.05). Salmon oil treatment showed the lowest (P<0.05) concentration of total antioxidants in the semen. Vitamin E and concentration of total antioxidant showed a linear effect (P<0.05). The semen vigor and the concentration of total antioxidants were improved by oil sources, but the sperm concentration was dependent on the levels of vitamin E. Therefore, salmon oil can be used in the diet of male pigs.

Perfil metabólico de touros da raça Nelore (Bos taurus indicus) confinados e tratados com somatotrofina bovina recombinante (r-bST)

This study was carried out to evaluate the effect of recombinant bovine somatotropin (r-bST) administration on profiles of blood metabolites of two different ages Nellore bulls. Sixteen bulls were randomly allotted in a factorial arrangement 2 x 2 (ages: youngs and adults; and r-bST dose: 0 and 500 mg) with four animals per treatment. The mean ages of the young and adult animals were 13.37 and 20.62 months, respectively. Four animals per treatment received saline solution or r-bST 500mg, every 14 days, totaling nine applications per animal during 120 days. The Bulls were fed corn silage and concentrated diet based on corn crumb and soybean meal, twice a day, in individual stalls. Blood was collected every three days for metabolic evaluation. The statistical analyses of the data were performed in three applications, considering three periods (1, 2 and 3). Non-esterified fatty acid (NEFA) concentrations were weekly analyzed. Serum cholesterol, total protein and glucose levels were affected either by period or the treatment (P 0.05).

The use of ultrasonography in the reproductive evaluation of boars

The objective was to study the use of ultrasound as a complementary test in the breeding soundness evaluation in male pigs and study the pattern of echogenicity of the testicular parenchyma in boars of different racial groups. Twenty-six adult boars from four different racial groups were used, 10 from the Piau breed (group 1), four from the commercial and finishing group (group 2), six Pietrain breed (group 3) and six from the Duroc breed (group 4). All animals were evaluated for breeding soundness evaluation and the ultrasound examination of the testicles. The groups of animals that were evaluated showed no difference in the main semen parameters that were evaluated, except for the sperm volume, concentration of the ejaculated sperm and the supravital staining; the lowest figures were for the animals from the Piau breed (group 1). In relation to the testicular biometrics, Duroc animals (group 4) had a greater scrotal width compared to the other groups. But when we assessed the intensity of pixels of the testicles, there was a difference between groups. The groups 2 (finishing animals), 3 (Pietrain) and 4 had no difference between themselves. Group 3 had greater pixel intensity in relation to group 1. Of the 26 animals studied, five showed an abnormality during ultrasound evaluation, like hydrocele, hyperechoic mass in the testicular parenchyma, cyst in the head of the epididymis and the presence of fluid in the head and tail of the epididymis. The various animal groups studied did not differ in the principal reproductive parameters evaluated, showing that despite the great variability of reproductive traits between breeds and within the same breed, the breeding soundness evaluation, the more complete it is, is essential for the selection of breeders and the ultrasonography of the reproductive system becomes an important addition in this examination.

Influência da condição corporal ao parto no balanço energético e desempenho reprodutivo de cabras leiteiras no pós-parto

O estudo teve como objetivo avaliar a influencia da condicao corporal (CC) ao parto no balanco energetico (BE) e o desempenho reprodutivo de cabras Alpinas no pos-parto. Foram utilizadas 68 cabras distribuidas em tres grupos (G), sendo: G1- cabras com baixa CC (CC entre 1,5 e 2,5); G2: cabras com moderada CC (entre 2,75 e 3,5) e G3: cabras com alta CC (entre 3,75 e 5,0). Os animais receberam dieta (silagem de milho e concentrado, com 18% de proteina bruta e 1,7Mcal/kg de materia seca de energia liquida) ad libitum. As avaliacoes foram feitas nas oito primeiras semanas de lactacao, para determinacao do BE, do intervalo do parto a primeira ovulacao e ao primeiro estro e da concentracao plasmatica de progesterona. Os dados foram analisados por analise de variância a 5% de probabilidade. Nao houve efeito da CC ao parto sobre o BE dos animais. Todas as cabras apresentaram BE negativo ao parto, com mudanca para BE positivo aos 51, 58 e 64 dias pos-parto, respectivamente. Nao houve diferenca na concentracao plasmatica de progesterona nos tres grupos, sendo caracterizada funcao luteal (concentracao ≥1ng/dL) em apenas 5,9% dos animais avaliados. O intervalo do parto a primeira ovulacao foi de 46 dias. Apenas 4,4% das cabras exibiram estro. Cabras leiteiras de media producao, entre 2,5 e 3,0kg de leite/dia, entram em BE negativo ao parto, independentemente da CC apresentada, influenciando negativamente o reinicio da atividade ovariana no pos-parto.

Influência do Hormônio do Crescimento na concentração de testosterona plasmática e nas características seminais de touros jovens e adultos da raça Nelore

The aim of this trial was to study the effect of Growth Hormone (GH) on the seminal parameters and testosterone profile from Nellore bulls. Sixteen bulls were allocated in a 2 x 2 factorial arrangement (two ages and two r-bST levels), with four animals per treatment. The r-bST was injected every 14 days, with a total of nine injections per animal, during the 120 days of the experimental period. The semen collections were done every 15 days and blood samples were collected in four hour intervals for 24 hours, and in 30 day intervals from the first r-bST injection for testosterone profile. The semen of adult bulls treated with r-bST showed greater MOT and VIG (P 0.05) by the r-bST treatment. The physical measurements of the semen of young animals was also unaffected (P>0.05) by r-bST injection. However, the treatment with r-bST decreased the number of minor morphologic defects (narrow head, giant head, small normal head, round head, free normal head, abaxial implantation, simple bent tail and distal droplet) compared to untreated young bulls (P<0.05). The serum testosterone concentration was influenced (P<0.05) by treatment, at 120 days after the first injection of r-bST and they showed a tendency of three picks in a 24 hour period of sampling