Rogério Oliveira Pinho

Uso de própolis e ácido ascórbico na criopreservação do sêmen caprino

The objectives of this study were to verify whether propolis and ascorbic acid have an effect on plasmatic membrane integrity of goat spermatozoa and investigate the potential of these antioxidants in the use of goats spermatozoa cryopreservation extenders. Five adult boars were used of the Alpine (n = 2) and Saanen (n = 3) breeds. After semen collection, the evaluation consisted of the physical and morphological exam, live and dead cells (supravital test) and hyposmotic swelling test. Afterwards, the fresh semen was diluted with the Bioxcell® extender (control); Bioxcell® + 0.25% freeze dried propolis extract); Bioxcell® + 0.5% freeze dried propolis extract); Bioxcell® + 0.05% ascorbic acid) or Bioxcell® + 0.25% ascorbic acid). After final dilutions, the sperm motility and vigor were assessed obtained in each extender, and then the semen was sealed, cooled and frozen. In fresh semen, the physical and morphological aspects and the results of the supravital test and hyposmotic swelling test did not differ between animals or breeds. The general means of the sperm motility and vigor, supravital test and hyposmotic swelling test obtained immediately after thawing and after three hours of heat resistence test were different, so that the extender with ascorbic acid and the control were similar and higher than the extenders containing propolis. The ascorbic acid maintained the structural integrity of the spermatozoa membrane during the cryopreservation process and its viability after the heat resistance test, and may be an alternative in extender composition for cryopreservation of goat semen; the propolis was not effective in maintaining sperm integrity and viability after thawing and was toxic to spermatozoa at concentrations of 0.25 and 0.5%.

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.

Testicular shape and andrological aspects of young Nellore bulls under extensive farming

Aiming to determine the relationship between the frequency of testicular shape and the andrological aspects in young Nellore bulls, 18,676 animals were assessed. All andrological examinations were performed between the years 2000 and 2008. Animals were classified as able for breeding, able for breeding in natural mating system, unable for breeding and discarded. The testicular shape was classified as long, fairly long, oval-long, spherical-oval, and spherical. The analysis of Pearson correlations was performed for testicular shape with scrotal circumference, testicular volume, progressive motility, sperm vigor, major defects, minor defects and total defects. Testicles with oval shape prevailed (99.61%). It was obseved that 76.34; 66.34; 64.34; 58.33 and 50.00% of the animals were classified as sound for breeding for shapes long, fairly long, oval-long, spherical-oval, and spherical, respectively. Correlations between testicular shape with scrotal circumference, testicular volume, progressive motility, sperm vigor, major, minor and total defects were 0.26; 0.08; 0.00; 0.11; -0.02; 0.02 and -0.01, respectively. Testicular shape had no influence upon the andrological examination results. Testicles of long shape were prevalent within the population.

Avaliação de diferentes osmolaridades de soluções hiposmóticas e tempos de incubação no teste hiposmótico do sêmen de touros Nelore

The objective of this study was to evaluate different osmolarities and incubation times during the hiposmotic test and its correlation with cryopreservation of semen of Zebu bulls. It was used 30 ejaculates from six mature Nelore bulls. It was performed physical and morphological evaluation, supravital staining classification and hiposmotic test in the fresh semen. In the hiposmotic test, solutions with osmolarities of 60, 100, 150 mOsm/kg and distilled water (19 mOsm/kg) were used at 15, 30 and 60 minutes of incubation at 37oC. After cryopreservation, the samples were thawed and evaluated for hiposmotic test, supravital staining, slow termoresistance test and for fluorescent stain. No interactions were detected between incubation times and solution osmolarities. There were no differences in average values of reactive sperm incubated in different solutions with different osmolarities for frozen/thawed semen. Only the use of distilled water determined differences in the average values obtained in the hiposmotic test performed in fresh semen. There was no difference between the mean values of reactive spermatozoa incubated with different incubation time in both fresh and frozen/thawed semen. Hiposmotic test can be accomplished in 15 minutes of incubation time and with a solution which varies osmolarity from 60 to 150 mOsm/kg in both fresh and frozen/thawed semen.

Puberdade e maturidade sexual em touros jovens da raça Simental, criados sob regime extensivo em clima tropical

The objective of this study was to determine the age at puberty and sexual maturity and its relationship with body weight and testicular measurements in Simmental young bulls raised under pasture conditions in a tropical climate. Forty-four young bulls at 1 to 30 months of age were used. Body and testicular measurements were made monthly and ejaculates collected fortnightly, from six months of age by using the method of electroejaculation. Age at puberty was 13.42 ± 3.02 months and sexual maturity was observed at 21.43 ± 6.6 months of age, with body weight and scrotal circumference of 324.2 ± 23.7 kg and 26.90 ± 1.41 cm for puberty and 360 ± 69.04 kg and 34.88 ± 3.9 cm to sexual maturity, respectively. This study found late age to the timing of reproductive events, with direct relation to the type of management adopted.

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.

Can scrotal circumference-based selection discard bulls with good productive and reproductive potential?

Nonlinear mixed models were used to describe longitudinal scrotal circumference (SC) measurements of Nellore bulls. Models comparisons were based on Akaike’s information criterion, Bayesian information criterion, error sum of squares, adjusted R2 and percentage of convergence. Sequentially, the best model was used to compare the SC growth curve in bulls divergently classified according to SC at 18–21 months of age. For this, bulls were classified into five groups: SC < 28cm; 28cm ≤ SC < 30cm, 30cm ≤ SC < 32cm, 32cm ≤ SC < 34cm and SC ≥ 34cm. Michaelis-Menten model showed the best fit according to the mentioned criteria. In this model, β1 is the asymptotic SC value and β2 represents the time to half-final growth and may be related to sexual precocity. Parameters of the individual estimated growth curves were used to create a new dataset to evaluate the effect of the classification, farms, and year of birth on β1 and β2 parameters. Bulls of the largest SC group presented a larger predicted SC along all analyzed periods; nevertheless, smaller SC group showed predicted SC similar to intermediate SC groups (28cm ≤ SC < 32cm), around 1200 days of age. In this context, bulls classified as improper for reproduction at 18–21 months old can reach a similar condition to those considered as good condition. In terms of classification at 18–21 months, asymptotic SC was similar among groups, farms and years; however, β2 differed among groups indicating that differences in growth curves are related to sexual precocity. In summary, it seems that selection based on SC at too early ages may lead to discard bulls with suitable reproductive potential.

Behavioural and seminal characteristics of Santa Ines rams subjected to successive semen collections in the Amazonian region

The objective of this study was to evaluate the reproductive performance of Santa Ines rams subjected to successive semen collections in an Amazonian climate. Four rams were subjected to successive ejaculations during a maximum period of three hours. This procedure was repeated three times at 15-day intervals. Sexual and behavioural (libido) and andrological (testicular and seminal) assessments were performed. A total of 81 ejaculates were collected. Libido and semen vigour, volume, appearance and concentration decreased as the ejaculation frequency increased (P<0.05) and sperm motility showed a decreasing trend (P=0.06). The seminal pH increased over the sequence of collections (P<0.05). The only significant differences observed between individual rams were the variable scrotal circumference and the percentages of live sperm and sperm abnormalities (P<0.05). All the parameters of the first ejaculation were within the normal range for this species, which suggests that the local climatic conditions (high temperature and humidity) did not affect the behavioural, testicular or seminal parameters of experimental rams. Our findings indicate that the reproductive performance of Santa Ines rams could be affected by the intensification of ejaculation frequency; however, individual male variation needs to be taken into consideration.

Correlation between hypoosmotic swelling test and breeding soundness evaluation of adult Nelore bulls

This study aimed at evaluating the relationship between physical and morphological semen features with the hypoosmotic swelling (HOS) test in raw semen of adult Nelore bulls classified as sound and unsound for breeding. Two hundred and six Nelore bulls aging from 3 to 10 years of age were subjected to breeding soundness examination. After physical and morphological semen examination, HOS test was done. After the breeding soundness examination, 94.2% of the bulls were classified as sound for breeding. There was no difference between the average scrotal circumference of bulls classified as sound and unsound for breeding (P>0.05), but there was difference between all semen physical and morphological aspects of bulls classified as sound and unsound for breeding (P>0.05), and no difference resulted in the mean percentage of reactive spermatozoa to HOS test results both for sound (38.4±17.9) and unsound animals (39.5±16.4; P>0.05), with no Pearson correlation between the HOS test and variables. According to these results HOS test can not be used alone to predict the reproductive potential of adult Nelore bulls.