José Domingos Guimarães

Expression profile of genes associated with mastitis in dairy cattle

In order to characterize the expression of genes associated with immune response mechanisms to mastitis, we quantified the relative expression of the IL-2, IL-4, IL-6, IL-8, IL-10, IFN-γ and TNF- α genes in milk cells of healthy cows and cows with clinical mastitis. Total RNA was extracted from milk cells of six Black and White Holstein (BW) cows and six Gyr cows, including three animals with and three without mastitis per breed. Gene expression was analyzed by real-time PCR. IL-10 gene expression was higher in the group of BW and Gyr cows with mastitis compared to animals free of infection from both breeds (p < 0.05). It was also higher in BW Holstein animals with clinical mastitis (p < 0.001), but it was not significant when Gyr cows with and without mastitis were compared (0.05 < p < 0.10). Among healthy cows, BW Holstein animals tended to present a higher expression of all genes studied, with a significant difference for the IL-2 and IFN- γ genes (p < 0.001). For animals with mastitis no significant difference in gene expression was observed between the two breeds. These findings suggest that animals with mastitis develop a preferentially cell-mediated immune response. Further studies including larger samples are necessary to better characterize the gene expression profile in cows with mastitis.

Maturação sexual e parâmetros reprodutivos em touros da raça Nelore criados em sistema extensivo

The objective of this study was to verify the stage of sexual maturity, occurrence of the testicular format and the relationship among reproductive characteristics. Data were used from 5903 Nellore bulls averaging 21 months submitted to the soundness evaluation from 1999 to 2003. At the time of the evaluation, the following characteristics were recorded: scrotal circumference at soundness evaluation (31.99 ± 2.23 cm), left testicular length (11.21 ± 0.98 cm) and right testicular length (11.26 ± 0.97 cm), left testicular width (5.92 ± 0.44 cm) and right testicular width (5.97 ± 0.46 cm), testicular format (1.72 ± 0.46), testicular volume (632.21 ± 132.72 cm3), individual motility (69.56 ± 12.31%), vigor (2.87 ± 0.61), as well as total defects (22.19 ± 11.13%) and major defects (15.86 ± 10.45%) of the spermatozoa. The frequencies of the testicular formats were long (30.80%), long-moderate (66.19%), long-oval (2.49%), oval-spherical (0.02%) and spherical (0.04%). Correlations between the scrotal circumference and the reproductive traits were positive. Scrotal circumference is a good trait for selection of young Nellore bulls. More than 70% of the animals studied are sexually mature at 21 months old.

Eficiências Reprodutiva e Produtiva em Vacas das Raças Gir, Holandês e Cruzadas Holandês x Zebu

To evaluate the reproductive efficiency and its relationship with productive traits and genetic composition of a herd, in tropical climate, 113 cows were ssigned to seven crossbreeding levels: 1/2, 3/4, 7/8, 9/16 and 15/16 Holstein x Zebu, crossbreed pure Holstein and Gir. The studied traits were: age at calving, calving season, interval from calving to first service, interval from first service to fertile service, number of services, service period, interval calving, reproductive efficiency, lactation period, milk production by lactation order and genetic groups of the herd. Analyses of multiple regression, variance and comparison of averages using Tukey test were performed in statistical software SAEG. The reproductive efficiency was influenced by the age at calving, lactation period, calving interval and genetic composition of the cows, but it was not influenced by milk production and season. The productive indexes were not influenced by the calving season, but were influenced by the genetic composition of the animals. In this study, the reproductive indexes were satisfactory, the zebu cows presented the smallest productive indexes and the taurine ones the smallest reproductive efficiency, probably by larger sensibility to handling.

Sexual behavior and ejaculate characteristics in Pêga donkeys (Equus asinus) mounting estrous horse mares (Equus caballus)

The objectives were to (i) characterize sexual behavior of donkey stallions (jacks; Equus asinus) during on-farm semen collection using estrous horse mares (mares; Equus caballus); (ii) compare behavior of young (less experienced) versus older (more experienced) jacks; (iii) determine whether semen suitable for artificial insemination (AI) could be collected using mares; and (iv) determine the suitability of using mares in field collection of semen from jacks. Six Pêga jacks (3.5 to 16 yr old), previously conditioned to breed mares, were used. Mount mares were confirmed in estrus by a teaser horse stallion (stallion) and a jack. Semen was collected with an artificial vagina, at intervals of 48 to 72h (180 collections). The mean+/-SD (young [3.5 yr] vs. old [14 to 16 yr]) were Flehmen response frequency, 7.4+/-5.8 (8.1+/-3.0 vs. 7.0+/-2.0); number of mounts without erection, 1.1+/-1.3 (2.1+/-1.4 vs. 1.2+/-0.4, P<0.05); latency from first exposure to mare to full erection on the ejaculatory mount, 18.3+/-17.7min (25.3+/-21.3 vs. 12.2+/-6.2, P<0.05); latency from erection to insertion, 5.1+/-3.5sec (5.3+/-3.8 vs. 4.8+/-3.2); and duration of copulation from insertion to dismount after ejaculation, 25.4+/-7.8sec (22.1+/-2.9 vs. 28.1+/-9.3). In all jacks, sexual behavior was generally normal, with the notable absence of open mouth behavior. Mare estrous behavior was markedly less intense than that in the presence of a stallion and usually absent. Semen characteristics were gel free volume, 47.3+/-28.7mL; gel volume, 71.8+/-54.8mL; total motility, 84.3+/-6.0%; progressive motility, 74.3+/-74.5%; sperm vigor, 3.9+/-0.5 (scale 1 to 5); sperm concentration, 253x10(6) cells/mL; and total number of sperm, 10.3x10(9) cells. Copulation duration was significantly correlated with gel free volume (r=0.9) and gel volume (r=0.7). We concluded that (i) the sexual behavior of jacks during semen collection using mares was similar to that reported for natural mating to jennies, (ii) precopulatory and copulatory behavior for the young (less experienced) jacks and older (more experienced) jacks were generally similar (except number of mounts without erection and latency to full erection); (iii) semen obtained using mares as stimulus and mount females was similar to that reported with estrous jennies; and (iv) semen collection from previously conditioned jacks, using estrous mares, was appropriate for field collection of semen.

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%.

Hidratação enteral em equinos - solução eletrolítica associada ou não à glicose, à maltodextrina e ao sulfato de magnésio: resultados de laboratório

In the present study, the effects of four different electrolyte solutions on the packed cell volume (PCV), plasma volume and plasma concentrations of total protein, sodium, potassium, chloride, total magnesium, and ionized calcium in healthy and experimentally dehydrated horses were evaluated. Four crossbred horses, two males and two females were used. In experiment 1 (E1Des) the animals were experimentally dehydrated, while in the second experiment (E2Hig) healthy equines were used. In both experiments the animals were subjected to the following treatments: SE - isotonic electrolyte solution; SEGlu - glucose-enriched SE; SEMalt - maltodextrine-enriched SE and SEMg - magnesium sulphate-enriched SE. The electrolyte solutions used in all treatments were administered at 15mL kg-1 h-1 during 12h through small-bore nasoesophagus tube by continuous flow. The treatments with the electrolyte solutions resulted in an increase of plasma volume and a decrease in total plasma protein, hematocrit, while the electrolytes remained within the reference values.

Potencial reprodutivo de touros da raça Nelore submetidos a diferentes proporções touro: vaca

This study evaluated the reproductive potential of 20 Nelore bulls, submitted to different bull:cow ratio. Correlations among the serum testosterone concentration, scrotal circumference, sperm quality and libido were also estimated. The bulls selected by andrologic evaluation and the libido test were alloted to the following bull:cow ratio (treatments): 1:25 (T1), 1:50 (T2), 1:75 (T3) e 1:100 (T4), with five replicates per treatment. Blood samples were collected to determine serum testosterone concentration. Semen physical and morphologic characteristics, scrotal circumference and libido of the bulls did not differ among treatments. The pregnancy rate of the cows was not affected by treatments (means of 42.1, 66.5 and 71.0 % for breeding season of 30, 60 and 90 days, respectively). The testosterone concentration was not affected by treatments and the mean serum testosterone concentration was 4.04ng/ml, which peaked at 9am. The correlations between the libido, semen physical and morphologic characteristics, and the scrotal circumference of the bulls were low. Nelore bulls with good sperm quality and libido supported a large number of cows, and the bull:cow ratio of 1:100 did not reduce the pregnancy rate.

Use of complementary tests to evaluate the freezing ability of semen from goats under artificial photoperiod exposure

O congelamento do semen de bodes das racas Alpina e Saanen submetidos ao manejo de fotoperiodo artificial foi avaliado por meio dos testes de termorresistencia (TTR), hiposmotico (HOST) e de integridade do acrossoma. Foram utilizados oito machos caprinos (quatro da raca Alpina e quatro da raca Saanen) de duas idades diferentes (jovens e adultos). A qualidade do semen durante as etapas do congelamento foi superior em bodes jovens de ambas as racas. Avaliada pelo TTR, a motilidade do semen fresco apresentou longevidade pos-descongelamento. Os resultados de motilidade espermatica, obtidos imediatamente apos o descongelamento, tiveram reflexos positivos sobre o TTR, indicando que os semens que apresentaram maior motilidade pos-coleta (86,2% vs 79,3%) e pos-descongelamento (37,7% vs 32,0%) tiveram maior longevidade seminal. Os resultados do HOST, tanto para o semen fresco quanto para o congelado, nao diferiram entre racas e idades. Houve reducao na porcentagem de espermatozoides integros apos o congelamento e descongelamento do semen dos animais da raca Alpina e dos adultos Saanen. Houve reducao superior a 14% nos valores do HOST para o semen congelado em relacao aos valores observados para o semen fresco (38,0 vs 52,0%, respectivamente). A motilidade espermatica progressiva mostrou maior sensibilidade a criopreservacao que a integridade da membrana espermatica, indicando que a motilidade espermatica e mais afetada pelo processo de congelamento que a membrana plasmatica. A integridade do acrossoma nao foi influenciada pelo descongelamento. Os indices de danos acrossomais (edema, desprendimento parcial e ate perda total de acrossoma) mostraram-se dentro do padrao aceitavel (44,5%), tanto no pos-descongelamento como apos o termino do TTR.

Dinâmica folicular em cabras da raça Toggenburg em lactação tratadas ou não com somatotropina bovina recombinante

The effect of the r-bST injection was evaluated on the goats estrous cycles. Twenty-four Toggenburg does were used in two treatments: T1 (n=12) treated with r-bST; and T2 (n=12) treated with saline solution (control). After the first r-bST injection, the estrous cycles were checked between two estrus. The estrous cycle length and interovulatory period of the goats did not differ between treatments (P>0.05). Estrous cycles with two, three and four waves of follicular growth were observed. The number of waves during the estrous cycle were not affected by the r-bST treatment (P>0.05). The number of 3mm follicles was different between T1 and T2 (P 0.05) between treatments. The r-bST did not affect the ovarian response during the estrous cycle. The r-bST not affected the follicular dynamic of Toggenburg lactating does, but increased the number of emerging follicles ≥3mm during the estrous cycle.

Avaliação andrológica por pontos e comportamento sexual em touros da raça Nelore

The objective of this work was to study the relation between two reproductive potential evaluation methods - Andrologic Evaluation by Points - CAP and sexual behavior of Nelore bulls, and to verify the accuracy of these tests in predicting the reproductive potential of bulls through the gestation rate at the end of the breeding season, with average duration of ninety days. Fourteen bulls were used, all classified as able for reproduction, evaluated through andrologic examination, being submitted to CAP and observation of the sexual behavior at field (libido test) during 12 hours. Eleven bulls were evaluated in individual handling, with an average bull:cow ratio of 1:46 and the rest of the animals (three), evaluated in a multiple handling, with an average bull:cow ratio of 1:23. The average score obtained by CAP was 78.92 ± 8.92 (very good) and the score of 9.85 ± 0.36 (excellent) for the libido test. The longer the test was, the higher libido scores were obtained. At the first time of observation, the bulls were classified as with questionable libido and at the end of the test as with excellent libido. The correlations between libido, scrotal circumference (SC), physical and morphological characteristics of the semen and the gestation rate were low. The scores obtained through CAP was positively correlated with SC and physical characteristics of the semen; however, no correlation was observed for the morphologic characteristics. No correlation was observed between CAP and gestation rate or between libido and CAP. The overall gestation rate after the breeding period was 74.69%. The results suggest that both CAP and the libido test were not efficient to predict the reproductive potential of Nelore bulls and should be used as a complement to the andrologic evaluation.