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The objective of this study was to estimate the prevalence of and risk factors for pathological conditions of the reproductive organs in stray dogs under tropical conditions. Three hundred and eighteen dogs were examined post-mortem in the period from 1 July 2002 to 30 June 2003. Before killing, a blood sample (from the cephalic vein) for testosterone assay was taken. Pathological conditions of the reproductive organs were found in 135 of the dogs (42.5%) and in 175 of the testes (64.8%). The most frequent pathologies found were testicular degeneration, cryptorchidism, testicular hypoplasia and testicular tumours (in 15.1%, 6.6%, 6.6% and 5.4% of the dogs and 15.1, 4.6, 6.0 and 3.5 of the testes, respectively). Transmissible venereal tumour (TVT) was seen in 5.4% of the dogs. Testicular degeneration was more common in old dogs and underweight dogs (p < 0.05). Testicular tumours were 14.3 times more common in cryptorchid dogs. Age was another important factor for the development of testicular tumours (p < 0.05). Lower levels of testosterone concentration (p < 0.05) were observed in dogs with advanced testicular degeneration (0.7 +/- 0.8 nM), dogs with hypoplastic testicles (0.8 +/- 0.9 nM) and dogs with one degenerated and one retained testis or with bilateral cryptorchidism (1.2 +/- 0.9 nM) compared to dogs with one or two normal testes (7.0 +/- 5.5 nM). Testicular volume and weight were significantly lower in degenerated, hypoplastic and retained testes compared with the contralateral normal testis. Some spermatogenic activity was found in three of the retained testes, producing oligozoospermic smears with a high percentage of sperm abnormalities. No comparable epidemiological data about male pathological conditions of the reproductive organs in the dog is available. The prevalence found in this study, yet, appears high.

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Bovine herpesvirus 1 (BoHV-1) and bovine viral diarrhea virus (BVDV) are well known etiological agents of cattle that produce important economic losses due to reproductive failures and calf mortality, as well as enteric and respiratory disease. Tamaulipas is located northeast of Mexico, an important cattle production and the principal exporter of calf and heifer to the United States. The objectives of this study were to estimate the seroprevalence of BoHV-1 and of BVDV, and to determine the effects of risk factors on these infections. Blood samples of cattle from 57 farms from rural districts of Tamaulipas were collected. The samples were tested for antibodies against BoHV-1 and BVDV using commercial ELISA kits. Data on potential risk factors were obtained using a questionnaire administered to the farmer at the time the blood samples were taken. The seroprevalences for BoHV-1 and BVDV were 64.4% and 47.8%, respectively. In the logistic regression analysis, the significant risk factors were rural district, herd size and cattle introduced to the farm. This study confirms the high seroprevalence of BoHV-1 and BVDV in unvaccinated cattle in Tamaulipas, Mexico. The results of this study could be used for the development of BoHV-1 and BVDV prevention and control program in North-Eastern, Mexico.

The objective was to evaluate the reproductive performance and productivity of Pelibuey ewes in two flocks in Southeastern Mexico. Animals grazed on irrigated star grass (Cynodon plectostachyus). In flock 1, lambs grazed with their mothers from 7 to 70 days of age (weaning age), whereas in flock 2, they were confined and offered chopped grass, a commercial concentrated and managed under restricted suckling until weaning at 60 days of age.. The statistical model included the fixed effects of flock, year and season of lambing, parity number, litter size at weaning, first order interactions and the random effects of ewe and the error term. The means ± SD for age at first lambing, prolificacy, lambing interval (LI), weaning weight, and productivity were 477 ± 85.5 days, 1.41 ± 0.51 lambs, 255.9 ± 51.8 days, 16.5 ± 4 kg, and 18.1 ± 4.42 kg of lamb weaned, respectively. Repeatability estimates for the latter four traits were 0.09, 0.07, 0.11, and 0.13, respectively. All main effects in the models were significant (P < 0.001), except for year on LI. Prolificacy and productivity increased with parity number. The shortest LI was in the rainy season. Ewes with two or three lambs produced 8 and 14 kg of lamb more at weaning than single lamb ewes. In conclusion, reproductive performance and productivity could be improved, and the low repeatability estimates suggest that management should be used in a short term rather than genetic approaches.

The objective of this study was to estimate the prevalence and identify risk factors associated with the presence of Toxoplasma gondii in pig-fattening farms from Yucatan, Mexico. A cross-sectional study was conducted with a two-stage sampling. There were 429 pigs sampled from 39 farms randomly selected. Blood samples were collected to obtain DNA and serum. The presence of IgM and IgG antibodies was determined by indirect ELISA. Prevalence was estimated by diagnostic test. Potential risk factors to be included in a marginal logistic regression were tested by chi-square or Fisher. The prevalence of IgM and IgG was 92.5% (397/429) (CI 89.9–95.1%) and 95.8% (411/429) (CI 93.7–97.8%), respectively. Regarding PCR, a prevalence of 50.8% (218/429) (CI 45.9–55.6%) was found. The logistic regression showed an association with herd size and type of feeder (P < 0.05). The risk of a case in farms with ≤400 pigs was 27.9 times higher than in farms with >400 pigs. The manual feeder was a significant protective factor associated with the seropositive against T. gondii. Results indicate a high circulation of T. gondii in pig-fattening farms from Yucatan, finding an increased risk of infection for those farms with less than 400 animals and automatic feeders.

The genetic parameters for Brahman cattle under the tropical conditions of Mexico are scarce. Therefore, heritabilities, additive direct and maternal correlations, and genetic correlations for birth weight (BW) and 205 days adjusted weaning weight (WW205) were estimated in four Brahman cattle herds in Yucatan, Mexico. Parameters were estimated fitting a bivariate animal model, with 4,531 animals in the relationship matrix, of which 2,905 had BW and 2,264 had WW205. The number of sires and dams identified for both traits were 122 and 962, respectively. Direct heritability estimates for BW and WW205 were 0.41 ± 0.09 and 0.43 ± 0.09, and maternal heritabilities were 0.15 ± 0.07 and 0.38 ± 0.08, respectively. Genetic correlations between direct additive and maternal genetic effects for BW and WW205 were -0.41 ± 0.22 and -0.50 ± 0.15, respectively. The direct genetic, maternal, and phenotypic correlations between BW and WW205 were 0.77 ± 0.09, 0.61 ± 0.18, and 0.35, respectively. The moderate to high genetic parameter estimates suggest that genetic improvement by selection is possible for those traits. The maternal effects and their correlation with direct effects should be taken into account to reduce bias in genetic evaluations.

The objective of this study was to estimate the seroprevalence of anti- Toxoplasma gondii antibodies and DNA of women with spontaneous abortions in 2 hospitals located in Yucatan, Mexico. Between June 2008 and May 2009, blood samples were taken from 100 women with spontaneous abortion attending the Ticul City Communitarian Hospital and the Merida Mother-Kid Hospital. The sera were tested for anti- T. gondii IgG and IgM antibodies. Blood samples (5 ml with anticlotting agent) were also used for polymerase chain reaction (PCR) assay, to detect T. gondii DNA. Forty-two of the 100 samples were negative. Of the positive samples (n = 58), 32 were positive to IgG, 2 to IgM, 5 to IgG and IgM, 6 to IgG and PCR, 1 to IgM and PCR, and 12 to IgG, IgM, and PCR. Accordingly, 55% of the women were seropositive to at least IgG, 20% to at least IgM, and 19% via PCR. Differences between hospitals were significant (P < 0.05) only for IgM. The risk of infection (IgM positive) was 2.85 (odds ratio [OR] 95%, confidence interval [CI]; 1.03-7.87) times greater in women patients at the Merida Mother-Kid Hospital, than those at the Ticul Communitarian Hospital. More studies are needed to evaluate the impact of this disease and to establish strategies to follow in order to reduce congenital toxoplasmosis in the populations at risk.