Association of CAPN1 316, CAPN1 4751 and TG5 markers with bovine meat quality traits in Mexico.

We examined allele and genotype frequencies for the molecular markers CAPN1 316, CAPN1 4751 and TG5, and determined whether they are associated with beef quality traits in Mexican cattle. One hundred and twenty-four longissimus dorsi muscle samples were collected from cattle from north, central and southern Mexico. CAPN1 316 and CAPN1 4751 frequencies were determined using the allelic discrimination assay and the TG5 marker was typed by PCR-RFLP. Meat quality traits included intramuscular fat content (IMF) and tenderness determined by Warner-Bratzler shear force (WBSF) at 24 h postmortem. The association test was made using a mixed model, including genotypes, genetic group, and sampling location as fixed effects. Least squares means and significant interactions were compared using least significant differences based on the mixed procedure. CAPN1 316 CC was found at a low frequency (0.03) and has been reported as a favorable genotype associated with tenderness meat. Genotype frequencies for CAPN1 4751 were similar in favorable (CC) and unfavorable (TT) genotypes (0.26 and 0.28, respectively). The TG5 CC genotype had a frequency of 0.73, while the TT genotype frequency was 0.01. The means for WBSF and IMF were 4.08 ± 1.35 kg and 5.23 ± 2.14%, respectively. Sampling site and the CAPN1 316 genotypes significantly affected WBSF (P < 0.05). Samples collected from Hermosillo, Sonora, had the lowest WBSF (P < 0.05), while those collected in Veracruz were toughest (WBSF = 5.267 kg). The effect of GG and TG5 genotypes on IMF was significant (P < 0.05). CAPN1 316 and TG5 markers were found to be significantly associated with beef quality traits and thus will be useful for Mexican beef characterization.

Integrating the issues of global animal and public health into the veterinary education curriculum: a Latin American perspective.

This paper describes the development of a consensus profile for the Latin American veterinarian, and its adoption as the basis for curricular change by veterinary schools in the region. The process has been conducted by three Pan American organisations: the Pan American Association of Veterinary Science, the Pan American Federation of Veterinary Schools, and the Pan American Council of Veterinary Education, with strong backing bythe Food and Agriculture Organization of the United Nations. Recommendations for curricular harmonisation have been issued that will facilitate student and academic exchanges and, above all, will guarantee that the graduates from participating colleges have the knowledge, competencies and skills to adequately perform in the different fields of veterinary medicine, including those most relevant to global animal and public health.

Reproductive activity of Pelibuey and Suffolk ewes at 19 degrees north latitude.

Under photoperiod regulated conditions, some Pelibuey ewes appear to express estrous cycles continuously throughout the year. Ovulatory activity of Suffolk ewes has not being determined at 19 degrees N. The aim of the present study was to describe the annual reproductive cycle of Pelibuey and Suffolk ewes under natural conditions at 19 degrees N. Ten adult ewes of each breed were maintained under natural environmental conditions, on a constant plane of nutrition and isolated from rams. The ovulatory activity of both breeds was monitored over 2 years (2003 and 2004) by quantifying progesterone concentrations in blood samples taken twice a week. For both breeds, the proportion of ovulating ewes per month and year was analyzed by chi(2). The duration of anestrus was compared between breeds and years by analysis of variance. Correlation of ambient temperature and weight changes with the ovulatory activity was evaluated by regression procedure. Ovulatory activity was different (P<0.05) between breeds from February to July. Pelibuey sheep (60%, 6 of 10) ovulated continuously during the entire study; one animal was eliminated in the second year, due to ovarian follicular cysts and three ewes had anestrous periods from 65+/-46 to 70+/-36 days. Suffolk ewes displayed reproductive seasonality similar to that observed in sheep of the same breed in latitudes greater than 35 degrees . Within breed, reproductive behavior of sheep was similar between years, with the only difference (P<0.05) observed in February for Pelibuey and in July for Suffolk relative to other months. Ambient temperature was not correlated with ovulatory activity. The body weight of Pelibuey ewes was constant during the entire study and was not correlated with ovulatory activity. There was, however, an increase on the body weight of Suffolk ewes, but this variation was not related to ovulatory activity. These findings lead to the conclusion that at 19 degrees N, a high proportion of Pelibuey ewes is capable of ovulating throughout the year, whereas Suffolk ewes undergo seasonal anestrous periods similar to those observed in individuals of the same breed at latitudes greater than 35 degrees . Identification of continuous ovulatory Pelibuey ewes may be the first step for developing a selection program against seasonality to increase lambing frequency.

A survey of beef carcass quality and quantity attributes in Mexico.

The objective of the present study was to evaluate quality and yield attributes of Mexican beef carcasses to serve as a benchmark for production in the Mexican beef cattle industry. Seven packing plants were surveyed nationwide. Carcass yield and quality traits were assessed in the cooler at approximately 24 h postmortem. Results indicated that around 90% of the beef slaughter population in Mexico has a strong Bos indicus genetic background. Moreover, 71.6% of the surveyed cattle are presented for slaughter at a BW between 400 and 500 kg. Chilled carcass weight was between 220 and 340 kg in 88.9% of the surveyed population. According to European beef carcass grading standards, carcass conformation varied from poor to good in 82% of the carcasses, whereas in 17.8% the conformation was very good or excellent. In 60.7% of the surveyed carcasses the KPH was 2% or less. The subcutaneous fat depth was 1 cm or less in 90% of the carcasses. In 71.8% of the carcasses the LMA was of 80 cm(2) or less, whereas only 8.6% had LMA values of 90 cm(2) or greater. Carcass maturity score USDA B(100) or less was found in 92.4% of the evaluated carcasses, whereas 28.5% were graded as USDA A(100)/B(00). A total of 93.6% of the sample had marbling scores of 300 or less, corresponding to the categories slight, practically devoid, or traces. Only 12.9% of the carcasses exhibited a yellow fat cover. In the remaining 87.1% the fat cover was white or beige. The backfat layer was uniform in 43.2% of the carcasses, whereas 55.9% had an uneven fat cover. Information from this survey provided data that could serve as a means to develop a yield and quality evaluation program that can be further developed into a value system for Mexican beef carcasses and live cattle.