Variation in rectal and skin temperature of pantaneira and nelore cows and calves in the pantanal

The Pantanal region of Brazil has an inhospitable environment and highly variable climatic conditions. Animal productivity depends on the animal¿s ability to dissipate heat efficiently. The Pantaneiro (Bos taurus) and Nelore (Bos indicus) are cattle breeds that are considered adapted to these conditions. Nevertheless there are few studies showing heat tolerance of these breeds in the region. This work aims to evaluate body and skin temperatures of cows and calves of these two cattle breeds during an extremely dry year in the sub region of Nhecolândia, Pantanal. Lactating cows of the Pantaneira and Nelore, with suckling calves, raised during the same season were evaluated in November 2002 until October 2003. These animals were measured monthly for skin and body temperature and environment temperature and relative humidity of the air were also measured as the animal went through the stall. During the study period, environmental temperature varied from 22 to 43°C and relative humidity from 22 to 100 percent. Rectal temperature was influenced by environmental temperature and skin temperature. The mean rectal temperature for cows was 37.9±1.0°C and 38.1±1.7°C and calves was 39.3±0.6°C and 40.0±0.8°C for the Pantaneira and Nelore breeds, respectively. Skin temperature for the cows was 33.6±3.8°C and 32.9±3.3°C and for calves was 34.2±3.5°C and 35.6±3.2°C for the Pantaneira and Nelore breeds, respectively. The Pantaneira cows had lower rectal and skin temperatures than Nelore, and vice versa for the calves. Rectal and skin temperatures were lower in cows than calves for both breeds. Skin temperature had a high negative correlation with relative humidity for both breeds, where lower values were expected in the rainy season. This probably did not happen as there was an extreme dry season during this period. Generally, the values found for rectal and skin temperatures show thee two breeds to be adapted to conditions in the Pantanal

Effect of breed and corpus luteum on pregnancy rate of bovine embryo recipients

The objective of this study was to evaluate pregnancy rates of recipients of different breed groups (Nellore and crossbreed), as well as the effects of size and type of the corpus luteum (CL) on plasmatic concentrations of progesterone and pregnancy rates of embryo recipients. A total of 152 heifers were synchronized with progesterone implants and on the day of embryo transfer, previously obtained by superovulation and frozen in ethylene glycol, the diameter and type of the corpus luteum (cavitary and compact) was measured and blood was collected for progesterone measurement. The pregnancy rate was 44.1%, with a diameter of corpus luteum higher in recipients that became pregnant (2.03±0.41) compared with non-pregnant ones (1.86±0.34 cm). Plasmatic concentrations of progesterone did not differ between pregnant (1.50±1.05) and non-pregnant (1.31±0.91 ng/mL) animals. The type of corpus luteum did not influence the pregnancy rates. Only Angus and crossbred Marchigiana differ among themselves in pregnancy rates (33.3 and 59.2%, respectively). The pregnancy probability was affected only by CL diameter, but not by P4 plasmatic concentration. Selection of the corpus luteum size at the time of embryo transfer is an important factor to increase pregnancy rates in recipients, and compact and cavitary corpora lutea do not influence the pregnancy rates of bovine embryo recipients. Nellore recipients have pregnancy rates that are satisfactory and comparable to crossbred (Bos taurus × Bos indicus) recipients