Mexican Creole chickens: effect of data collection periods on goodness-of-fit and parameter precision of growth models.

The objective of this study was to estimate the good-of-fitness and precision of parameters of the Gompertz-Laird, Logistic, Richards, and Von Bertalanffy growth models, using different data collection periods (DCP). Two hundred and sixty-two Mexican Creole chicks (116 females and 146 males), were individually weighed to form the following sets of data for each sex: DCP (weights recorded weekly from hatching to 63 d, and every 2 wk, from 63 to 133 d of age), DCP (weights recorded weekly from hatching to 133 d of age), DCP (weights recorded every third day, from hatching to 63 d, and every 14 d, from 63 to 133 d of age), and DCP (weights recorded every third day, from hatching to 63 d, and weekly, from 63 to 133 d of age). Data were analyzed using the NLIN procedure of SAS (Marquardt algorithm).

Productive performance of Mexican Creole chickens from hatching to 12 weeks of age fed diets with different concentrations of metabolizable energy and crude protein.

Objective: The study aimed to evaluate the productive performance, carcass yield, size of digestive organs and nutrient utilization in Mexican Creole chickens, using four diets with different concentrations of metabolizable energy (ME, kcal/kg) and crude protein (CP, %).

Methods: Two hundred thirty-six chickens, coming from eight incubation batches, were randomly distributed to four experimental diets with the following ME/CP ratios: 3,000/20, 2,850/19, 2,700/18 and 2,550/17. Each diet was evaluated with 59 birds from hatching to 12 weeks of age.

Relation of the maximum temperature and relative humidity close to the insemination with the tropical milking criollo heifer's gestation in three seasons.

The high climatic variability of hot climates of the intertropical zone reduces cattle fertility. In dairy cows in temperates zones, the THI has been used to evaluate the temperature and relative humidity (RH) joint effect in reproduction, but its use is not recommended in all geographic zones; in hot climates, the maximum temperature (Tmax) can provide more convenient information than THI. The objective of this study was to determine the artificial insemination (AI) service seasons and their joint effect with the maximum temperature and relative humidity of the previous seven days, the service day, and posterior seven days to the AI in the tropical milking criollo (LT) heifer's gestation.

Detection of subsp. in reproductive tissue and semen of naturally infected rams.

subsp. (MAP) is the causative agent of paratuberculosis (PTB), disease that causes a syndrome of bad nutrient absorption, weight loss and eventually death. The intestine is the main target organ where the infection develops; however, there is evidence of infection by MAP in extra-intestine sites of sheep, including mesenteric nodes and semen.

Soybean meal substitution by dehulled lupine (Lupinus angustifolius) with enzymes in broiler diets.

Objective: Evaluate the effects of i) dehulling of lupine seed on chemical composition and apparent metabolizable energy (AME) and ii) soybean meal substitution by dehulled lupine seed in broiler diets with enzymes on productive performance, size of digestive organs and welfare-related variables.

Methods: Experiment 1, chemical composition and AME were determined in whole and dehulled lupine seed. Experiment 2, two hundred eighty-eight one-day-old male Ross 308 broilers were used.

Biological activity of Claviceps gigantea in juvenile New Zealand rabbits.

The Ascomycete fungus Claviceps gigantea infects maize kernels and synthetizes several alkaloids, mostly dihydrolysergamides. There is limited information on the damage these toxins cause in mammals, despite reports from infested areas with 90% presence of the fungus sclerotia. With this background, it was decided to determine the biological activity of chemical compounds present in sclerotia of C.