The aims of this research were to determine economic selection indices in order to reach the target objective for a Caracu cattle nucleus. The breeding objective (H) considered a dual purpose breed producing milk and weaning calves. The biological traits affecting income and expenses considered in H were: total milk yield, age at first calving, number of days open, weaning weight, and productive lifetime. Two economic selection indices were calculated. The selection criteria included in Index 1 were first lactation […]

Two different preweaning selection criteria in Gyr cattle: average daily gain from birth to weaning (ADG) and number of days to gain 160 kg from birth to weaning (D160) were evaluated in this study. Records from the Brazilian Zebu Breeders Association obtained from 1978 to 1994, were studied. (Co)variance components and heritabilities were estimated by restricted maximum likelihood derivative free method, and expected breeding values (EBV) were predicted using an single trait animal model. In the model, contemporary group was […]

A data set with 16,592 records from the Brazilian Zebu Breeders Association obtained from 1978 to 1994, was used to estimate genetic parameters for preweaning average daily gain (ADG) and number of days to gain 160 kg (D160) in Gyr cattle. The (co)variance components and heritabilities were estimated by the restricted maximum likelihood derivative free method. Two models were used: the first one considered contemporary group (CG) as fixed effect and additive direct and maternal genetic effects, maternal permanent environment […]

Covariance components for test day records and lactation milk yield using 263.390 records of 32.448 first lactation Holstein cows, were estimated using animal models by REML. Besides the lactation model, two alternative repeatability models (RM) were analyzed. Lactation model included fixed effects of herd-year-season and age of cow with linear and quadratic terms, and random effects of animal and error. The first model for test-day yield (RMF) included the same effects, but fixed effect of contemporary group, defined as herd-year-month […]

The properties of seven nonlinear models were discussed concerning its applications in the fitting of growth curves in animal production. The models used: Brody, Richards, Von Bertalanffy and two alternatives of Gompertz and Logistic models, were fitted by Gauss Newton method to weight-age data from eight animal species: freshwater prawn Macrobrachium rosenbergi, pepper frog, rabbit, poultry, sheep, goat, swine and cattle. Considering results of the fitted models such as convergence or not, coefficient of determination and biological interpretation of parameters, […]

An experiment was carried out under controlled conditions at the Embrapa Dairy Cattle, Juiz de Fora, MG, aiming to study the efficiency of two commercial inoculants of Rhizobium meliloti on the development of alfalfa cultivars in a “;cerrado”; soil classified as Dark-Red Latossol (Oxisol). The experimental design was a randomized blocks, in a 3 x 4 factorial, with four replications and the following treatments: a) three alfalfa cultivars: Crioula, Crioula CNPGL and P30; b) two commercial inoculants and two checks […]

The effect of different pasture structures imposed by treatments of green leaf lamina biomass (GLLB) levels of 350 and 600 kg/ha of dry matter (MS), over animals grazing behaviour was evaluated in this experiment. The pasture was oat (Avena strigosa Schreb.) and Italian ryegrass (Lolium multiflorum Lam.). Animals activities were recorded in August and September, in 24 consecutive hours, by trained observers. In the hours of the day in which grazing were more intense, grazing stations remaining time, distance between […]

This study aimed to evaluate the tolerance of four Brachiaria species (B. decumbens,B. brizantha, B. humidicola and B. mutica) to flooding with regard to their morphogenetical, physiological and production characteristics. The experimental treatments resulted from a 4 x 3 factorial arrangement of four Brachiaria species and three flooding conditions (water field capacity, 1 and 10 cm water lamina above the soil surface) distributed in a completely randomized block design, with three replications. The experiment was carried out in greenhouse, in […]

Two experiments were carried out from December/1997 to June/1998. One experiment was performed on hilly area e and the second one on lowland area. These experiments aimed to evaluate the tolerance to flooding and low soil water potential of three commercial Brachiaria species (B. decumbens cv. Basilisk, B. brizantha cv. Marandu e B. mutica) and three acesses (B. brizantha B-11, B. humidicola cv. Tupi and B. dictyoneura). Morphogenetical, productive and plant water status were the variables assessed. In each experiment […]

This study aimed to evaluate the tolerance of Brachiaria species (B. decumbens, B. brizantha, B. humidicola and B. mutica) to low soil water potential. Morphogenetical, physiological and production characteristics were estimated during and after the stress period. The experimental treatments resulted from 4 x 5 factorial arrangement consisting of four Brachiaria species and five soil water potential (-0, 01; -0, 03; -0, 1; -0, 5 and -1, 5MPa) distributed in randomized block design, with three replications. The experiment was carried […]