The objective of this study was to reduce the level of the biological marker Cr2O3 in animal diets, due to the sensibility of the sdiphenylcarbazide spectrophotometric method for chromium determination in feces, recently developed. Six levels of marker, chromium (III) oxide (0.01% – 0.02% – 0.03% – 0.05% – 0.1% and 0.2%), were incorporated into isoproteic and isoenergetic diets, for the apparent digestibility assay of the “piauçu” (Leporinus macrocephalus), in a design of entirely randomized groups. Feces were collected during […]

This work aimed to evaluate different crude fiber levels on reverted Nile tilapia (Oreochromis niloticus, L) fingerlings performance and time of retention of food. One hundred and twenty-five fingerlings of Thai strain, 1.39 ± 0.03 g of initial weight were allotted to twenty-five 54 L aquarium, at five treatments and five replications on completely randomized design. Five isoenergy (3000 kcal/kg of digestible energy) and isoprotein (30% of crude protein) diets were formulated with five different crude fiber levels (3.65, 4.75, […]

This work was carried out at Aquicultura Laboratory of Maringá State University, to evaluate the different processing form of diets on Nile tilapia fry performance and survive, during sexual revert phase. Was utilized 540 fry distributed, on completely randomized design with three treatments and six replications, in eighteen 54 L aquarium and one aquarium with 30 Nile tilapia fry was considered an experimental unit. The experimental period was 28 days with average temperatures of 21.9 ± 0.1ºC in the morning […]

This work was carried out to evaluate the influence of water tensions (35, 60, 100 and 500 kPa) and nitrogen levels (0 – Control, 45, 90, 180, 360 kg/ha) on the dry matter (DM) yield, the dry matter yield rate (DMYR) and the leaf area index (LAI) of Cynodon spp. cv. Tifton 85 bermudagrass. A randomized blocks design in a split splot scheme with three replications was used, split plots were represented by the water tensions were and the plots, […]

The follicular dynamics and luteal regression were studied in 12 Gir and seven Nelore cows, treated with prostaglandin F2a analog, between days 10 and 12 of the estrous cycle. The synchronization rate was higher than 92% for the Gir and Nelore cows, and the ovulation of the second dominant follicle occurred in 72.7% of the Gir and all the Nelore cows. The Nelore ovulatory follicle diameter was lower than Gir cows ((11.0 ± 0.9 mm x 13.0 ± 1.7 mm). […]

Genetic parameters for first lactation test-day milk yields and 305 day milk yield (M305) for Caracu cows were estimated. The test-day animal model included additive genetic effect as random and contemporary group and age of cow (quadratic regression) as fixed effects. Two contemporary groups were defined to explain variation, composed by year, week of test and paddock (gc1) or year, week of test and paddock (gc2). Variance components were estimated by Restricted Maximum Likelihood. Phenotypic, residual and genetic additive variances […]

153,963 test day milk yield records and 13,273 first lactations of Holstein cows calving between 1989 and 1998, were used with the objective of estimating genetic, phenotypic and environmental parameters for test day milk yield (PLDC) and 305 day milk yield (P305) and to study the convenience of using test day yields in genetic evaluations to replace P305. Four models were used. Models 1 and 2 differed according contemporary grouping and monthly milk records were considered as repeated measures. In […]

The economic values of dairy cattle were derived from economics and production data of a demonstration farm, the “Pasture Dairy Production System using Holstein Zebu Cattle” at Embrapa-Dairy Cattle. The economic values were estimated by two methods 1) from the partial derivative of profit with respect to each trait, and 2) from the partial derivative of the income/cost ratio, both evaluated at the mean value of all other traits. With the latter method, the economic values of traits considered, expressed […]

The objective was to evaluate the effect of temporary mother-litter separation on the reproductive performance of lactating does and growth performance of their litters up to 70 days of age. A total of 415 presentations of 157 lactating does assigned to two groups: control, with free nest access, and treated, whose nest access was closed during the 39 hours that preceded mating, were analyzed. From the 415 presentations, 387 resulted in matings and 264 in parturitions. Does of the treated […]

Records on 6,674 Nellore cattle weight, born from 1975 to 1990 in two farms located in Paraiba State were used to study environmental effects and to estimate genetic parameters for average daily gains from birth to 205 days, from 205 to 365 days and from 365 to 550 days. The SAS® program was used to study the environmental effects. The model included the random effect of sire and the fixed effects of year-month-sex, farm and age of the cow at […]