The objective of this study was to estimate the genetic correlation between semen (semen volume, sperm motility and spermatozoa concentration) and egg production traits (partial and total egg production, and egg weight) from a White Leghorn strain. In order to obtain semen traits, 698 DD1 strain roosters developed at CNPSA/EMBRAPA were used. The semen were collected at 24, 26 and 28 wk of age, and, to obtain the egg traits, full sisters (average of two sisters per male) were used. […]

This study investigated the effect of semen extender on in vitro development of bovine oocytes after in vitro maturation and fertilization. The ejaculate from one bull was divided in three parts which were diluted with three different extenders: Egg yolk/Lactose (EYL), Egg yolk/Citrate (EYC) and Egg yolk/Tris (EYT). Samples of semen diluted with these extenders were frozen in liquid nitrogen and, after thawing, were filtered by discontinuous Percoll gradient. The sperm concentration was adjusted to 10 x 106 cells/mL and […]

The objective of this study was to evaluate the indirect effects of selection for post-weaning weight on body measures and scrotal perimeter of 809 Nellore males from selected herds (NeS and NeT) and control herd (NeC), of the Estação Experimental de Zootecnia de Sertãozinho. The statistical analyses were performed by using a sire mixed model where the random source of variation, sires, was nested within herds. The fixed effects were herds, year of performance test (PGP), age of cow and […]

To evaluate the effect of a hiperlipidemic diet on the reproductive performance, lipidic metabolites and serum progesterone levels, 42 Holstein-Zebu crossbred cows were submitted to two treatments: T1 (n=21), control diet, and T2 (n=21), hyperlipidemic diet, consisting mainly on whole soybean. The mean intervals to the first and second postpartum ovulations were 26.3 and 35.9 days for animals of T1 and 21.7 and 37.4 days for those of T2. The average intervals from calving to onset of the luteal activity, […]

With the objective to estimate the genetic parameters for milk and fat production of Holstein cows breed, the records from the Goiana Holstein Breed Producer Association using 3043 lactation of 2031 cows daughters, of 178 sires assigned to 56 herds in three different region of the Goias State, from 1990 to 1995 were analyzed. The means and standard deviations for milk production (MP) and fat production (FP) were 4458 ± 2150 kg and 149 ± 74 kg, respectively. The data […]

The objectives of this work were to estimate of genetic parameters for scrotal circumference (SC) at 12 (SC12, n = 652) and 18 (SC18, n = 607) months of age, age at first calving (AFC, n = 1,582), first (FCD, n = 1,582) and second (SCD, n = 644) calving dates and first calving interval (FCI, n = 644) in Nellore cattle. Parameters were estimated using REML methodology, with animal models and considering the relations among 15,648 animals. Heritability estimates […]

Breeding values were predicted by iterating on data using reduced animal model. Body weight at 35 days of age from two lines of meat-type chickens was measured in two generations and data file was consisted on 1044 parents (base population), 829 progeny parents and 9039 progeny non-parents. The number of iterative rounds and processing time for mixed model equations solutions via iterating on data were evaluated using seven convergence criteria (101 to 10-5). A total of six rounds of iteration […]

The development of linkage maps has stimulated the search for methods to map genes involved with quantitative trait loci (QTL). A sib par method based on the relation between individuals identic by descent (IBD) has been used to map QTLs. The objective of this paper was to extend the HASEMAN and ELSTON (1972) method to estimate the proportion (p) of genes IBD in half-sib families. The obtained results suggested that the used procedures were efficient to estimate p even when […]

The objective of this work was to verify if it is necessary to adjust the 305-day milk yield for yield in the early lactation in determining the effect of days open on milk production. The yields in early lactation were represented by the cumulative yield up to 80, 100 or 120 days and summit production. The analyses were conducted for the first and following lactation using models that accounted for present and previous days open, respectively. An animal model for […]

An experiment was carried out to verify the effect of different levels of sodium and phosphorus (P) on the performance, eggshell quality and on some blood constituents of 144 laying hens Hy-Line W36, aged 60 weeks, allotted to 36 experimental units with four hens each. A randomized experimental block design was used in a factorial arrangement (3 x 3), sodium levels (.16, .20 and .24%) and phosphorus levels (.35, .45 and .55%), totalizing nine treatments, two blocks with two replicates […]