Beef cattle breeders are increasingly being offered gene marker tests for important traits in the breeding objective. They must make an economically rational decision whether to use these tests. Besides a potential immediate effect in seedstock sales, gene marker tests will affect the genetic improvement rate in the population. To examine the returns in a multi-trait breeding objective a pseudo...

Impact assessment studies consistently show that the benefits generated by plant breeding are large, positive and widely distributed. Numerous case studies have concluded that investment in plant breeding research generates attractive rates of return compared to alternative investment opportunities, that welfare gains resulting from the adoption of modern varieties (MVs) reach both favoured and...

The objective of this study was to investigate the effect of hCG administration 5 days after breeding on plasma progesterone (P4) concentration and reproductive performance of oestrous-induced nulliparous dairy goats. A total of 59 nulliparous goats (36 Alpine and 23 Saanen) received intravaginal sponges with 60 mg medroxyprogesterone acetate for 9 days plus 200 IU equine chorionic gonadotrophi...

OBJECTIVE One of the common, but less studied deficiencies in mouse models of cerebellar disorders is impaired breeding capacity. Nevertheless, there is no extensive study in Lurcher (Grid2Lc) mice, a model of olivocerebellar degeneration. The aim of this work was to analyze a breeding capacity of these mutants. METHODS Lurcher females mated with healthy wild type males were compared with two...

The study objective was to determine the effect of chlortetracycline in an ad libitum trace-mineralized salt mix given to heifers before and(or) during bull exposure on the proportion pregnant and the time to conception in a fixed breeding period. Heifers (n = 768), 13 to 15 mo of age, were individually identified, immunized (Leptospira, Campylobacter fetus), examined (body condition score, vag...

the objective of the present study was to determine the grades of nonspecific bacterial infection of genitalia of repeat breeding cattle by a simple and rapid test under field condition. for this purpose, a total of 100 crossbred jersey cows comprising of 80 repeat breeding animals presented for treatment and 20 normal cyclic (control group) animals presented for artificial insemination at thei...

OBJECTIVE To identify and compare the immature Culicidae population and their predators in different breeding places in a public city park. METHODS The study was carried out in an ecological park situated in the outskirts of the city of São Paulo, Brazil. Four Culicidae breeding places were selected: one semi-permanent, two permanent and one polluted brook. Throughout a year, at monthly inter...

The objective of this study was to compare the accuracy of estimating and predicting breeding values using two diverse approaches, GBLUP and BayesC, using simulated data under different quantitative trait locus(QTL) effect distributions. Data were simulated with three different distributions for the QTL effect which were uniform, normal and gamma (1.66, 0.4). The number of QTL was assumed to be...

Development of gilts that conceive early and continue to produce offspring is a primary objective of swine production. The objective of this study was to determine the degree of feed restriction during development required to optimize reproductive performance and efficiency in gilts. The effects that various patterns of growth had on reproductive development and performance of gilts through d 3...