Reproductive efficiency in the dairy herd is the most important factor for its economic success and a major concern for dairy farmers when using artificial insemination (AI) or natural service (NS). Our objectives were to estimate, compare and analyse the costs associated with breeding cattle by do-it-yourself (DIY) AI and NS and identify the factors that influence them, under typical dairy far...

This research sought to determine the effect of selected milk protein polymorphisms on reproduction parameters 598 black and white Polish Holstein–Friesian cattle. The analyzed genes were kappa-casein (CSN3) beta-lactoglobulin (BLG). following reproductive indexes selected: age at first calving, interpregnancy period, calving interval, insemination index. influence identified genotypes course p...

Reproduction is associated to the profitability of beef herds, which affects level productivity and influenced by nutritional level. The objective this study was evaluate effect protein energy supplementation, before after parturition, on reproductive variables Nellore primiparous cows extensively raised in Brazilian tropical savannah. Eighty pregnant heifers with parturition estimated for a 45...

The objective of this study was to evaluate main indicators of milk production on total 60 commercial dairy herds from the Czech Republic during a 9-yr period (2006-2014). Breakeven points and sensitivity analysis were used and associations of age at first calving (AFC), milk yield (MY) and calving interval (CI) were analyzed. Lowest AFC≤749 d showed the highest fertility, the lowest death rate...

Body condition score (BCS), energy content (EC), cumulative effective energy balance (CEEB), and blood serum concentrations of glucose, beta-hydroxybutyrate (BHBA), and nonesterified fatty acids (NEFA) were measured throughout first lactation in 497 Holstein cows raised on a large commercial farm in northern Greece. All these traits are considered to be indicators of a cow's energy balance. An ...

The problem of postpartum anoestrus is a real one because it results in prolongation of the time between calvings. The interval between the calving and resumption of cyclic ovarian activity depends on several factors, i.e., amount of feeding before and after parturition, level of milk yield, age of the animal, calving difficulty, presence of a bull in the herd, season and its photoperiodism and...

Data from 528 male and 645 female progeny of 63 sires were used to estimate genetic correlations between female and male reproductive traits. Data were from two Hereford herds involved in a long-term selection program of the North Carolina Agricultural Experiment Service. Testicular measurements of circumference, diameter, length and volume were obtained on bulls at 205 and 365 d. Testicular gr...

The objectives were to characterize repeat breeding in dairy cows, including reproductive performance and risk factors. Data from 613 Holstein Friesian cows in nine dairy herds across Japan were enrolled. A repeat breeder was defined as a cow that did not become pregnant after three inseminations, despite no clinically detectable reproductive disorders. In contrast, cows that became pregnant wi...

The objective of this study was to evaluate effects of a daily oral drench of Propylene Glycol (PG) on fertility in dairy cows experiencing seasonal heat stress. In treatment group, cows (n=9) were treated with drenching 250 ml propylene glycol once daily from 3 to 15 days post-partum following the morning milking. Another group of cows (n=9) was selected as untreated control. The serum beta-hy...