Although treatment of cycling cows with low concentrations of melengesterol acetate (MGA) results in formation of persistent follicles, in the absence of corpora lutea, it is not known whether persistent follicles form in anestrous cows in response to a similar treatment. The objective of this experiment was to determine the effect of long-term MGA treatment (14 d) on follicular dynamics and th...

The aim of this study was to evaluate the effect of the season (ambient temperature and relative humidity) on some blood metabolites in dairy cows during postpartum period. Blood samples were collected from 195 clinically healthy dairy cows of 8 Italian dairy herds in spring (April-May 15.5±4 °C and 69.5±0.7 %), summer (June-July 23±1.5 °C and 69±1.3 %) and autumn (September-October 17±2 °C and...

The postpartum uterus in dairy cows is susceptible to multiple bacterial pathogens and susceptibility to infection appears to be associated with periparturient immunosuppression and energy status. Neutrophils (PMN) play an important role as they provide the first-line of cellular defense against bacterial colonization within the uterus. Peripheral blood PMN functions of periparturient dairy cow...

The objectives of this study were: 1) to determine the effect of providing additional prepartum concentrate on the occurrence and severity of ruminal acidosis (RA) and lactational performance during the periparturient period in primiparous cows; and 2) to characterize the occurrence and severity of RA during the periparturient period. We hypothesized that providing additional concentrate prepar...

Mature Angus-cross beef cows (n = 144) were used to determine effects of late gestation dietary energy source on pre- and postpartum cow performance in a complete randomized block design experiment. Cows were adapted to diets starting at 167 +/- 9 d of gestation and fed until 1 wk before expected calving date. Cows were fed 1 of 3 dietary energy sources: grass hay (HY), corn (CN), or dried dist...

Objectives were to determine effects of lasalocid on reproductive performance and serum concentrations of leptin and IGF-I, and to correlate concentrations of leptin and IGF-I with reproductive performance of beef cows. Forty-one purebred, multiparous Brahman cows were blocked to control (C; n = 20) or lasalocid (L; n = 21) treatments by BW, BCS, and predicted calving date. Treatment began 21 d...

The objective of this study was to evaluate the influence of bull excretory products on the resumption of postpartum luteal function in primiparous, restricted-suckled cows. Hypotheses tested were that resumption of luteal function or proportions of cows that initiate luteal cycling did not differ among cows exposed to a bull (BE), exposed to excretory products of bulls (EPB), not exposed to a ...

A common feeding practice during the dry period is to switch dairy cows to an energy-dense diet 3 wk prepartum, but this practice may lead to the overconsumption of energy and increase the risk of metabolic disease postpartum. The aim of this trial was to compare the metabolic status of transition Holstein dairy cows fed a 77% forage diet (77F; NEl = 1.46 Mcal/kg; NDF = 41%) vs. those fed an 87...

In high-yielding dairy cows the liver undergoes extensive physiological and biochemical changes during the early postpartum period in an effort to re-establish metabolic homeostasis and to counteract the adverse effects of negative energy balance (NEB). These adaptations are likely to be mediated by significant alterations in hepatic gene expression. To gain new insights into these events an en...

the purpose of this research was the study of reproductive performance in postpartum dairy cows with different parities. twenty holstein dairy cows were assigned into two equal primiparous and multiparous groups. body weight and body condition score (based on 1-5 scoring) were measured every other week, starting from two weeks before calving till pregnancy confirmation. daily milk yield was als...