Story in Brief An extended interval from calving to first estrus in beef cattle may be associated with environmental stress and, suckling which increase the secretion of adrenocorticotropic hormone (ACT H) by the pituitary gland. Increased secretion of ACTH causes greater amounts of corticoids to be secreted by the adrenal gland. This experiment was designed to determine if treatment of anestro...

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...

Data on productive and reproductive performance of cows in dual-purpose herds were analyzed to determine the effect of some environmental and genetic factors on saleable milk yield (SMY), lactation length (LL), daily saleable milk per lactation (DMYL), calving interval (CI), and daily saleable milk per calving interval (MYCI) in dual-purpose herds in Yucatan, Mexico. Repeatabilities (re) for th...

In three consecutive years, spring-calving Hereford and Hereford x Angus cows (n = 348) were used to determine effects of level of supplemental energy or protein before and after calving on cowherd performance. Beginning on November 1, cows were individually fed 1.22 kg/d of a 40% CP (PROTEIN) or 2.44 kg/d of a 20% CP supplement (ENERGY) until calving. After calving, cows remained on the same s...

A 2-yr study using primiparous and multiparous, spring-calving, crossbred beef cows was conducted to evaluate the effects of supplemental whole corn germ on reproductive performance, calf performance, and serum leptin concentrations. Each year, cows were blocked by age and BCS and assigned randomly to one of three treatments: PRE (n = 115) cows received 1.14 kg/d (DM basis) of whole corn germ f...

The aims of this study were to determine some major biochemical alterations observed in first calving cows with udder edema during the periparturient period and to detect some associations between dietary factors and the disease. For that, the concentrations of some electrolytes (Na(+), K(+), Cl, Ca(2+), P and Mg(2+)), lipid (triglycerides and cholesterol) markers and lipoproteins (HDL, LDL and...

in the present study, to estimate genetic parameters and genetic and phenotypic trends in holstein dairy cows in the north of iran, the records from first lactation of 11398 collected from 1989 to 2006 were used. records were collected from 290 herds. productive traits were 305 day-2x adjusted milk and fat yield and reproductive traits were age at first calving, calving interval and dry days. g...

The milk yield and survival of 91 Holstein-Friesian dairy cows that had had a left-displaced abomasum (LDA) corrected laparoscopically were compared with those of 193 control cows matched for herd, parity and calving date. Ninety per cent of the LDA treatments were performed within four weeks after calving. The risk of being culled during the whole observational period of at least three years w...

Fertility and reproductive performance of Landim and Africander females were compared using data collected from 1968 to 1981 at the Chobela Research Station in Mozambique. Breeds were managed together and grouped by age and sex, except when separated for breeding. Traits were relative fertility (probability of fertile females calving from the first breeding season), age at first calving, first ...

stillbirth is defined as a calf death just prior to, during, or within 24 to 48 h of parturition. the exact cause of calf death in dairy cows in this period of time is unknown. the objective of this study was to investigate about the effective factors on stillbirth and also to estimate some of the genetic parameters in iranian dairy holsteins. data in the first and second lactation that have be...