An electronic probe with parallel stainless steel electrodes was designed to measure changes in electrical resistance in the anterior vagina associated with increased cervical mucus secretion at estrus. Three groups of Holsteins were probed, and a sample of residual milk after milking was taken for progesterone assay every 2nd day for 28 to 40 days. Group I consisted of 29 cycling virgin heifer...

Two experiments were conducted to evaluate an accelerometer system (Heatime; SCR Engineers Ltd., Netanya, Israel) to manage reproduction in lactating dairy cows. In experiment 1, lactating Holstein cows (n=112) were fitted with an accelerometer system and were treated with GnRH followed 7d later by PGF(2α) to synchronize estrus. A total of 89 cows that had a follicle >10mm in diameter and a fun...

in this investigation 13699 data related to milk production from 2716 holstein first calving and daughter from 167 sire cows were analyzed based on random regression model (rr/cf) and reml method incomplete lactating (5-90 days) and (5-120 days) in correlations to complete lactating were 0.67 and 0.72, respectively with progress in complete 5-240 day was 0.91 the correlation value for lactating...

The effect of shifting calf-weaning age on profiles of energy status (BW, BCS, and rib and rump fat) and reproductive performance of beef cows was evaluated in a 3-yr study. Pregnant and lactating crossbred beef cows (n = 408), mainly of Angus and Hereford breeding, were stratified by age and by sex and BW of their calves and assigned randomly into 2 treatments: weaning at approximately 180 d (...

BACKGROUND Mycobacterium avium subspecies paratuberculosis (MAP) is the causative agent of Johne's disease (JD), or paratuberculosis in ruminants has been suspected to be implicated in the pathogenesis of Crohn's disease (CD) in humans with chronic inflammatory intestinal changes. As the hypothesis is now fast being recognized that MAP could possibly be the etiological agent of CD which is foun...

BACKGROUND Results regarding the use of bovine somatotropin for enhancing fertility in dairy cattle are variable. Here, the hypothesis was tested that a single injection of a sustained-release preparation of bovine somatotropin (bST) during the preovulatory period would improve pregnancy success of lactating dairy cows at first service. RESULTS The first experiment was conducted in a temperat...

The objective of this study was to determine the effect of GnRH (100 microg i.m.) treatment 5 and 15 days after timed insemination (TAI) on pregnancy rate and pregnancy loss in lactating dairy cows subjected to synchronization of ovulation. The study included 831 lactating dairy cows subjected to a Presynch-Ovsynch protocol for first service. On the day of TAI (Day 0), cows were randomly assign...

The aim of this study was to evaluate the potential effects of methyl donor supplementation of pregnant animals in the presence or absence of a concomitant lactation on the methylome of the offspring. Twenty Holstein cows, 10 nulliparous (non-lactating while pregnant) and 10 multiparous (lactating while pregnant) were blocked by parity and randomly assigned to an i.m. weekly injections of a pla...

Three experiments were conducted to investigate the effects of polyurethane coated urea on in vitro ruminal fermentation, ammonia release dynamics and lactating performance of Holstein dairy cows fed a steam-flaked corn-based diet. In Exp. 1, a dual-flow continuous culture was run to investigate the effect of polyurethane coated urea on nutrient digestibility, rumen fermentation parameters and ...

Female ruminants are susceptible to spontaneous ketosis arising at times of high productive demand. The dairy cow is most susceptible during the first 7 weeks of lactation, whereas the ewe is susceptible, particularly when multifoetate, during the last month of pregnancy. The disorder is characterized by signs of carbohydrate insufficiency and adipose-tissue mobilization. Those of carbohydrate ...