Search Results
Results 351 - 400 of 1416
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Roche J R - - 2007
The objective of the present study was to identify and quantify relationships between body condition score (BCS) and body weight (BW) in dairy cows with reproduction variables in pasture-based, seasonal-calving dairy herds. Over 2,500 lactation records from 897 spring-calving Holstein-Friesian dairy cows were used in the analyses. Eleven BCS- and ...
Melendez P - - 2007
The objective of this study was to evaluate the relationship between reproductive performance and milk yield in central-southern Chilean Holstein cattle that calved from 1990 to 2003. The analysis included 150,457 lactations obtained from a certified recording system. Reproductive indexes included in the study were calving interval (CI, d), calving ...
Walsh R B - - 2007
The objectives of this research were to determine the prevalence of the anovulatory condition within a temperate region of North America and identify cow-level and herd-level risk factors for this condition. A total of 1,341 cows from 18 herds were classified as cycling or anovular based on skim milk progesterone ...
Saldarriaga J P - - 2007
The objectives of this study were to 1) compare cumulative pregnancy rates in a traditional management (TM) scheme with those using a synchronization of ovulation protocol (CO-Synch + CIDR) for timed AI (TAI) in Bos indicus-influenced cattle; 2) evaluate ovarian and hormonal events associated with CO-Synch + CIDR and CO-Synch ...
Spickett A M - - 2007
The effect of a decoction of pulverized aloe leaves (Aloe marlothii) mixed with tap water and administered orally through a gastric tube was determined against ticks on cattle. The decoction was administered to six randomly selected calves seven times at 3-day intervals while the remaining calves received an equivalent amount ...
Gifford C A - - 2007
In ruminants, pregnancy results in up-regulation of a large number of IFN-stimulated genes (ISG) in the uterus. Recently, one of these genes was also shown to increase in peripheral blood leukocytes (PBL) during early pregnancy in sheep. Our working hypothesis is that conceptus signaling activates maternal gene expression in PBL ...
Jousan F D - - 2007
Administration of recombinant bovine somatotropin (bST) to lactating dairy cows during heat stress increases milk yield, but it also can increase body temperature and may therefore compromise fertility. However, it is possible that bST treatment could increase fertility during heat stress because it has been reported to increase fertility in ...
Colazo Marcos G - - 2007
The objective was to optimize rebreeding of nonpregnant, previously inseminated beef cattle. In Experiment 1, 43 cows received a used intravaginal progesterone-releasing insert (IVPRI; Days 0-7) 12.3 d after ovulation and received concurrently no treatment, 100 microg gonadotropin releasing hormone (GnRH), 1 mg estradiol cypionate (ECP), or 150 mg progesterone. ...
Bó G A GA Instituto de Reproducción Animal Córdoba (IRAC), J.L. de Cabrera 106, X5000GVD, Córdoba, Argentina. - - 2007
The adaptation of Bos indicus cattle to tropical and subtropical environments has led to their widespread distribution around the world. Although artificial insemination (AI) is one of the best alternatives to introduce new genetics into Bos indicus herds, the peculiarity of their temperament and the tendency to show short oestrus ...
Thatcher W W WW Department of Animal Sciences, University of Florida, Gainesville, FL, USA. - - 2007
The objective of this review is to integrate strategies to optimize an ovulatory control program which then serves as a platform to improve the reproductive performance of lactating dairy cows. Programmed management of follicle growth, regression of the CL and induction of ovulation led to development of the Ovsynch program. ...
Walsh R B - - 2007
The objective was to compare the probability of pregnancy after fixed-time insemination in cows diagnosed as non-pregnant and re-inseminated following the Ovsynch protocol, with or without exogenous progesterone. Cows (n=415) used in this study originated from 25 farms. Upon diagnosis of non-pregnancy between 30 and 60 days after AI, cows ...
Hickson R E - - 2006
Breeding beef heifers for the first time at 15 months of age has potential to increase the efficiency of the beef breeding-cow herd. An increased incidence of dystocia in heifers calving at 2 years of age, compared to mature cows, is a major reason many farmers in New Zealand have ...
Caraviello D Z - - 2006
The fertility of lactating dairy cows is economically important, but the mean reproductive performance of Holstein cows has declined during the past 3 decades. Traits such as first-service conception rate and pregnancy status at 150 d in milk (DIM) are influenced by numerous explanatory factors common to specific farms or ...
Amundson J L - - 2006
Ten years of calving records were examined from Bos taurus crossbred cows (mean of 182 cows/yr) to quantify the effects of environmental conditions during the breeding season on pregnancy rate. Estimated breeding dates were determined by subtracting 283 d from the calving date. Relationships were determined between the proportion of ...
Zupancic Gregor D - - 2007
Treatment of brewery slurry in a thermophilic anaerobic sequencing batch reactor (ASBR) was studied using conventional fully mixed semi-continuous digestion as a control. The process phases were adapted to fit the brewery slurry discharge schedule. ASBR experiments were conducted under different organic loading rates (OLR) from 3.23 to 8.57 kg ...
Pegorer Marcelo F - - 2007
Heat stress has negative effects on pregnancy rates of lactating dairy cattle. There are genetic differences in tolerance to heat stress; Bos taurus indicus (B. t. indicus) cattle and embryos are more thermotolerant than Bos taurus taurus (B. t. taurus). In the present study, the effects of sire and sire ...
García-Ispierto I - - 2007
Infertility has been often correlated to a rising milk yield in high producing dairy cattle. The aim of the present study was to evaluate, using logistic regression procedures, the effects of several management indicators on the fertility of four dairy herds in northeastern Spain. Data derived from 10,965 artificial insemination ...
Pfeiffer Thomas T Program for Evolutionary Dynamics, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA. - - 2006
Picture a pasture open to all (...) As a rational being, each herdsman seeks to maximize his gain. Explicitly or implicitly, more or less consciously, he asks, "What is the utility to me of adding one more animal to the herd?" This utility has one negative and one positive component. ...
Kurykin J - - 2007
Our objective was to assess the effect on heifer pregnancy rate of deposition at three sites within the uterus of frozen-thawed sex-sorted sperm at a fixed time after estrus synchronization. Estrus was synchronized in 209 heifers by administration of PGF2a 14 days apart. At 80-82 h after the second PGF2a ...
Martin J L - - 2007
A 3-yr study was conducted with heifers (n = 170) whose dams were used in a 2 x 2 factorial arrangement of treatments to determine the effects of late gestation (LG) or early lactation (EL) dam nutrition on subsequent heifer growth and reproduction. In LG, cows received 0.45 kg/d of ...
Speidel S E - - 2007
In good environments, cow intake is sufficient for their own growth and for milk production to support their calf. In poor environments, cows lose BW or may reduce milk supply to maintain themselves. Heritability for direct genetic and maternal components of weaning weight as well as the correlations between these ...
Chebel R C - - 2006
The objectives of this study were to evaluate the effects of an intravaginal insert containing progesterone (CIDR, controlled internal drug releasing) administered in presynchronization and resynchronization protocols on cyclicity, detection of estrus, pregnancy rate, and pregnancy loss to first AI; reinsemination patterns; and pregnancy rates to second postpartum AI before ...
Han Hyungchul - - 2006
ISG15 is induced by conceptus-derived interferon-tau in the endometrium on days 15-45 of pregnancy. It was hypothesized that pregnancy induces blood cell ISG15 gene expression and that low blood ISG15 mRNA levels provide an indication of non-pregnant cows on day 18. Blood was collected either on day 18 (n = ...
Sousa N M - - 2006
In the last years, a polymorphic family of placenta-expressed proteins has been discovered in ruminant species and used for pregnancy diagnosis. Pregnancy diagnosis is an important part in reproduction management of ruminants. The pregnancy-associated glycoproteins (PAG) are synthesized in the mono- and binucleate cells of the ruminant's trophectoderm. Part of ...
Lamb G C - - 2006
We evaluated whether a fixed-time AI (TAI) protocol could yield pregnancy rates similar to a protocol requiring detection of estrus, or detection of estrus and AI plus a clean-up TAI for heifers not detected in estrus, and whether adding an injection of GnRH at controlled internal drug release (CIDR) insertion ...
Klisch K - - 2006
Binucleate trophoblast giant cells (BNC) in the bovine placenta produce glycoproteins, which are delivered into the mother after fusion of BNC with uterine epithelial cells. During most time of pregnancy, BNC produce pregnancy-associated glycoproteins (PAGs) and prolactin-related protein-I (PRP-I) with asparagine-linked lactosamine-type glycans terminating with N-acetyl-galactosamine. We show by lectin ...
Curley K O KO - - 2006
The objectives of this study were 1) to compare temperament assessments, using multiple techniques and over repeated observations, to gauge temperament over the long-term and 2) to evaluate the relationship of the temperament appraisals with serum concentrations of cortisol (CS). Measures of temperament were gathered over 3 repeated observations (60-d ...
Blevins C A - - 2006
Our objectives were to determine lactational and reproductive outcomes in response to increased milking frequency (MF), injection of estradiol cypionate (ECP), and treatment with bovine somatotropin (bST). Lactating dairy cows (n = 144) were blocked by lactation number (1 vs. 2+) and assigned randomly to a 2 x 2 x ...
Pan Dinorah - - 2007
A survey of the natural occurrence of deoxynivalenol (DON) in barley harvested in Uruguay from 1996 to 2002 was conducted. A total of 292 samples were analyzed for DON by an immunochemical method using inmunoaffinity columns and fluorimetric detection. Between 26 and 100% of the samples were positive for DON ...
Perry G A - - 2007
Previous research indicated that the size of the ovulatory follicle at the time of insemination significantly influenced pregnancy rates and embryonic/fetal mortality after fixed-timed AI in postpartum cows, but no effect on pregnancy rates was detected when cows ovulated spontaneously. Our objective was to evaluate relationships of fertility and embryonic/fetal ...
Ivanek Renata - - 2007
Fecal shedding is an important mechanism of spreading of a number of human and animal pathogens. Understanding of the dynamics of pathogen fecal shedding is critical to be able to control or prevent the spread of diseases caused by these pathogens. The objective of this study was to develop a ...
De Vries A - - 2006
The objective of this study was to estimate the value of pregnancy for dairy cows. Effects of the stage of gestation, stage of lactation, lactation number, milk yield, milk price, replacement heifer cost, probability of pregnancy, probability of involuntary culling, and breeding decisions were studied. A bioeconomic model was used, ...
López-Gatius F - - 2007
The aim of this study was to determine whether plasma pregnancy-associated glycoprotein-1 (PAG-1) concentrations in pregnancy are affected by persistent Neospora caninum infection in dairy cows. The data analyzed were derived from 22 multiparous cows: 16 N. caninum-seropositive and 6 N. caninum-seronegative animals (used as controls). Three of the 16 ...
Heinonen M - - 2006
The prevalence of lameness among 646 sows and gilts in 21 selected herds was determined; 8.8 per cent of the animals were lame and the most common clinical diagnoses were osteochondrosis, infected skin lesions and claw lesions. The lame animals had higher serum concentrations of haptoglobin and C-reactive protein than ...
Umapathy Govindhaswamy - - 2007
In this paper the behavior of the Asiatic lion was studied during natural and gonadotropin-induced estrus in relation to fecal estradiol and progesterone concentration. The average length of estrus was 5.4 days and no significant difference was observed between natural and gonadotropin-induced estrus. Vocalization and rolling were the major estrus ...
Goshen Tamir - - 2006
Retained fetal membranes (RFM) and clinical metritis (CM) are frequently diagnosed disease conditions in dairy cows and considered of major economic impact due to negative effect on reproduction and milk production. The objective of this study was to evaluate the efficacy of i.u. tetracycline for the treatment of RFM and ...
Mazrier Hamutal - - 2006
The efficacy of the pedometer to predict lameness earlier than the appearance of the clinical signs in a herd of dairy cows was investigated by correlating pedometric activity (PA) with clinical cases of lameness. The computer program was set to identify cows with a reduction of 5% or more in ...
Baruah Tiluttoma - - 2006
Morphometric characters of the adult males of the Tai-Phake and the nature and extent of morphometric variation among five neighboring mongoloid groups of Assam have been examined in the present study. For the sake of investigation 12 anthropometric measurements have been taken and five indices have been calculated. In order ...
Bilby T R - - 2006
The objectives were to examine the effects of bovine somatotropin (bST), pregnancy, and dietary fatty acids on expression of key endometrial genes and proteins regulating prostaglandin synthesis in lactating dairy cows. Two diets were fed, at about 17 d in milk (DIM), in which oil of whole cottonseed (control diet) ...
Meadows Cheyney - - 2006
An observational study was conducted in order to assess the impact of a contract breeding program on the reproductive performance in a selected group of Ohio dairies using event-time analysis. The contract breeding program was offered by a breeding co-operative and featured tail chalking and daily evaluation of cows for ...
Perez-Alenza M D - - 2006
AIM: To describe changes in blood and urine analytes in a large group of cattle exposed to chronic bracken fern toxicity, in order to identify parameters of potential diagnostic value. METHODS: The study was conducted on two livestock farms on which bovine enzootic haematuria (BEH) was known to occur; Farm ...
Bormann J Minick - - 2006
The objective of this project was to determine the genetic control of conception rate, or pregnancy percentage in Angus beef heifers. Producers from 6 herds in 5 states provided 3,144 heifer records that included breeding dates, breeding contemporary groups, service sires, and pregnancy check information. Two hundred fourteen sires of ...
Haugejorden G - - 2006
Determination of plasma concentrations of pregnancy associated glycoproteins (PAG) has been used for early pregnancy diagnosis in cows. However, this is complicated by the presence of PAG in plasma for an extended period postpartum. The main objective of the present study was to investigate the postpartum elimination rates of pregnancy ...
Waldmann Andres - - 2006
Milk progesterone concentration (P4), milk yield, milk composition, ovarian structures and pregnancy status were studied in 108 cows treated with two doses of PGF 14 days apart and inseminated at fixed time (TAI) 80-82 h later. The synchronization protocol was started at 70+/-1.4 days after parturition. Milk P4 profiles revealed ...
Losinger Willard C - - 2006
An examination of the economic impacts of reduced milk production associated with Johne's disease on Johne's-positive and Johne's-negative dairy operations indicated that, if Johne's disease had not existed in US dairy cows in 1996, then the economic surplus of Johne's-negative operations would have been $600 million+/-$530 million lower, while the ...
Roche J R - - 2006
The objective of the present study was to quantify the climatic, animal, and management factors influencing incidence of milk fever (MF) in cows exposed to grazing systems. Data were extracted on 4,469 calvings of multiparous cows in a seasonal calving research herd between 1970 and 2000. Climatic data during the ...
Stevenson J S - - 2006
Our objective was to determine whether progesterone (P4) supplementation during an Ovsynch protocol would enhance fertility in lactating dairy cows. Lactating dairy cows (n = 634) at 6 locations were assigned randomly within lactation number and stage of lactation to receive the Ovsynch protocol [OVS; synchronization of ovulation by injecting ...
Cornwell J M - - 2006
Sire fertility may influence pregnancy rate (PR) by differences in sperm survival in the female reproductive system and time required for capacitation and transport of sperm to site of fertilization. A predicted fertility index, Estimated Relative Conception Rate, was used to select 3 high-fertility artificial insemination (AI) sires (+3) and ...
Renquist B J - - 2006
Pregnancy rate, calving interval, birth weight, weaning weight, and quarterly BCS were collected for 5 consecutive years on 454 fall-calving multiparous British crossbred cattle (3 to 10 yr of age) to evaluate associations of age with BCS and production parameters. Body weight and BCS were collected pre-calving, prebreeding, at weaning, ...
Kharche S D - - 2007
The aim of this study was to investigate the effect of treating repeat breeder dairy crossbred cows with different doses of GnRH analogue through i.m. at the time of artificial insemination, on pregnancy rates from their first service after treatment and overall pregnancy rates. One hundred and thirty seven crossbred ...
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