The objective of this study was to determine the long-term effects of feeding monensin on methane (CH4) production in lactating dairy cows. Twenty-four lactating Holstein dairy cows (1.46 +/- 0.17 parity; 620 +/- 5.9 kg of live weight; 92.5 +/- 2.62 d in milk) housed in a tie-stall facility were used in the study. The study was conducted as paired comparisons in a completely randomized design w...

To establish sustainability in the dairy industry, it is important that cows become pregnant at a biologically optimal time and at an economically profitable interval after calving. In this review, the results obtained from Holstein cattle in an experimental herd for dairy research are summarized. First, the effect of age at first calving of heifers on productive and reproductive performance wa...

this study was conducted to evaluate the effects of inclusion of monensin alone or in combination with methafix (a commercial product containing malate and fumarate) in the diets of lactating dairy cows on ruminal parameters and serum metabolites. four multiparous holstein lactating dairy cows (657± 12 kg of live weight; 133 ± 41days in milk) were assigned to one of the four dietary treatments....

In ruminants excess dietary Nitrogen (N) is excreted as urea mainly through urine. Urea, the major form of urinary N is rapidly converted to ammonia after excretion. Ammonia is an important environmental pollutant that impacts the quality of human and animal life .The NRC (2001) considered ammonia emissions from concentrated animal feeding operations (CAFO) as a major air quality concern. Ammon...

Objectives were to compare circulating progesterone (P4) profile and pregnancies per AI (P/AI) of two commercial intravaginal P4 devices (PRID-Delta(®) vs CIDR(®)). In Experiment 1, ovariectomized dairy cows (PRID-Delta, n=6 vs CIDR, n=6) were sampled throughout 7 days to measure circulating P4. In Experiment 2 (PRID-Delta, n=399 vs CIDR, n=375), cows were assigned to treatments, as follows: D0...

AIM Bovine ovarian cysts are a common cause of economic loss in modern dairy herds. The objective of the present study was to evaluate the reproductive responses to three protocols using hCG, GnRH and cloprostenol when the definite diagnosis of the type of ovarian cyst is/is not possible in dairy cows. MATERIALS AND METHODS A total of 144 lactating dairy cows with ovarian cysts were divided i...

Reproductive failure in inseminated cattle results from poor fertilization and embryo survival. Recent studies utilizing dairy and beef cattle indicate that fertilization rates are higher for nulliparous dairy and beef heifers and nonlactating beef cows than lactating beef and dairy cows and nonlactating dairy cows. Several factors affect fertilization rates, but the greatest impact was observe...

Previous research indicates that high blood urea nitrogen (BUN) concentrations are associated with decreased fertility in lactating dairy cows.This experiment was done to evaluate the effects of equine chorionic gonadotropin (eCG) administration (with or without eCG) on fertility of lactating dairy cows with different levels of BUN subjected to fixed-time artificial insemination (FTAI).Ovulatio...

the objective of the present study was to compare the efficacy of conventional and extendedintramammary (imm) therapy of persistent subclinical mastitis in lactating dairy cattle using nafcillinpenicillin-dihydrostreptomycin combination (npd). sixty-five dairy cows with 126 infected quarters were enrolled in the study. infected cows were allocated randomly to 1 of 3 different treatment regimens...

bovine viral diarrhoea virus (bvdv) is an important pathogen of dairy cattle. in this study, bulk milk samples representing a total of 4105 milking cows, from 18 dairy cattle herds in the suburb of mashhad- iran, were tested for presence of bvdv by the use of a nested reverse transcription polymerase chain reaction (nested rt- pcr) assay. non of the cows in the herds had been vaccinated against...