in this study we estimated the allele and genotype frequencies of scd1 and dgat1 gene polymorphism. the analysis was conducted on 408 holstein cows from five dairy herds in isfahan province. genotypes were identified using pcr-rflp technique. two genetic variants (a and v) of the scd1 gene were observed in this experiment. the frequency of a-allele ranged from 0.49 to 0.66, while frequency of v...

The transition from pregnant, non-lactating to non-pregnant, lactating is too often a disastrous experience for the cow. Most of the metabolic diseases of dairy cows milk fever, ketosis, retained placenta, and displacement of the abomasum occur within the first 2 wk of lactation. In addition to metabolic disease, the majority of infectious disease experienced by the dairy cow, especially mastit...

The transition from pregnant, non-lactating to non-pregnant, lactating is too often a disastrous experience for the cow. Most of the metabolic diseases of dairy cows milk fever, ketosis, retained placenta (RP), and displacement of the abomasum occur within the first two wk of lactation. In addition to metabolic disease, the majority of infectious disease experienced by the dairy cow, especially...

In contrast to nonruminants, forage-fed ruminants normally absorb very little glucose from their feed. However, glucose supply is still crucial for maintenance and productive functions in ruminants, such as growing and lactating cattle. Glucose supply is especially important for the lactating dairy cow because of the demands of milk synthesis for glucose. Glucose requirements of ruminants are l...

Essential oils (EOs) from plant extracts have been reported to have an antibacterial activity against gram-negative and gram-positive bacteria. Several of the gram-positive bacteria are involved in ruminal biohydrogenation of fatty acids (FAs), thus suggesting that feeding EOs could lower biohydrogenation of FA because of a decrease in the number of bacteria involved in that process. As a resul...

The objective of this research, was to quantify sustainability indicators of organic dairy farms using Automatic Milking Systems (AMS), and a comparative group of organic dairy farms using conventional milking systems (CMS). Milk yield per cow was higher for AMS farms but did not result in higher net return to management. Nitrogen surplus per ha of available land was higher for AMS farms, Anima...

the financial losses, absolute and net economic values (evs) for direct (dcd) and maternal calving difficulty (mcd) were estimated using a bioeconomic model and taking into account the categorical nature of the trait. the effects of dystocia on other traits were estimated. but because of low reliability they were not considered for calculations in the base situation. in the base situation, the ...

The aim of this study was to characterize calving behavior dairy cows and compare the duration frequency behaviors for assisted unassisted at calving. Behavioral data from nine hours prior were collected 35 Holstein-Friesian cows. Cows continuously monitored under 24 h video surveillance. standing, lying, walking, shuffle, eating, drinking contractions recorded each cow until birth. A generaliz...

A longitudinal study was conducted to examine the relationship between lameness and delayed ovarian cyclicity during the first 60 d postpartum and days to first luteal activity during the first 300 d postpartum in Holstein cows. Two hundred thirty-eight cows from a 600-cow dairy that calved during a 12-mo period were used. Cows were classified into 1 of 6 categories of lameness during the first...

Sheep adapted to consume tannins rich feeds such as oak leaf (OL) appear to develop defensive mechanisms by their ruminal bacteria against these polyphenols. The capabilities of ruminal isolated tannins resistant bacteria from these animals to ferment a tanniniferous feed (i.e., pistachio hulls, (PH) which were incubated with rumen fluid from Holstein dairy cows was assessed. Six g positive coc...