Page Page Acknowledgments ......................................................................................... 2 Time of Initiating Dietary Fat Supplementation on Lactation and Reproduction .................................................................................. 3 A Soyhull:Soy Lecithin:Soapstock Mixture for Early Lactation Dairy Cows ................................................

Bovine Viral Diarrhea Virus (BVDV) is a Pestivirus of the Flaviviviridaefamily that infects cattle, and its widespread distribution can cause substantial economic losses worldwide. The aims of this study were: (1) to estimate the prevalence of animals persistently infected (PI) with BVDV in industrial dairy cattle herds in suburb of Mashhad- Iran; and (2) to compare the occurrence of persistent...

Objective-To assess the effect of lameness on culling of dairy cows in Tehran province. Design- Historical cohort study. Study population and procedures- 7067 first- and second-parity Holstein dairy cows that calved from March, 21 2007 to March, 20 2008 were until next calving or culling. Logistic regression was conducted data. Results-The overall lactational culling rate for eligible cows i...

The present study has been conducted to evaluate the effect of intramuscular administration of vitamin A during dry period in pregnant dairy cows which have already received it in their daily ration on vitamin A status of neonatal calves. Single intramuscular injection of 2000000 IU vitamin A was carried in 10 dairy cows at 7 months of pregnancy (group 1) and in another 10 dairy cows at 8 month...

Replacing cows on a dairy is a major cost of operation. There is a need for the industry to adopt a more standardized approach to reporting the rate at which cows exit from the dairy, and to reporting the reasons why cows are replaced and their destination as they exit the dairy. Herd turnover rate is recommended as the preferred term for characterizing the cows exiting a dairy, in preference t...

Objective-To assess the effect of lameness on culling of dairy cows in Tehran province. DesignHistorical cohort study. Study population and procedures7067 firstand second-parity Holstein dairy cows that calved from March, 21 2007 to March, 2

Introduction Investigating and comparing the two systems Comparing some technical efficiency ratios and profit Points to note about the comparison Conclusions References Abstract. In this study, budgets of herd dynamics, feed and energy supply, production and profit of alternative dairy farm systems were used to examine the effects of changing a 230 cow Holstein-Friesian (HF) dairy system to a ...

Dairy cow health is multifactorial and complex. High producing dairy cows have been described as “metabolic athletes,” but 30 to 50% of cows are affected by a metabolic or infectious disease around calving (LeBlanc, 2010). Cows are highly susceptible to metabolic and infectious disease during the transition period, or the period from 3 weeks before to 3 weeks after calving (Huzzey et al., 2007,...

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...

An understanding of the normal estrous-cycle length of the cow is important when managing and monitoring dairy-herd fertility. Although the normal interovulatory interval is widely considered to be 21 d, some studies have found alternative intervals to be more prevalent; previously, most of the variation in interval length was expected to be between cows. The aim of this study was to assess the...