mastitis in cattle is a serious problem which causes considerable economic losses in the dairy cattle herds. the aim of this survey was to identify mycoflorain milk of healthy, clinical and subclinical mastitis of lactating holstein dairy cows. milk samples of 154 holstein dairy cows were collected from 10 dairy cattle herds in suburb of mashhad-iran. the treatment groups included 104 lactating...

Stochastic simulation models are widely accepted as a means of assessing the impact of changes in daily management and the control of different diseases, such as paratuberculosis, in dairy herds. This paper summarises and discusses the assumptions of four stochastic simulation models and their use in the design of certification, surveillance, and control strategies for paratuberculosis in cattl...

Faecal samples from 291 dairy calves from 10 dairy herds in Kerman were examined to investigate theprevalence of Cryptosporidium infection. Cryptosporidium spp. oocysts were identified by using themodified Ziehl-Neelsen staining technique in 63 (21.65%) calves. Calves were grouped according to theirage as follows:

Gender selected or sexed semen has been commercially available to the dairy industry for almost a decade. However, sexed semen from beef bulls has only recently become commercially available. The availability of sexed semen from beef bulls along with concerns about success of the technology at the ranch level has limited the use of sexed semen in purebred and commercial beef operations. Recent ...

Gender selected or sexed semen has been commercially available to the dairy industry for almost a decade. However, sexed semen from beef bulls became commercially available only recently. The availability of sexed semen from beef bulls along with concerns about success of the technology at the ranch level has limited the use of sexed semen in purebred and commercial beef operations. Recent chan...

A stochastic bio-economic model has been used to determine the effects of new reproductive technologies over a 15-year period. A strategy of using conventional artificial insemination (AI) or embryo transfer (ET) using two sex-controlled embryos at different conception rates (CRs) and herd sizes resulted in a 24 state model. The genetic means of AI population increased over the years, and the g...

To assess the profitability of control schemes for Mycobacterium avium subspecies paratuberculosis (Map)-infection implemented in dairy herds, accurate estimates of its production effects are needed. This study aimed at quantifying the variation in milk yield of dairy cows according to their Map-infection status. The cow-status was determined by combining (i) its testing(s)-result(s) (serum ELI...

The objective of this study was to describe and compare the genetic structure (TNF-alpha -position 824) of dairy cattle herds infected and not infected with the bovine leukemia virus (BLV). The results of the present study indicate that BLV-positive herds were characterized by similar genetic structure (TNF-alpha -824A/G). The genetic equilibrium in these herds was preserved, but a tendency to ...

The relationship of first score and length of life in the herd was measured in Holstein females two or three years of age at first classification. The regression of herd life (number of times classified) on the first over-all type score (nearly all values were between 65 and 90 points) was 1.7 months. Correlation between first classification score and herd life was approximately 0.2, indicating...

The objective of this study was to evaluate the relationships between milk urea nitrogen (MUN) and other factors and the probability of conception in dairy cows. Data were retrieved from the Lancaster Dairy Herd Improvement Association (DHIA). A total of 713 dairy herds and 10,271 dairy cows were included in the study. Logistic regression was used to determine the within-herd effects of MUN, mi...