BACKGROUND Optimal body condition in early lactation is generally accepted as a prerequisite for good reproductive performance. Examination of milk progesterone profiles offers an objective method for characterization of postpartum ovarian activity in dairy cows. The present study investigated the relationship between body condition after calving, some metabolic parameters in blood plasma, and ...

Background: One of the most important metabolic factors affecting the reproductive activity is insulin-like growth factor-I (IGFI) concentration changes after calving. Recently, Maj et al. (2008) discovered a significant association between the IGF-I genotypes based on the 5'-untranslatedregion (5'-UTR) of IGF-I gene and the IGF-I blood level. The objective of this study is to investi...

calving records from april 1996 to december 2005 comprising 31863 calving events of 1173 dairy cows in a large commercial dairy herd were used to evaluate the effects of heat stress, using temperature-humidity index (thi) on milk yield and composition and reproductive performance of holstein dairy cows under humid climatic conditions of rasht in iran. thi values were grouped into six groups: 30...

Although the number of dairy farms is decreasing, that of large farms is increasing in Japan. Milk production in Japanese dairy cows has increased from 62 kg/year to 88 kg/year over the last 2 decades. However, Japanese dairy cows are experiencing a sustained decline in reproductive performance, calving intervals, and days open; further, the number of inseminations required for conception have ...

Subclinical mastitis is considered as one of the most prevalent diseases in dairy cows, causing drasticloss in the dairy industry. Oxidative stress, induced by reactive oxygen species (ROS), is believed to be aprimary factor in various cattle diseases including mastitis, but there are few studies regarding the role ofROS in subclinical mastitis. This study was undertaken to i) study the changes...

BACKGROUND Results regarding the use of bovine somatotropin for enhancing fertility in dairy cattle are variable. Here, the hypothesis was tested that a single injection of a sustained-release preparation of bovine somatotropin (bST) during the preovulatory period would improve pregnancy success of lactating dairy cows at first service. RESULTS The first experiment was conducted in a temperat...

Careful antemortem examination and interpretation of findings, assisted by good clinical records, do much to throw light on the nature of vertical fissure in cattle. During an eight month period of investigation, 13 (3.2%) lame cows with vertical fissure out of 52 Holstein cows with different claw fissures were selected for clinical and gross pathological purposes in a commercial dairy farm wit...

BACKGROUND A nationwide survey on the microbial etiology of cases of subclinical mastitis in dairy cows was carried out on dairy farms in Sweden. The aim was to investigate the microbial panorama and the occurrence of antimicrobial resistance. Moreover, differences between newly infected cows and chronically infected cows were investigated. METHODS In total, 583 quarter milk samples were coll...

The efficiency of feed utilization on dairy farms can be influenced by a variety of practices that are beyond the scope of this paper, including many aspects of the harvesting, storage, mixing, and delivery of feed components, as well as the grouping of animals according to nutritional needs. Two practices that will be addressed are: 1) improvement of the biological efficiency of lactating cows...

Metabolic disorders in animals are one of the most important problems in modern cattle production. The paper presents results characterising the functional state of the liver in dairy cows with clinical ketosis. The study was conducted on 17 Holstein cows (9 of them were clinically healthy with negative test for ketone bodies in urine and 8 with positive test) in their second to fourth lactatio...