Impaired fertility is the main reason for involuntary culling of dairy cows in Sweden. The objective of this study was to map quantitative trait loci (QTL) influencing fertility and calving traits in the Swedish dairy cattle population. The traits analyzed were number of inseminations, 56-d nonreturn rate, interval from calving to first insemination, fertility treatments, heat intensity score, ...

The most recent issue of the Journal of Dairy Science has several papers regarding decreased fertility in dairy cattle, and the efforts to develop hormonal treatment regimens to improve fertility. Much of the recent work focuses on trying to reduce loss of fetuses during early pregnancy. This prompted me to search the literature about this extensive and important subject area. I suspect that Ut...

For the current research the records of 62 farms in Isfahan province were available. To estimate genetic and phonotypic trends of reproductive traits such as age at first calving, calving interval, days open and number of insemination to conception rate the records of 63,866 cows including 167793 reproductive records were employed. Farms were covered by Vahdat industrial Agriculturists and Dair...

For the current research the records of 62 farms in Isfahan province were available. To estimate genetic and phonotypic trends of reproductive traits such as age at first calving, calving interval, days open and number of insemination to conception rate the records of 63,866 cows including 167793 reproductive records were employed. Farms were covered by Vahdat industrial Agriculturists and Dair...

Pure Holstein (HO, n=430), crosses between Swedish Red and HO (SRxHO, n=41), Montbeliarde and HO (MOxHO, n=18), and MO and SRxHO (MOxSH, n=53) were compared for milk, fat and protein yield, fat and protein percentage, somatic cell count (SCC), milking time (MT), and age at fi rst and second calving. A total of 180,933 test-day information for milk yield and MT, and 5,249 for fat and protein per...

Increasing feed costs and the desire to improve environmental stewardship have stimulated renewed interest in improving feed efficiency of livestock, including that of US dairy herds. For instance, USDA cost projections for corn and soybean meal suggest a 20% increase over 2010 pricing for a 16% protein mixed dairy cow ration in 2011, which may lead to a reduction in cow numbers to maintain pro...

the purpose of this study was to investigate the effect of maternal inbreeding on incidence of twinning,dystocia and stillbirth in holstein cows of iran. calving records from march 2000 to april 2009 comprisingof 365,021 calvings on 153,802 cows from 86 dairy herds were used. the mean level of inbreeding was0.7%, less than 37% of all animals were inbred, and a small proportion (3.45%) of inbree...

The purpose of this study was to determine the prevalence of bovine leukemia virus (BLV) in Khorasan Razavi and Khorasan Shomali provinces which are the main provinces located in the northeast of Iran. Total number of 429 blood samples were collected from industrial dairy herds. The samples were categorized based on province, age (2-3, 4-6, and 7-10 years old), calving (≤ 2, 3-5, and > 5) and h...

   This paper intended to review the lameness in dairy cattle. But it was necessary to have an overview about the hoof anatomical structure, it's growth and overgrowth properties. Most common causes of lameness such as laminitis and its different clinical form or presentation such as sole ulcers, toe ulcers, white line disorders, sole and white linehemorrhages have been reviewed and discussed. ...

Environmental effects on fertility measures early in lactation, such as the interval from calving to first luteal activity (CLA), proportion of samples with luteal activity during the first 60 days after calving (PLA) and interval to first ovulatory oestrus (OOE) were studied. In addition, traditional measurements of fertility, such as pregnancy to first insemination, number of inseminations pe...