By killing cattle and otherwise complicating management, the many species of larkspur (Delphinium spp.) present a serious, intractable, and complex challenge to livestock grazing management in the western United States. Among the many obstacles to improving our understanding of cattle-larkspur dynamics has been the difficulty of testing different grazing management strategies in the field, as t...

Supplementation of cows grazing rangelands is often beneficial to overcome nutrient deficiencies or imbalances. However, supplemental feeds and their delivery to the cow herd are expenses and thus supplementation decisions should be carefully made to ensure that costs are minimized and benefits in terms of cow performance exceed supplementation costs. When supplementing cows, there are question...

Commercial cow-calf producers commonly use the term “percent calf crop,” but what does it mean? Does percent calf crop represent the number of calves born relative to the number of cows bred, or perhaps it is the number of calves born relative to the number of cows exposed to a bull? Some might calculate percent calf crop as the number of calves weaned compared to the number of calves born, or ...

Mycoplasma bovis causes mastitis in dairy cows and is associated with pneumonia and polyarthritis in cattle. The present investigation included a retrospective case-control study to identify potential herd-level risk factors for M. bovis associated disease, and a prospective cohort study to evaluate the course of clinical disease in M. bovis infected dairy cattle herds in Switzerland. Eighteen ...

Dairy cow mortality is an increasingly severe problem for the US dairy industry. The objective of this study was to examine a variety of herd management practices and herd characteristics to identify factors associated with increased cow mortality in US dairy herds. The National Animal Health Monitoring System's Dairy 2002 study surveyed dairy operations in 21 major dairy states. The complete d...

The objective of this study was to describe the incidence of papillomatous digital dermatitis in the US (including regional and herd size patterns) and to evaluate specific herd-level management factors associated with high incidence of digital dermatitis in US dairy herds. The study design was a population-based cross-sectional survey. US dairy operations with at least 30 cows in 20 states, re...

Serum biochemical parameters can be utilized to evaluate the physiological status of an animal, and relate it to the animal's health. In order to accurately interpret individual animal biochemical results, species-specific reference intervals (RI) must be established. Reference intervals for biochemical parameters differ between species, and physiological differences including reproductive stat...

A severe outbreak of dermatophilosis occurred in 1985 in a herd of Brahman cows imported from Martinique in Guadeloupe in July 1983. Little was known on this disease in Guadeloupe until then, for the local zebu breed is naturally highly resistant to diseases transmitted by ticks or associated with them. Conditions of appearance and development of the disease were studied in relation with herd m...

Voluntary waiting period and adoption of synchronized breeding (ovulation synchronization followed by timed artificial insemination) were characterized from 33 million services of Holsteins and Jerseys in Dairy Herd Improvement herds. Calving month, calving year, and parity had large effects on days to first service for both breeds. Holstein cows that calved during March and April were bred lat...

BACKGROUND Infection with Mycobacterium avium subspecies paratuberculosis (MAP) has been associated with reductions in milk production in dairy cows and sub optimal fertility. The aim of this study was to highlight the production losses associated with testing MAP ELISA positive in Irish dairy cows. Secondary objectives included investigation of risk factors associated with testing MAP ELISA po...