The objective ofthis study was to evaluate the efficacy of intramammary tilmicosin, administered at drying-off, for eliminating Staphylococcus aureus infection, and to identify risk factors for S. aureus cure during the dry period. A total of 219 naturally infected cows, representing 308 quarters, w...

An acute onset of illness was reported in a lactating dairy herd in Canada in which monensin had been incorporated in error in its ration at almost 10 times the prescribed level. All of the lactating cows became lethargic, were inappetant, developed diarrhea, and had decreased milk production from 2...

Our objective was to describe cow and quarter-level factors associated with drying-off, and to evaluate their impacts on new intramammary infections (IMI) during the dry period. Data from 300 cows in five research herds were collected starting 2 weeks prior to scheduled drying-off. Variables of inte...

Although there is increasing concern over routine administration of long-acting antibiotics to all cows at the end of lactation, the practice is required to eliminate subclinical infections that are present at drying off. Alternatives to dry cow therapy (DCT) for preventing new infections from occur...

Milk samples from 50 sheep on a single Scottish research farm were collected weekly for 10 wk postpartum. Samples were analyzed for somatic cell counts (SCC) each week and bacteriologic culture was done for 7 of the 10 wk. A total of 492 udder half samples were cultured, of which 467 had correspondi...

Effective aids to decision-making for clinical mastitis therapy are reviewed..

A total of 1317 Holstein cows from 45 farms in the Canadian provinces of Quebec, Prince Edward Island (PEI) and Ontario, Canada were enrolled in a randomized trial between 1998 and 1999 to further confirm the efficacy of a monensin controlled release capsule in preventing periparturient disease in l...

The purpose of this study was to 1) estimate the herd prevalence of contagious mastitis pathogens in bulk milk from Prince Edward Island (PEI) dairy farms, 2) determine the association between bulk milk culture results and mean bulk milk somatic cell count (BMSCC), and 3) investigate the agreement o...

The objective of this study was to compare the efficacy of an intramammary infusion, containing tilmicosin phosphate, to an infusion of a negative control intramammary placebo for preventing new intramammary infections (IMI) during the dry period. Cows were enrolled from 24 dairy herds from three ge...

Plasma progesterone (P4) levels were assessed by radioimmunoassay in lactating dairy cows treated with a progesterone-releasing intravaginal device (PRID). Group A cows (N=6) received no treatment. PRIDs were administered to Group B1 (N=3) on day 25 after the first observed estrus (Day 0) and to Gro...

Streptococcus agalactiae continues to be a major cause of subclinical mastitis in dairy cattle and a source of economic loss for the industry. Veterinarians are often asked to provide information on herd level control and eradication of S. agalactiae mastitis. This review collects and collates relev...

The objective of this field trial was to compare the effect of intrauterine (i.u.) antibiotic or intramuscular (i.m.) prostaglandin F2 alpha (PGF2 alpha) on time to pregnancy in dairy cows diagnosed with clinical endometritis between 20 and 33 days in milk (DIM). The case definition of endometritis ...

The objectives of this study were to validate diagnostic criteria for clinical endometritis in postpartum dairy cows and to measure the impact of endometritis on reproductive performance. Data were collected from 1865 cows in 27 herds, including history of dystocia, twins, retained placenta, or metr...

The objective of this study was to assess the use of GnRH in a controlled breeding program (7 d prior to the second of two injections of PGF2 alpha, 14 d apart) as a means to improve the expression and detection of estrus, first service conception rate, and overall pregnancy rate of lactating dairy ...

Staphylococcus aureus is the most prevalent pathogen causing intramammary infections (IMI) in dairy cattle worldwide. New treatment regimens have been evaluated to increase cure rates. A systematic review was conducted to answer this question: what is the best antibiotic treatment for S aureus IMI o...

The objectives of this study were: 1) to determine if bulk tank milk urea nitrogen (BTMUN) and whole herd weighted average of the individual cow MUN levels (WHMUN) were equivalent measurements of herd MUN status; and 2) to determine the seasonal variation in BTMUN concentrations in Prince Edward Isl...

The purpose of this study was to survey the seroprevalence of infection with the agents of production-limiting diseases in dairy cattle in New Brunswick, Nova Scotia, and Prince Edward Island. In 30 randomly selected herds per province, 30 cattle per herd were randomly selected and tested for antibo...

Survey responses from 75 randomly selected dairy producers on Prince Edward Island were summarized to obtain a demographic picture of the dairy industry in this province and to determine information management practices and demands for the future. The results indicate a preparedness for dairy produc...

OBJECTIVE: To determine whether half-udder intramammary infusion of cloxacillin results in transfer of cloxacillin from treated to untreated mammary gland quarters within nonlactating cows, and, if so, at what concentrations, and to determine whether selection of ipsilateral versus diagonal-contrala...

The primary purpose of this research was to determine associations among seropositivity for bovine leukemia virus (BLV), bovine viral diarrhea virus (BVDV), Mycobacterium avium ssp. paratuberculosis (MAP), and Neospora caninum (NC) and each of 3 outcome variables (305-d milk, fat, and protein produc...

Herd prevalence and incidence of mastitis caused by Streptococcus agalactiae was determined for dairy cattle on Prince Edward Island during December 1992 and June 1994. For each census, bulk tank milk samples from all dairy herds (n = 452) in the province were tested on two occasions, and the result...

The purpose of this study was to evaluate the reliability (precision and accuracy), and repeatability of an infrared method of determining milk urea nitrogen. The reference method used for the reliability assessment was a wet-chemistry, enzymatic determination of milk urea nitrogen. Reliability and ...