1,726,746 research outputs found
The effects of maedi-visna virus infection on productivity in ewes
No full textFive sets of data from four separate sheep flocks (1445 ewes) were used to assess the effects of subclinical maedi-visna virus infection (as determined by serological procedures) on productivity in ewes. In general, infection with maedi-visna virus lowered productivity. Infection reduced conception rates, with the chances of an infected ewe conceiving being only approximately 0.67 times those of a non-infected ewe. For ewes which did conceive, there was no effect of infection on the number of lambs born. The birth weights of lambs born to middle-aged (3-4 years) infected ewes were 3-6% lower than the weights of lambs born to non-infected ewes of the same age. There was very little effect of infection in younger (1-2 years) and older (5+ years) ewes: some factors which may have biased these results are discussed. Lamb weights at 25-50 days of age were reduced by maedi-visna infection in the ewe but the results were not statistically significant..RE: 33 ref.; SC: ZA; CA; VE; 0V; 0ISource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=4&issue=5%2f6&spage=471&pages=471-484&date=1987&title=Preventive%20Veterinary%20Medicine&atitle=The%20effects%20of%20maedi-visna%20virus%20infection%20on%20productivity%20in%20ewes.&aulast=Dohoo&pid=%3Cauthor%3EDohoo%2c%20I%20R%3bHeaney%2c%20D%20P%3bStevenson%2c%20R%20G%3bSamagh%2c%20B%20S%3bRhodes%2c%20C%20S%3C%2Fauthor%3E%3CAN%3E19872200103%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
Clinical mastitis and intramammary infections on Ohio dairy farms
No full textFifty Ohio dairy farms selected by stratified random sample were monitored to determine the incidence rate of clinical mastitis and prevalance of intramammary infection with the major intramammary pathogens. Population parameters for clinical mastitis incidence rate were estimated as 2.19, 3.33 and 4.36 cases per 100 cow-months at risk for herds with less than 50 cows, herds with 50-99 cows, and herds with more than 99 cows, respectively. The most common isolates from clinical cases were coagulase-negative staphylococci and Escherichia coli, each present in 14.6% of samples taken. Estimates of population prevalence of intramammary infection for Ohio dairy farms were: coagulase-positive staphylococci, 2%; coagulase-negative staphylococci, 2%; E. coli, 1%; other coliforms, 1%; Streptococcus agalactiae, 2%; esculin-positive streptococci, 5%; other esculin-negative streptococci, 3%..RE: 30 ref.; SC: CA; VE; BE; ZA; 0I; 0V; 2V; 0DSource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=12&issue=1-2&spage=59&pages=59-71&date=1992&title=Preventive%20Veterinary%20Medicine&atitle=Clinical%20mastitis%20and%20intramammary%20infections%20on%20Ohio%20dairy%20farms.&aulast=Bartlett&pid=%3Cauthor%3EBartlett%2c%20P%20C%3bMiller%2c%20G%20Y%3bLance%2c%20S%20E%3bHeider%2c%20L%20E%3C%2Fauthor%3E%3CAN%3E19922265228%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
Disease, production and culling in Holstein-Friesian cows. I. The data
No full textA two-and-a-half-year study was undertaken in 32 commercial diary herds within a 50-mile radius of Guelph, Ontario, to evaluate relationships amongst diseases, production parameters and risks of removal in Holstein-Friesian cows. Diseases consisted of common clinical diseases as well as two subclinical diseases (mastitis and ketosis). The data set consisted of a total of 2875 lactation records from 2008 cows. The means and standard deviations of some of the production parameters were: age 4.9 +or- 2.5 year, breed class average for milk 140 +or- 26 BCM units, milk production per day of life 18.0 +or- 3.8 kg and days to conception 118 +or- 60 days. Lactational incidence rates of the more common diseases were: reproductive tract infections 0.182, mastitis 0.168, cystic ovaries 0.104, subclinical ketosis 0.096, retained placenta 0.086 and ketosis 0.074. The average lactation mean log somatic cell count was 179 000 cells/ml. The times postpartum to the first diagnosis of all disease conditions are presented..RE: 20 ref.; SC: ZA; CA; VE; BE; 0V; 0ISource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=1&issue=4&spage=321&pages=321-334&date=1983&title=Preventive%20Veterinary%20Medicine&atitle=Disease%2c%20production%20and%20culling%20in%20Holstein-Friesian%20cows.%20I.%20The%20data.&aulast=Dohoo&pid=%3Cauthor%3EDohoo%2c%20I%20R%3bMartin%2c%20S%20W%3bMeek%2c%20A%20H%3bSandals%2c%20W%20C%20D%3C%2Fauthor%3E%3CAN%3E19842236589%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
The effects of lameness on reproductive performance, milk production and culling in Dutch dairy farms
No full textA retrospective cohort study design was used to investigate the effect of lameness on reproductive performance on 13 commercial Dutch dairy farms. The average herd size was 64 +or- 16 cows. The data were collected during a routine herd health and production control programme. The cumulative 100-DIM (days in milk) production in the previous lactation of lame cows was higher and the culling rate lower than that of the controls. The 100- and 270-DIM production of the cows with a sole ulcer was higher than that of the control cows. There was no difference in 100- and 270-DIM production between cows with a lameness diagnosis other than sole ulcer and the controls. Lameness prolonged the interval from calving to first service and the interval from first service to conception. The pregnancy rate at first service was not affected by lameness..RE: 32 ref.; SC: CA; VE; ZA; 0I; BE; 0VSource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=20&issue=4&spage=249&pages=249-259&date=1994&title=Preventive%20Veterinary%20Medicine&atitle=The%20effects%20of%20lameness%20on%20reproductive%20performance%2c%20milk%20production%20and%20culling%20in%20Dutch%20dairy%20farms.&aulast=Barkema&pid=%3Cauthor%3EBarkema%2c%20H%20W%3bWestrik%2c%20J%20D%3bKeulen%2c%20K%20A%20S%20van%3bSchukken%2c%20Y%20H%3bBrand%2c%20A%3C%2Fauthor%3E%3CAN%3E19942216877%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
Herd level measures of health and productivity in Prince Edward Island dairy herds
No full textHerd level measures of health and productivity in Prince Edward Island dairy herds, computed monthly over a 4 year period, were evaluated. Descriptive statistics for 11 key measures of health and productivity were computed. The parameters cover the areas of milk production, reproductive performance, mastitis and milk quality. Many parameters exhibited considerable within-herd variation, suggesting that monthly values must be converted into a rolling average before they could be used reliably. Six of the 11 parameters exhibited a distinct seasonal pattern and seasonally adjusted values were obtained for those parameters. In general, the seasonally adjusted values had smaller within-herd variation than the non-adjusted values. For each parameter, the month-to-month variability was determined for both the original monthly values and monthly values of a 3 month weighted rolling average. The 90th percentiles of these month-to-month changes were used as a threshold to identify 'large' fluctuations in a herd's performance. Guidelines for the interpretation of each of the 11 parameters are presented..RE: 15 ref.; SC: BE; ZA; 0N; AG; VE; CA; 0U; 0I; 0V; 0A; 0DSource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=16&issue=4&spage=255&pages=255-261&date=1993&title=Preventive%20Veterinary%20Medicine&atitle=Herd%20level%20measures%20of%20health%20and%20productivity%20in%20Prince%20Edward%20Island%20dairy%20herds.&aulast=Dohoo&pid=%3Cauthor%3EDohoo%2c%20I%20R%3bRuegg%2c%20P%20L%3C%2Fauthor%3E%3CAN%3E19932289375%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
Somatic cell count patterns in Prince Edward Island dairy herds
No full textPattern diagnosis (establishing a diagnosis of a herd problem based on the distribution of health events within that herd) is only possible if information about the expected, or 'normal' distribution is available. This study examined the distribution of somatic cell count (SSC) patterns in Prince Edward Island dairy herds. The main features were an overall prevalence of elevated counts (more than 200 000 cells/ml) of 29%, a steady increase in prevalence estimates across the 3 age groups examined (lactation 1, lactations 2-4 and lactations 5+) and relatively constant prevalence estimates through the first 200 days of lactation. The overall new infection risk was 15% with similar age and stage-of-lactation patterns (as were observed for prevalence estimates). The overall elimination risk was 22% and it declined across all age and stage-of-lactation groups. Based on the variability of parameter estimates from a number of test dates, at least 1 year's data (10-11 tests) is recommended to be used to evaluate patterns in a dairy herd of 40-60 cows in this region of Canada..SC: CA; VE; ZA; 0I; BE; 0V; 0DSource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=&issue=&spage=53&pages=53-65&date=1993&title=Preventive%20Veterinary%20Medicine&atitle=Somatic%20cell%20count%20patterns%20in%20Prince%20Edward%20Island%20dairy%20herds.&aulast=Dohoo&pid=%3Cauthor%3EDohoo%2c%20I%20R%3bMorris%2c%20R%20S%3C%2Fauthor%3E%3CAN%3E19932281623%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
Disease, production and culling in Holstein-Friesian cows. II. Age, season and sire effects
No full textEffects of age, season and sire on the occurrence of common diseases of Holstein-Friesian cows were evaluated in a two and a half year study. The data were from 2875 lactation records from 2008 cows in 32 commercial dairy herds within a 50 mile radius of Guelph, Ontario. Age patterns for all disease conditions were determined. Linear increases with age were observed for milk fever, mastitis requiring local therapy only, cystic ovaries and foot and leg problems. Quadratic relationships with age were observed for ketosis (clinical and subclinical), mastitis requiring systemic therapy, subclinical mastitis, dystocia, respiratory diseases and traumatic reticulo-peritonitis. No consistent age patterns were found for retained placentas, reproductive tract infections, abomasal displacements, teat injuries, digestive disorders and abortions. Seasonal patterns showed peaks in the risk of ketosis and cystic ovaries during the winter, and in the risk of teat injuries in the late winter or early spring. Seasonal patterns, more complex than a simple unimodal pattern, were observed for mastitis requiring local therapy only, traumatic reticulo-peritonitis and abortions. Heritability of 9 disease conditions was low or zero, with the exception of clinical ketosis..RE: 46 ref.; SC: ZA; CA; VE; BE; 0V; 0I; 0D; 0ASource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=2&issue=5&spage=655&pages=655-670&date=1984&title=Preventive%20Veterinary%20Medicine&atitle=Disease%2c%20production%20and%20culling%20in%20Holstein-Friesian%20cows.%20II.%20Age%2c%20season%20and%20sire%20effects.&aulast=Dohoo&pid=%3Cauthor%3EDohoo%2c%20I%20R%3bMartin%2c%20S%20W%3bMcMillan%2c%20I%3bKennedey%2c%20B%20W%3C%2Fauthor%3E%3CAN%3E19842248273%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
Environmental and managerial risk factors of intramammary infection with coagulase-negative staphylococci in Ohio dairy herds
No full textA stratified random sample of Ohio dairy herds was studied to relate herd management and environmental conditions to the prevalence of intramammary infection with coagulase-negative staphylococci. Management and environmental conditions were assessed by investigator observation and by interview with the dairy producers. Separate analyses for each of 70 management and environmental independent variables identified many potential disease determinants. Analysis of covariance models were developed to predict the prevalence of coagulase-negative staphylococci. The first model used 7 model degrees of freedom, had an Rsuperscript 2 of 0.62, and included the following independent variables: use of a cloth for washing cows, use of a hypochlorite- or iodine-based post-milking teat dip, a population of milking cows less than 50, the amount of bedding provided, use of free stall housing, an interaction between a small herd size and the amount of bedding provided and an interaction between the use of free stalls and the type of post-milking teat dip. The second model had an Rsuperscript 2 of 0.54 and was reduced to 5 model degrees of freedom by exclusion of the variables for use of free stalls and the interaction between free stalls and type of post-milking teat dip..RE: 27 ref.; SC: BE; VE; AG; CA; ZA; 0I; EC; 0V; 0DSource type: Electronic(1) http://upei-resolver.asin-risa.ca?sid=SP:CABI&id=pmid:&id=&issn=0167-5877&isbn=&volume=14&issue=1-2&spage=129&pages=129-142&date=1992&title=Preventive%20Veterinary%20Medicine&atitle=Environmental%20and%20managerial%20risk%20factors%20of%20intramammary%20infection%20with%20coagulase-negative%20staphylococci%20in%20Ohio%20dairy%20herds.&aulast=Bartlett&pid=%3Cauthor%3EBartlett%2c%20P%20C%3bMiller%2c%20G%20Y%3bLance%2c%20S%20E%3bHeider%2c%20L%20E%3bAnderson%2c%20C%20R%3C%2Fauthor%3E%3CAN%3E19932278534%3C%2FAN%3E%3CDT%3EJournal%20article%3C%2FDT%3
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