William E. Marsh

Lifetime reproductive performance in female pigs having distinct reasons for removal

This study describes the reasons for removal of female pigs distributed across parity categories, and evaluates how parameters of lifetime productivity differ for females having distinct removal reasons. The study analyzed lifetime records ® from 7973 females. Those records were obtained from 28 herds from the PigCHAMP research database having high-quality data during a five-year period. Female life expectancy corresponded to 3.3 parities at removal or 1.6 years spent in the breeding herd. The most common removal reason was culling attributed to reproductive disorders (33.6%), followed by culling for sub-optimal litter performance (20.6%). Sows culled for old age (8.7% of the removals) spent proportionally fewer days in non-productive periods, and produced more weaned pigs annually and over a lifetime than females removed for other reasons (P , 0.05). In contrast, females culled for reproductive failure accumulated the largest proportion of non-productive days (NPD) during the time spent in the breeding herd, and produced the fewest weaned pigs per lifetime and per year (P , 0.05). These findings indicate that culling for reproductive reasons is more common among low-parity females, which suggests that minimisation of NPD at early reproductive cycles is crucial to optimise female lifetime reproductive efficiency.

Descriptive epidemiology of morbidity and mortality in Minnesota dairy heifer calves

Abstract A prospective study was carried out on 845 heifer calves born during 1991 on 30 Holstein dairy farms in southeast Minnesota. The objectives of the study were to describe the epidemiology of morbidity and mortality in dairy calves from birth to 16 weeks of age (with an emphasis on respiratory disease), to examine individual calf and herd management practices as risk factors for calf morbidity and mortality, and to validate producer diagnosis of mortality. Incidence rates for all morbidity, enteritis, and pneumonia were 0.20, 0.15, and 0.10 cases per 100 calf-days at risk for the period of the study. Risk of enteritis was highest in the first 3 weeks of life, with pneumonia risk highest at 10 weeks of age. Case fatality rates averaged 11.8%, 17.9%, and 9.4% for all diagnoses, enteritis, and pneumonia, respectively. Average daily rates of gain from birth to 16 weeks of age differed between farms that had inadequate calf housing (0.8 kg day−1) versus those with adequate calf housing (1.0 kg day−1). Approximately half of the calves in the cohort (418) had blood samples taken monthly from birth until 16 weeks of age. Of the calves sampled, only 19 calves showed a four-fold rise in serum titers to respiratory viruses. Sixteen calves seroconverted to BVDV, two calves to IBRV, and one calf to PI3 virus. Of 98 calves less than 10 days of age tested for adequacy of passive transfer, 35 (35.7%) had serum immunoglobulin levels of less than 800 mg dl−1. There were no significant differences in mortality or morbidity between calves that had adequate passive transfer and those that did not. The incidence of mortality was 0.08 deaths per 100 calf-days at risk; 64 calves died during the 16 months of the study. The risk of death was highest at 2 weeks of age. Enteritis was the most common cause of death (28 deaths, 44% of all deaths) followed by pneumonia (19 deaths, 30% of all deaths). Comparing producer diagnosis of mortality with necropsy results yielded sensitivities of 58.3% and 56% and specificities of 93% and 100% for producer diagnoses of enteritis and pneumonia, respectively. The kappa statistic comparing producer diagnosis with necropsy result was 0.47. The most common pathogens isolated from calves that died of enteritis were rotavirus (five calves), and Escherichia coli (four calves). Pathogens isolated from pneumonic lungs included Pasteurella multocida (three calves), Haemophilus somnus (three calves), and Pasteurella haemolytica (one calf).

Influence of lactation length on sow productivity

Abstract Associations between sow lactation length, the productivity of individual sows at their subsequent farrowings, and annual breeding productivity were analyzed using a data base including 14925 farrowing records from 39 swine herds. Longer lactation lengths were associated with higher subsequent litter sizes (both total-born and born-alive), shorter weaning-to-service intervals, longer farrowingto-service intervals, and longer farrowing-to-farrowing intervals ( P P > 0.2). The observation that reducing lactation length from 30 to 17 days does not significantly affect pigs per sow per year is attributed to the compensatory effects of shorter lactation on pigs born per litter and litters per sow per year. This range of lactation length is commonly employed by American swine producers and appears to incorporate the optimal range for breeding herd productivity as measured in terms of pigs weaned/sow/year. Nevertheless, the optimal lactation length for an individual herd likely will be influenced by its particular management, environmental and financial characteristics.

Validation of producer-recorded causes of preweaning mortality in swine

Abstract This study examined the accuracy of producer-recorded causes of preweaning mortality on 13 commercial swine farms using a computerized recording system. All stillborn piglets and those born alive but dying between birth and weaning were collected over 6–8-week period and stored frozen until necropsy. Reason for death, piglet age, date of death and antemortem history, when known, were recorded by producers for 1063 dead piglets. There were 916 piglets born alive but dying before weaning, 146 stillborn piglets and one mummified piglet. Gross observations at postmordem examination were used to classify piglets into the following major categories of mortality: low viability, trauma, scours, deformed, infection, stillborn, and other. The relationship between producer-recorded causes of death and causes established at necropsy was expressed in terms of sensitivity and specificity. Sensitivity was the proportion of piglets correctly classified within a category, using necropsy results as the gold standard. Specificity was the proportion of piglets correctly excluded from a category. The sensitivity and specificity of producer assessment of the death causes varied with the mortality category. Within each category, variations in sensitivity and specificity also were noted among age groups. The results demonstrated that without validation of data-recording accuracy, retrospective and prospective studies using producer diagnosis of causes of death in suckling piglets are likely to be invalid.

Management practices and risk factors for morbidity and mortality in Minnesota dairy heifer calves

This prospective study involved 845 Holstein heifer calves born during 1991 on 30 dairy farms in southeast Minnesota. The objectives of the part of the study reported here were to examine relationships between management practices and incidence of morbidity and mortality at both herd and individual-calf levels. A survey administered by the investigators identified the herd management practices. Check-off forms completed by cooperating producers captured the individual-calf risk factors. Data collected included events surrounding each calfs birth as well as treatments and disease diagnoses for each heifer calf. Outcomes of interest were any occurrence of enteritis, pneumonia, or death between birth and 16 weeks of age. Time, place and date of birth, ease of birth, colostrum administration and any other treatments at birth, housing and any other treatments were the risk factors of interest. The overall morbidity rate for the study was 0.2 calves treated per 100 calf-days at risk (range 0-0.8, standard deviation 0.2), while the rates for scours and pneumonia were 0.15 cases per 100 calf-days at risk (0-0.7, ± 0.2) and 0.10 (0-0.7, ± 0.2) cases per 100 calf-days at risk, respectively. The mortality rate for the study period was 0.08 deaths per 100 calf-days at risk (0-0.3, ± 0.08); 64 heifers (7.5%) died during the study. Mean average daily weight gains for heifers from birth to 16 weeks of age was 0.82 kg day−1 for all farms (0.45–1.1, ± 0.2). In general, stated herd management practices were practiced at the individual-calf level. Several herd management practices altered the outcomes of interest. For example, the feeding of a coccidiostat to preweaned calves increased the herd risk of pneumonia (relative risk, 3.38; 95% CI 1.34–8.50). The feeding of a vitamin A-D-E supplement to preweaned calves exerted a protective effect against scours (0.35, 0.13–0.93). Managing group pens for weaned calves in an ‘all-in, all-out’ fashion rather than in a continuous flow system contributed to a farm having an average daily rate of gain that was above the median (3.06, 1.34–6.97). The Cox proportional hazards model was used to describe relationships between risk factors and the outcomes of interest. Calves that required assisted delivery were at an increased risk of developing enteritis sooner than those that were born without assistance. No other risk factors had a significant effect.

Individual cow risk factors for clinical lameness in lactating dairy cows

Abstract A case-control study investigating relationships between clinical lameness and individual-cow (within herd) risk factors was performed in 17 Minnesota and Wisconsin dairy herds. Cases were defined as lactating cows found lame by either of two observers during farm visits in the summer of 1989 and spring of 1990 using a uniform scoring system. A single control cow (matched by herd, season, parity, and stage of lactation) was selected for each case at each visit. Assessments of body weight, body condition, dorsal claw angles, and limb lesions were made for each case and control animal. Conditional logistic regression analysis revealed positive associations between prevalent clinical lameness and heavier body weight, lower body condition score, and shallower slope of rear lateral claw angle. Lesions associated with clinical lameness included non-tarsal rear limb superficial swellings, abnormal hoof overgrowth (including corkscrew claw), and limb lacerations. Superficial tarsal swellings, intra-synovial tarsal swellings, and carpal swellings were not associated with clinical lameness.

Relationship of production to reproductive performance in Ontario dairy cows: herd level and individual animal descriptive statistics.

Data were collected on reproductive, health and production events in 45 dairy herds distributed throughout southwestern and eastern Ontario. The data were collected between July 1990 and July 1993. The herds were serviced by 11 different veterinary practices. Herd size ranged from 19 to 231 lactating cows, but 90% of the herds consisted of fewer than 125 milking cows. Mean and median actual milk yields per cow per day were 46.0 and 52.3 lbs, respectively, with a minimum of 21.3 and maximum of 67.8 lbs. Mean and medium adjusted corrected milk yields were 56.0 and 62.3 lbs, reflecting mean and median average days in milk of 199.0 and 198.5 d, respectively. Mean and median days in milk at the first estrus were 85.1 and 83.9 d, respectively, at first service 94.0 and 88.9 d, and at conception 126.3 and 115.5 d. Mean and median percentages of days open > 120 were 27.7 and 23.1%, respectively. The mean estrus detection rate was 48.3%, with a minimum of 28.4% and a maximum of 64.2%. The mean first service conception rate was 48.2%, with a minimum of 27.0% and maximum of 72.1%. The mean overall conception rate was 46.7%, with a minimum of 29.8% and a maximum of 70.7%. Mean and median lactation lengths were 341.1 and 338.5 d and the mean and median average dry days were 62.0 and 67.0, respectively. The mean lactational removal rate was 20.6%, with a range of 4.3 to 40.5%. Reasons for culling were available for 1381 cows. Low production accounted for 23.7 % of the cullings; reproductive reasons, 20.6 %; dairy sales, 13.4%; mammary problems, 12.8%; and lameness, 9.9%. Lactational incidence rates for diseases were lower than previously reported for Ontario dairy herds. The most commonly used therapeutic agents were GnRH (10.5%) and PGF (11.7%).

Evaluation of the monitoring of papular dermatitis lesions in slaughtered swine to assess sarcoptic mite infestation

We investigated the association between the presence of papular dermatitis and sarcoptic mite infestation in pigs slaughtered in southern Minnesota. Following dehairing, a sample of 30 pigs from each of 50 herds was inspected for papular dermatitis lesions. Herds were selected after being categorized into one of five categories according to the prevalence and severity of dermatitis lesions. Herd infestation with sarcoptic mange was determined by recovery of mites from ear scrapings of slaughtered pigs and also by survey of producer opinion. Mite infestation was detected in 28 herds (56%) and 215 of 1500 pigs (14%). Considerable variability in prevalence of positive scrapings, ranging from one pig (3%) to 19 pigs (63%), was found among infested herds. Prevalence of mite infestation was positively associated with severity of papular dermatitis lesions in groups. For individual pigs, estimates of the specificity of localized lesions ranged from 0.70 to 0.90. Generalized lesions appear highly specific (> 0.98) for sarcoptic mite hypersensitivity. Generalized lesions occurred in 36.7% of pigs from herds confirmed to be infested, compared with 0.4% of pigs in herds confirmed free from mange. Our date indicate that monitoring of dermatitis lesions in slaughtered pigs might be a useful test for sarcoptic mange in the Midwest, USA.

Downer cow occurrence in Minnesota dairy herds

Abstract The report contains survey data about occurrence of the downer cow syndrome in 723 dairy herds with 34 656 cow years at risk. Herds were categorized by breed, registration status, and type of housing. For the purpose of this survey, downer cows were defined as being recumbent on the sternum for > 24 h for no obvious reason. The overall incidence of downer cows in the sample was 21.4 1000 cow years at risk. The overall outcome of downer cases was that 33% recovered, 23% were slaughtered, and 44% died. Further specification of data by breed, registration, and time down before recovery, slaughter of death is noted in the text. Owners perceived that downers were high producers (48%) or average producers (46%), with only 6^ being low producers. They reported that 58% of cases occurred within one day of parturition while an additional 37% occurred during the first 100 days of lactation. The number of downers associated with dystocia was 24%, but this was 41% of the cases which went down within one day of calving. The highest incidence of downer cases was during the three coldest months (December–February) when 39% of the cases occurred. In contrast only 16% of cases occurred during the spring months (April–June). A majority of respondents (75%) had experience with hip lifting devices. Of this group 71% found them to be useful for management of downer cows.

Internal consistency of preweaning mortality data collected by swine producers

Abstract An approach to assess the internal consistency of preweaning mortality data was developed. Retrospective information from 337 North American swine herds entered in the computerized record system PigCHAMP® was used. The production data were evaluated using a series of equations testing the within-litter consistency of the following production parameters: number of pigs born alive, number of pigs net fostered (number of pigs fostered on minus those fostered off), number of piglets weaned from each litter and number of piglets recorded dead by the producer. The study was based on the premise that producers are accurate in recording the number of pigs born alive and the number of pigs weaned for each litter. The equations used and other criteria led to the rejection of almost 84% of all herds included in the original data set.