Maurice E. White

Path model of individual-calf risk factors for calfhood morbidity and mortality in New York Holstein herds☆

Abstract A multivariable path model (based on field data) of the interrelationships between individual-calf management practices and calfhood morbidity and mortality was constructed. Data were from 1171 heifer calves who lived greater than 24 h and were kept as replacements on 26 farms in the vicinity of Cornell University between July 1983 and 30 April 1985. Outcomes of interest were the first occurrence of the following clinical signs as diagnosed by farmers on standardized check-off forms: scours/diarrhea within 14 days of birth and from 15 to 90 days of age; dull, listless, droopy ears or off feed within 90 days of birth; cough, runny nose or eyes or trouble breathing within 90 days of birth; death prior to 90 days of age. Risk-factor data were based on information collected on standardized check-off sheets for each individual calf. Place of birth, calving events, colostrum administration and initial housing, as well as any prophylactic or other treatments, were recorded by the person caring for the calf. Logistic regression was used to estimate the path coefficients (i.e. relative risks: RRs). Time ordering of morbidity and mortality variables inherent in the data were used to construct the hypothesized model. Management appeared to affect directly and indirectly (via scours within 14 days of birth, scours from 15 to 90 days of age and dullness) the risk of respiratory illness. Being born in loose housing increased risk of both scours within 14 days of birth and scours from 15 to 90 days of age. Calves tied versus being housed in group pens were at increased risk of scours within 14 days of birth (RR=1.5). Calves of first-calf heifers were at increased risk of respiratory illness (RR=1.5), and calves whose dams were vaccinated against Escherichia coli were at decreased risk of death (RR=0.2). Calves with scours within 14 days of birth, dullness and scours from 15 to 90 days of age were at increased risk of respiratory illness (RR=2.5, 7.7 and 3.1, respectively). Although respiratory illness had the largest direct RR for death, dullness actually had a greater effect on risk of death because of its additional indirect association through respiratory illness (dullness increased risk of respiratory illness which then increased risk of death).

Descriptive epidemiology of calfhood morbidity and mortality in New York holstein herds

Abstract A prospective cohort study was done of 1171 Holstein heifer calves born from July 1983 to 30 April 1985 and kept to be raised as replacements in 26 commercial dairy herds in the vicinity of Cornell University. The objectives were to examine the interrelationships of management with morbidity and mortality at both the individual and herd level, and the long-term effects of morbidity on survical. The study population, data collection and processing methods, and the descriptive epidemiology (e.g. age and temporal distributions) of calfhood morbidity, mortality and treatments are described. The clinical signs (as diagnosed by farmers on standardized check-off forms) studied were: scours/diarrhea within 14 days of birth and from 15 to 90 days of age; dull, listless, droopy ears, or of feed within 90 days of birth; cough, runny nose or eyes, or trouble breathing within 90 days or birth; death prior to 90 days of age. The crude incidence rates of scours within 14 days of birth, scours from 15 to 90 days of age, dullness, respiratory illness and death were 9.9, 5.2, 7.7, 7.4 and 3.5 per 100, respectively, for the period of study. The only seasonal effect on incidence was for scours within 14 days of birth (which was higher in winter compared to summer across both years of the study). The incidence rates of scours from 15 to 90 days of age, dullness and respiratory illness were higher in the first year of the study compared to the second year; there was no effect of season on these outcomes. The mortality rate within 90 days of birth was not related either to year of study or season. The median ages at occurence of scours within 14 days of birth, scours from 15 to 90 days of age, dullness, respiratory illness, and death were 6, 30, 16, 25 and 28 days, respectively. Risks of clinical signs were highest in the first week of life, while risk of death was highest in the third week. Calves with only scours within 14 days of birth or only scours from 15 to 90 days of age were treated primarily with oral electrolytes, oral antibiotics, and restriction of milk consumption. Calves with only dullness or only respiratory illness were treated primarily with intramuscular antibiotics. The median herd incidence rates of scours within 14 days og birth, scours from 15 to 90 days of age, dullness, respiratory illness and death were 5, 0, 0, 0 and 0 per 100, respectively, during the periof of the study.

Effect of calfhood morbidity on age at first calving in New York Holstein herds

Abstract The effect of calfhood morbidity on age at first calving was investigated in 948 heifer calves in 21 herds in the vicinity of Cornell University. Heifers were born from July 1983 to April 1985 and neither died nor were sold prior to 90 days of age. All calvings occurred on or before 31 May 1987. The specific calfhood morbidity variables of interest were the first occurrences of the following clinical signs as diagnosed by farmers on check-off forms: scours/diarrhea within 14 days of birth and from 15 to 90 days of age; dull, listless, droopy ears, or off of feed within 90 days of birth; cough, runny nose or eyes, or trouble with breathing within 90 days of birth. The Kaplan-Meier product-limit life-table technique and Coxs proportional hazards model were used to evaluate the effect of calfhood morbidity on the age distribution of first calving. Season and year of birth were included (forced) into the Coxs proportional hazards model as possible confounding variables. The model was stratified on herd (allowing a different survival function for each herd) in order to account for herd effects. The final Coxs proportional hazards model included season and year of birth, signs of respiratory illness within 90 days of birth and dullness within 90 days of birth. Heifers without respiratory illness as calves were twice as likely subsequently to calve and calved 6 months earlier when compared to those with respiratory illness as calves. Heifers with dullness as calves were 1.6 × more likely to calve and calved 2 months earlier when compared to calves without dullness as calves.

Prevalence of Giardia spp. and Cryptosporidium spp. on dairy farms in southeastern New York state.

A prevalence study was designed to determine the presence of Cryptosporidium spp. and Giardia spp. in the soil of 37 dairy farms in southeastern New York state. A sampling design was developed and used to collect soil samples from these farms. Areas on the farms which were considered to be potential sources of contamination to the environment were evaluated quantitatively using a multidimensional scale. This scale included factors which could have the potential to contribute to the risk of contamination of the environment with Giardia or Cryptosporidium. In addition, the runoff pathway from these areas was identified and sampling points along that pathway were determined. Using a sampling grid, sampling sites were determined and soil samples collected and analyzed individually for the following: presence of Giardia and Cryptosporidium, pH, gravimetric moisture content, and volumetric moisture content. Out of 782 soil samples, 17% were positive for Cryptosporidium and 4% were positive for Giardia. The pH of the soil ranged from 3.7 to 9.8 with a mean of 7.0. There was a significant association between the pH and the likelihood of detecting Cryptosporidium spp. As the pH increased, the likelihood of detecting an oocyst decreased. Gravimetric moisture content had a mean of 40% and a range from 7 to 86%. There was a significant association between the gravimetric moisture content and the likelihood of detecting Giardia in soil samples.

The relationship of calfhood morbidity with survival after calving in 25 New York Holstein herds.

The association of owner-diagnosed calfhood diseases with the length of herd life after calving was evaluated using data collected prospectively over a ten-year period in 25 New York Holstein dairy herds. Herds selected for the study were milking between 35 and 200 Holstein cows, used dairy herd improvement records, bred cows by artificial insemination unless they needed three or more services, and had regularly-scheduled herd health visits by clinicians from the Cornell University College of Veterinary Medicine. Owners recorded occurrences of dullness, respiratory disease, and scours from birth through 90 days of age for all heifer calves that lived at least 24 h and were to be kept as replacements. Milking herd life was measured as the difference between the age at first calving and the age at death or sale. Data on cows sold when the herd went out of business or still in the herd at the end of the study were censored observations. Coxs proportional hazards model was used for statistical analysis of the data. Controlling for age at first calving, study month of birth, and sire predicted difference for milk, there was no statistically significant association of calfhood morbidity with length of herd life. The estimated hazard rate ratios for leaving the milking herd and 95% confidence intervals for dullness, respiratory disease, and scours within 90 days of birth were 1.3 (0.9, 1.9), 0.9 (0.6, 1.3), and 1.0 (0.8, 1.3), respectively. Dullness was the only disease category with an estimated hazard rate ratio greater than 1, and although it was not statistically significant, may warrant evaluation in future studies of long term effects of calfhood morbidity.

Effects of calfhood morbility on long-term survival in New York Holstein Herds

Abstract The effect of calfhood morbility on long-term survival (i.e. not dying or being sold) was evluated in 1069 heifer replacement calves in 24 herds in the vicinity of Cornell University. These calves were born between July 1983 and 30 April 1985, and were alive at 90 days of age. The specific calfhood morbility variables of interest were the first occurrence of the following clinical signsn as diagnosed by farmers on standardized check-off forms: (1) scours/diarrhea within 14 days of birth and from 15 to 90 days of age; (2) dull, listless, droopy ears or off feed within 90 days of birth; (3) cough, runny nose or eyes, or trouble breathing within 90 days of birth. Outcomes of interest were (1) death, (2d (2) sale and (3) combined death and sale (exit) after 90 days of age and before 11 February 1986. Age-specific incidence rates and survival functions for the outcomes of interest were calculated using life-table techniques. The effects of the morbility variables on survival were modeled using Coxs proportional hazards model. The crude incidence rates of death and sale after 90 days of age for the study period were 2.5 and 5.1 per 100, respectively. Age-specific mortality rates after 90 days of age indicated a rise in mortality at ∼ 1 year of age. The age-specific incidence rate of sale after 90 days of age increased between 1 and 2 years of age (corresponding to the age at which farmers start reducing heifer numbers to the number needed for replacements). There were no significant effects of season and associated year of birth (birth cohort effect) on the survival distributions of death and sale after 90 days of age, although there was on exit after 90 days of age. The only illness related to survival was dullness within 90 days of birth, which increased the hazards rate for death after 90 days of age 4.3-fold above that for heifers without dullness within 90 days of birth, after adjusting for herd and season and associated year of birth.

The relationship of the interval from breeding to uterine palpation for pregnancy diagnosis with calving outcomes in holstein cows.

This study used data collected prospectively at 32 dairy herds to examine the effect of interval from breeding to uterine palpation for pregnancy diagnosis on calving interval and likelihood of calving. Multivariable statistical models were used to control for other factors that were significantly associated with the outcomes of interest. Cows diagnosed pregnant from 30 to 36 d post breeding had 2-wk longer calving intervals than cows palpated at later intervals. The interval from breeding until a cow was diagnosed open had a significant positive association with the calving interval. The interval to palpation was not associated with the probability of remaining in the herd to calve when controlling for the effects of herd, season of freshening, number of services, days to first service and mature equivalent milk production. Among cows diagnosed pregnant, 3.4% subsequently were bred and 1.5% were diagnosed open by palpation at a later date. About 5% of the cows diagnosed open calved at a time consistent with being pregnant when the diagnosis was made.

Detection of Cryptosporidium parvum and Cryptosporidium muris in soil samples

Abstract The flotation procedure for the detection of Cryptosporidium parvum and Cryptosporidium muris oocysts in feces was adapted for use on soil samples. Soil samples were seeded with known amounts of purified C. parvum or C. muris oocysts and Cryptosporidium spp.-free bovine feces. The limit of detection for this procedure was determined at different levels of inoculation for each species. At each level of inoculation, 30 control samples were processed and the observer was blind to the status of the sample. All samples were examined for the presence of Cryptosporidium spp. oocysts using phase-contrast microscopy. The samples were seeded with the following estimated counts of C. parvum oocysts: 1000/g, 1250/g, and 1500/g. These levels had sensitivities of 88%, 90%, and 93%, respectively. All inoculation levels had a specificity of 100%. Thirty additional samples were inoculated with C. muris and the limit of detection was found to be 76 oocysts/g sample, with a sensitivity of 97% and a specificity of 100%.

Path model of herd-level risk factors for calfhood morbidity and mortality in New York Holstein herds

Abstract A multivariable path model of the interrelationships between herd-management policies and herd-level calfhood morbidity and mortality was constructed. Data were from 25 farms in the vicinity of Cornell University, and comprised records from all 962 heifer calves born between 1 November 1983 and 30 April 1985 who lived longer than 24 h and were kept to be raised as replacements. Outcomes of interest were herd-season-year cumulative incidences of the following clinical signs as diagnosed by farmers and recorded on check-off forms: scours/diarrhea within 14 days of birth and from 15 to 90 days of age; dull, listless, droopy ears or off feed within 90 days of birth; cough, runny nose or eyes, or trouble breathing within 90 days of birth; death prior to 90 days of age. Herd-management risk-factor data were based on information from a personal-interview questionnaire administered by the senior author, and were measures of policy rather than of what individual calves actually experienced. Random-effects logistic regression (logistic-normal regression) was used to model incidence rates and to account for the extra-binomial variation due to heterogeneity of disease risk between herds. Herd-management policies directly and indirectly ‘affected’ the herd cumulative incidences of morbidity and mortality. Farms reporting that calves had periodic, or no, access to water (compared to continuous availability) had less scours from 15 to 90 days of age and less dullness. Damp (versus dry) bedding, tying calves ((by a collar and tether) versus not tying calves)), use of individual-calf hutches, and feeding milk once daily (versus twice daily) all ‘increased’ the chance of scours within 14 days of birth. Use of individual-calf stalls ‘increased’ the chance of scours from 15 to 90 days of age, but ‘decreased’ the chance of mortality. Feeding high-moisture ear corn to calves ‘increased’ the chance of scours from 15 to 90 days of age, suggesting that some of the later scours were of nutritional origin. Scours prior to 14 days of age and dullness (but not later scours) ‘increased’ the chance of respiratory illness. Only respiratory illness directly ‘increased’ the chance of mortality. Scours prior to 14 days of age and dullness were related to mortality indirectly via respiratory illness. Scours from 15 to 90 days of age were not related to mortality.

Association of oxidative stress with motor neuron disease in horses.

OBJECTIVE To investigate the influence of oxidative stress in terms of antioxidant capacity and lipid peroxidation on the probability of motor neuron disease (MND) in horses. ANIMALS 88 horses with MND (cases) and 49 controls. PROCEDURES Blood samples were collected from all horses enrolled, and RBCs and plasma were harvested. Activity of the enzyme erythrocytic superoxide dismutase 1 (SOD1) was determined in the RBCs. Plasma concentrations of α-tocopherols and β-carotenes and activity of glutathione peroxidase were also evaluated. Degree of lipid peroxidation was measured by determining plasma concentrations of lipid hydroperoxides. Differences were evaluated between horse groups. RESULTS Cases had lower erythrocyte SOD1 activity than did controls, but the difference was not significant. On the other hand, plasma vitamin E concentrations differed significantly between groups, with the cases having lower concentrations. Neither plasma vitamin A concentration nor glutathione peroxidase activity differed between groups; however, cases had significantly higher concentrations of lipid hydroperoxides (18.53μM) than did controls (12.35μM). CONCLUSIONS AND CLINICAL RELEVANCE Horses with MND differed from those without MND by having a lower plasma concentration of vitamin E and higher concentrations of lipid hydroperoxides. Results parallel the findings in humans with sporadic amyotrophic sclerosis and provide evidence supporting the involvement of oxidative stress in the 2 conditions.