Descriptive epidemiology of morbidity and mortality in Minnesota dairy heifer calves

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).     

A path model of factors influencing morbidity and mortality in Ontario feedlot calves.

The principles of path analysis and causal modelling are discussed. Path analysis was applied to three data sets to assess the relationship between group characteristics (number per group and "mixing" subgroups of cattle, feeding-management of the group and processing factors (vaccination and prophylactic antimicrobials) and subsequent morbidity and mortality in feedlot cattle. The major findings agree with previously reported results but the timing and pathways of the effects are elaborated. In general, morbidity in week 1 was correlated with morbidity in week 2, which was correlated with morbidity in weeks 3-5. The same was generally true for mortality. In general, morbidity was not strongly correlated with mortality. Lots (unmixed groups) did not arrive in better condition, but experienced fewer subsequent health problems than mixed groups. (Silage-fed lots appeared to do poorly, however this was apparently due to the positive association between lots and vaccination, the latter being detrimental to mortality rates.) The more cattle per group, the greater the health problems in weeks 3-5 postarrival. Prophylactic antimicrobials in the water supply on arrival lead to increased health problems in the three to five week postarrival period. Antibiotic containing starter rations had a beneficial effect on health status in this period. This effect appeared to be partly due to delaying making silage the major ration component in silage-fed cattle receiving antimicrobial containing starter rations. Vaccination against respiratory disease in either of the first two weeks postarrival had detrimental direct and indirect effects on subsequent health status. Vaccination during weeks 3-5 postarrival was not significantly related to health status in that period.     

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 calf's 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.     

The present epizootological situation in intensively bred cattle in relation to the morbidity and mortality of calves during their rearing

The rise and mass incidence of intestinal and respiratory infections in calves kept in large herds depend on a joint influence of infective agents and numerous endogenous and exogenous factors, mostly with non-specific action. Therefore, purely medical approach fails to provide efficient prevention. Detailed epizootological analysis is needed for taking actual measures; the analysis should concern potential respiratory and intestinal pathogens and should also cover the persistent infections such as IBR, BVD-MD and others. The immunological profile of herd, very unfavorable with the high culling rate, will improve as a result of the introduction of a purpose-oriented vaccination programme, higher level of colostral nutrition, and separate rearing of calves, isolated from the dams, in calf houses managed by the all-in-all-out system.     

A mail survey of factors associated with morbidity and mortality in feedlot calves in southwestern Ontario.

The design and results of a mail survey of a simple random sample of southwestern Ontario feedlot owners are presented. The survey provided general data about management of feedlot calves and the association between a number of factors and disease and/or death rates. The number of calves purchased was related positively, in a linear manner, to mortality and morbidity rates. Increased levels of morbidity and mortality were noted when the ration was changed to corn silage from dry-hay within the first month after arrival. However, it was not clear whether the ration changes preceded or followed increased rates of morbidity and mortality. Prophylactic levels of antimicrobials in the water supply were associated with increased death losses. Shipping cattle by truck, rather than train, was associated with decreased rates of disease. Processing factors, including using vaccines against respiratory disease, were not associated significantly with mortality or morbidity. It was concluded that reducing the number of calves, to approximately 100 per group, not changing the ration to silage within the first month and not using antibiotics in the water supply on arrival could significantly reduce disease and death losses.     

Factors associated with morbidity,mortality, and growth of dairy heifer calves up to 3 months of age

Calfhood disease is an important problem on many dairy operations that can have substantial effects on heifer survival and productivity, and has economic and welfare impacts. Neonatal calf diarrhea (NCD) and bovine respiratory disease (BRD) are the most common causes of morbidity and mortality in young dairy cattle. The objective of this observational study was to investigate factors associated with the risks of morbidity and mortality, and with growth, in commercial dairy heifers calves. A total of 2874 heifer calves from 19 commercial dairy farms in Minnesota and Ontario were enrolled at 1–7 days of age and followed for approximately 3 months. Using cut-points of serum total protein of 5.2 and 5.7 g/dl, the incidences of failure of transfer of passive immunity (FTPI) were 11 and 32%, respectively. A cut-point of 5.7 g/dl was the most predictive of BRD before 5 weeks of age (sensitivity = 40%, specificity = 69%). The positive predictive value was poor (PPV = 18%), but the negative predictive value was good (NPV = 87%). A cut-point of 5.2 g/dl was most predictive of death before 5 weeks of age (sensitivity = 27%, specificity = 89%, PPV = 5%, NPV = 98%). Serum total protein during the first week of life was a poor predictor of NCD. Over 23% of calves were treated for diarrhea. Risk factors were weight at enrollment, other diseases before 2 weeks of age, and an interaction between season of birth and herd-level incidence of NCD. Almost 22% of calves were treated at least once for BRD. Factors associated with an increased risk of BRD included herd-level incidence of BRD, season of birth, navel dipping, other diseases before 2 weeks of age, failure of transfer of passive immunity, and manual control of temperature in pre-weaning housing. Administration of supplemental antibody products at birth was associated with a reduced incidence of BRD. Overall mortality was 3.5%. Risk of mortality was increased by treatment for BRD and other diseases. The mean average weight gain was 0.95 kg/day (range: 0.11–1.62 kg/day; SD = 0.2). Twinning status, FTP, treatment for NCD or other diseases, and month of birth influenced body weight. This study illustrated relationships among various diseases, mortality, and growth. Furthermore, it demonstrated the importance of colostrum for protection against BRD and improved growth performance, while bringing into question the optimal method of determining failure of transfer of passive immunity.     

Selenium content in the hair of newborn dairy heifer calves and its association with preweaning morbidity and mortality.

Hair samples from newborn heifer calves on Holstein dairy farms in southwestern Ontario were analyzed for selenium content by means of instrumental neutron activation analysis. The mean selenium level in the hair of calves which subsequently died at less than six weeks of age did not differ from selenium levels in the hair of calves matched by farm and birthday (overall mean 0.28 ppm). The mean selenium level in the hair of calves which were not treated for disease during the first four weeks of life was 0.42 ppm, while that from appropriately matched treated calves was 0.36 ppm; the difference between the means was significant at p = 0.054. Based on the above associations, it is suggested that higher selenium levels in newborn calves may have some protective effect against morbidity.     

Effect of antibiotic treatment of young calves on glucose absorption and some plasma components

Oral treatment of 10-15 day-old calves with either chloramphenicol (55 mg/kg body wt) or tetracycline (11 mg/kg body wt) did not induce diarrhoea. Treatment caused significant elevation of plasma Na+, K+ and total protein. Calves treated with chloramphenicol showed retarded glucose absorption from the gut.     

Changes in blood and bronchoalveolar lavage fluid components in calves with experimentally induced pneumonic pasteurellosis

Pneumonic pasteurellosis was experimentally induced in calves by inoculation of 5 x 10(8) Pasteurella haemolytica organisms into the right diaphragmatic lung lobe. Blood and bronchoalveolar lavage fluid samples were obtained prior to inoculation and at postinoculation hour (PIH) 2, 4, and 6. Calves developed acute lung injury, characteristic of pneumonic pasteurellosis. Lesions were found only in the right diaphragmatic lobe. By PIH 4, significant (P less than 0.01) increases were detected in lavage fluid total cell count, neutrophil count, total protein and albumin concentrations, and alkaline phosphatase (ALP) and lactic dehydrogenase (LD) activities. Myeloperoxidase and elastase activities did not increase. Neutrophil depletion ameliorated the lung lesions and prevented the increase in lavage fluid cell count, total protein, and albumin concentrations and ALP and LD activities. Treatment with the iron chelator, deferoxamine mesylatehydroxyethyl starch, attenuated the increase in total protein and albumin concentrations and ALP and LD activities at PID 4, but not PIH 6. Treatment with a neutrophil function inhibitor, pentoxifylline, prevented the increase in lavage fluid neutrophil numbers, but accentuated the increase in total protein and albumin concentrations, and ALP, LD, myeloperoxidase, and elastase activities.     

Factors associated with morbidity and mortality in feedlot calves: the Bruce County beef project, year two.

The results of the second year of the project confirmed most of the major findings from the initial year. Feeding cornsilage, particularly as the major roughage in the first month after arrival was associated with excess mortality. Mixing of cattle from different sources and vaccinating against respiratory disease appeared to be the most important additional factors that increased mortality rates. Delaying vaccination at least two days postarrival may have prevented the negative effects of vaccination but only in calves fed cornsilage. Morbidity rates were highly variable among farms but were positively correlated with mortality rates and treatment costs. The occurrence of infectious thromboembolic meningoencephalitis appeared to share some of the same risk factors as mortality; whereas, urolithiasis did not. Water deprivation may be a risk factor in the occurrence of urolithiasis. Fibrinous pneumonia was again the most frequent cause of death. Relative to year one, infectious thromboembolic meningoencephalitis increased in frequency and only one death was attributed to bovine virus diarrhea.     

Relationship between occurrence of white diarrhea and changes of properties and components of blood and milk in their dams after parturition in Japanese Black calves.

We investigated the diet content and properties of blood and milk in 11 pairs of Japanese Black cows and their calves for the one month following delivery. Four pairs (group A) had been no cases of white diarrhea during the year prior to this study, and 7 pairs (group B) had been a high occurrence of white diarrhea in calves during the same period. Properties of dams' diet in groups A and B before the onset of white diarrhea in calves were as follows: TDN fullness rate 98 +/- 2% vs. 110 +/- 5%, DCP fullness rate 151 +/- 2% vs. 200 +/- 33%, and starch content 5 +/- 2% vs. 14 +/- 3%. Blood and milk samples were collected from cows weekly and at the onset of white diarrhea in calves. No calves in group A had white diarrhea, while 5 out of 7 calves in group B had the diarrhea in this study. All cows were fed mixed hay, but 3 out of 5 cows whose calves had white diarrhea had been additionally given 3.0-3.5 kg of corn-silage a day from 4-5 days before onset. In all cows in the white diarrhea development group, the fat content of milk increased by 2.94 +/- 1.82% at the day of onset in comparison before. Serum TG and BUN, respectively, increased by 3.8 +/- 1.3 mg/dl and 3.7 +/- 2.0 mg/dl. Feeding cows a low-starch diet and additional corn-silage may induce a transient increase in blood TG, BUN and milk fat, which may contribute to the occurrence of white diarrhea in calves.     

Genetic relationships between temperament of calves at auction and carcass traits in Japanese Black cattle

Correlations of calves’ temperament with carcass traits were estimated to clarify the genetic relationships between them in Japanese Black cattle. The temperament records for 3128 calves during auction at a calf market were scored on a scale of 1 (calm) to 5 (nervous) as temperament score (TS ), and the TS were divided into two groups (TSG ): TS 1 and 2 comprised TSG 1, and 3 to 5 constituted TSG 2. Carcass data were obtained from 33 552 fattened cattle. A threshold animal model was used for analyzing the underlying liability for TSG , whereas a linear one was used for TS and carcass traits. The heritability estimates for TS and TSG were 0.12 and 0.11, respectively. On the other hand, moderate to high heritability estimates were obtained for carcass traits (0.40 to 0.68). The temperament scores were negatively correlated with carcass weight, rib thickness and subcutaneous fat thickness (?0.13 to ?0.59). In contrast, weak to moderate positive correlations were found between the temperament scores and rib eye area or yield estimate (0.16 to 0.45). The temperament scores and beef marbling score had no correlation. These results showed that it is possible to improve temperament and carcass traits simultaneously.     

Pre-weaning morbidity and mortality of llamas and alpacas

Objectives   To describe the morbidity and mortality patterns and identify factors associated with morbidity in pre-weaning llamas and alpacas.
Design   Cross-sectional observational study of 287 crias born on four farms in Ohio, USA
Procedure   Historical data representing all crias born over a 6-year period were obtained from two llama farms and two alpaca farms in Ohio. Multivariable generalised linear mixed effects regression models were used to identify factors associated with morbidity outcomes.
Results   In total, 105 (37%) of the llamas and alpacas had some reported morbidity during the pre-weaning period, and mortality rate was 2.1%. In addition, 51 (18%) of llamas and alpacas experienced morbidity because of infectious disease, and 47 (16%) experienced morbidity during the neonatal period. The three most commonly reported morbidity events were undifferentiated diarrhoea (23%), umbilical hernia (16%) and unspecified infectious disease (15%). Difficult birth was an important risk factor for pre-weaning morbidity in this population.
Conclusions   Camelid veterinarians and their clients can expect that pre-weaning health events are common among crias, although mortality is low. Crias experiencing difficult births may require additional monitoring for health events during the pre-weaning period.     

Effect of vaccination with the R mutant Escherichia coli (J5) antigen on morbidity and mortality of dairy calves

A prospective cohort study was undertaken to determine the efficacy of Escherichia coli 0111:B4 (J5) vaccination in dairy calves. Calves on 2 units were vaccinated when they were 2 to 3 days old and 2 weeks later with the J5 antigen or they were left unvaccinated, and were observed during the first 60 days of age for morbidity and mortality. Events recorded were death, the first case of illness, the first sign of a respiratory tract condition, the first sign of diarrhea, and the first treatment. The time to death or to a morbid event was examined as a function of vaccination status, using the Cox model of survival analysis, where serum IgG concentration at 2 to 3 days of age and gender of the calf were included to control confounding. Signs of morbidity in 517 calves were followed, 189 from unit 1 and 328 from unit 2. Vaccination was associated with a 2.15-fold reduction in risk of death on unit 2 (P = 0.042), but with a 2.43-fold increase in risk of death on unit 1 (P = 0.0035). The only association found between vaccination and morbidity was a 1.34-fold reduction in risk of respiratory tract signs for vaccinated calves on unit 2 (P = 0.055). Necropsy results and clinical investigations indicated that calves on unit 1 were poorly nourished and emaciated. Antibodies to J5 2 weeks after vaccination were significantly (P = 0.0002) lower in calves on unit 1 than in calves on unit 2. The findings offered a possible explanation for the adverse vaccination effect in calves on unit 1.(ABSTRACT TRUNCATED AT 250 WORDS)