Clinical trial on type of calving pen and the risk of disease in Holstein calves during the first 90 d of life

Herd-level risk factors associated with preweaning mortality on Ontario dairy farms

The objective of this cross-sectional, herd-level study was to identify associations between calf management practices and herd-level preweaning mortality on Ontario dairy farms. From April to August 2022, a convenience sample of 100 dairy farms from Ontario, Canada, were visited once. A questionnaire, covering farm biosecurity, calving, colostrum management, preweaning nutrition, and housing, was verbally administered at each farm visit. Furthermore, data regarding preweaning calf mortality were retrieved from each farm's herd management software or records, including the total count of calves that survived, were culled, or died during the preweaning period for the 365 d before the farm visit. Preweaning mortality was defined as the proportion of calves that died between ≥48 h and 60 d of age divided by the total number of calves alive after 48 h of age. The herd-level preweaning mortality risk on sampled farms ranged from 0 to 15.9%, with an average of 2.8% (SD = 3.8%). A multivariable Poisson regression model was used to evaluate associations between 22 explanatory variables and preweaning mortality. Factors associated with greater herd-level preweaning mortality were larger herd size; having treatment protocols for diarrhea, pneumonia or navel infection written in collaboration with a veterinarian (compared with farms with the same treatment protocols developed without a veterinarian), and the herd-veterinarian never inquiring about calf health (compared with farms where the herd veterinarian inquired sometimes). Factors associated with lower herd-level preweaning mortality were using the calving pen for sick cows, having more than 4 people working with calves, offering calves a minimum volume of ≥9 L of milk/day, and farmers with a level of formal education higher than secondary school. These results indicate that producers may be able to reduce preweaning calf mortality by providing adequate labor for calf care, offering calves sufficient volumes of milk, being proactive in communicating with their veterinary practitioners about calf health, and potentially by engaging in continuous education.

INVITED REVIEW: An evaluation of EFSA opinion on calf welfare from a nutritional and management perspective

In March, 2023, the European Food Safety Authority published a Scientific Opinion on Calf Welfare. This Opinion was prepared in response to a request from the European Commission to provide an independent view on the welfare of calves that reflected the most recent scientific knowledge. Data sources used to develop their recommendations included peer-reviewed studies, expert knowledge, and gray literature. The Opinion considered specific scenarios and welfare consequences of specific management practices, including feeding fiber to calves raised for white veal and amount of cow-calf contact. Their Opinion suggested that calves should be fed specific quantities of forage NDF during the rearing cycle. Regarding separation of calves, the Committee recommended that the calf should remain with the cow for a minimum of 24 h and then be housed with another calf. They further suggested that prolonged cow-calf contact should increasingly be implemented due to benefits to both cow and calf to minimize stress of separation. The objective of this review is to assess the veracity of these recommendations and the scientific data that underpins them. This review will present a literature to support the contention that, from a nutritional and management perspective, these recommendations may impair calf welfare by exposing calves to innutritious rations containing excess fiber and increasing their risk of morbidity and mortality due to poor colostrum intake and exposure to disease-causing pathogens. Alternative recommendations are made that may further the goal of calf welfare in the context of nutrition and housing.

Welfare of calves

This Scientific Opinion addresses a European Commission request on the welfare of calves as part of the Farm to Fork strategy. EFSA was asked to provide a description of common husbandry systems and related welfare consequences, as well as measures to prevent or mitigate the hazards leading to them. In addition, recommendations on three specific issues were requested: welfare of calves reared for white veal (space, group housing, requirements of iron and fibre); risk of limited cow–calf contact; and animal‐based measures (ABMs) to monitor on‐farm welfare in slaughterhouses. The methodology developed by EFSA to address similar requests was followed. Fifteen highly relevant welfare consequences were identified, with respiratory disorders, inability to perform exploratory or foraging behaviour, gastroenteric disorders and group stress being the most frequent across husbandry systems. Recommendations to improve the welfare of calves include increasing space allowance, keeping calves in stable groups from an early age, ensuring good colostrum management and increasing the amounts of milk fed to dairy calves. In addition, calves should be provided with deformable lying surfaces, water via an open surface and long‐cut roughage in racks. Regarding specific recommendations for veal systems, calves should be kept in small groups (2–7 animals) within the first week of life, provided with ~ 20 m²/calf and fed on average 1 kg neutral detergent fibre (NDF) per day, preferably using long‐cut hay. Recommendations on cow–calf contact include keeping the calf with the dam for a minimum of 1 day post‐partum. Longer contact should progressively be implemented, but research is needed to guide this implementation in practice. The ABMs body condition, carcass condemnations, abomasal lesions, lung lesions, carcass colour and bursa swelling may be collected in slaughterhouses to monitor on‐farm welfare but should be complemented with behavioural ABMs collected on farm.

A High Plane of Nutrition Is Associated with a Lower Risk for Neonatal Calf Diarrhea on Bavarian Dairy Farms

Simple Summary

Calf mortality and morbidity are still unacceptably high on many dairy farms worldwide. Neonatal calf diarrhea is the most common cause of disease and death in young calves. This study attempted to identify risk factors that are associated with the outbreak of this multifactorial disease on Bavarian dairy farms. For this purpose, farms with calf diarrhea as a herd problem were compared to farms without veterinarian treatment for calf diarrhea for one year before the study visit. The main factor that was associated with a lower risk of neonatal diarrhea was the provision of adequate amounts of milk as compared with lower milk feeding levels. In contrast, supplementation with iron soon after birth was associated with a higher risk for calf diarrhea as a herd problem. It is well known that poor colostrum management and restricted milk feeding compromise calf development and weaken the immune system. Therefore, it is not surprising that calves receiving more colostrum and more milk have a higher chance of remaining healthy. Ad libitum feeding of calves in the first three weeks of life is recommended. The observed association between an increased calf diarrhea risk and supplementation with iron after birth requires further investigation.

Abstract

In all bovine production systems, neonatal calf diarrhea remains worldwide an important issue of economic losses and animal welfare. The aim of the present study was to identify risk factors for neonatal calf diarrhea as a herd health problem on Bavarian dairy farms. For the purpose of this study, management factors related to calf health were retrospectively compared between 59 dairy farms with calf diarrhea as a herd problem with those of 18 control farms, where no veterinary treatment of calves for neonatal calf diarrhea took place for at least one year prior to the farm visit. A multivariable binary logistic regression analysis of management factors indicated that administration of 3 L or more of colostrum at the second feeding after birth (Odds ration [OR] = 0.21, 95% confidence interval [95% CI] = 0.05–0.89), ad libitum feeding of milk during the first week of life (OR = 0.06, 95% CI = 0.006–0.60), and administration of an iron containing preparation after birth (OR = 10.9, 95% CI = 1.25–95.6) were independently associated with the presence of a herd problem with neonatal diarrhea. Results of this study therefore suggest that a higher plane of nutrition is a protective factor with regard to the occurrence of neonatal diarrhea on Bavarian dairy farms. These findings support the establishment of ad libitum feeding programs in dairy calf rearing.

Calving Management: A Questionnaire Survey of Veterinary Subject Matter Experts and Non-Experts

Simple Summary

We designed a questionnaire and asked two groups of veterinarians: (1) subject matter experts, who had published on calving management and (2) veterinary practitioners) for their opinion about aspects of calving management. Participants recommended to differentiate between the two stages of parturition and emphasized signs of imminent parturition, such as “restlessness” and “visibility of fetal parts”. There was no consensus on the right time to move the cow to the maternity pen. Almost half of the respondents recommended a 6-h observation interval for prepartum cows in the maternity pen. The two veterinary groups differed little in their knowledge of calving management.

Abstract

Accurate detection of the onset of parturition is a key factor in the prevention of dystocia. In order to establish current best practice recommendations for calving management, we asked subject matter experts (SME) who had published on calving management (by online survey, n = 80) and non-SMEs, veterinary practitioners (by workshop survey, n = 24) for their opinions. For this, we designed a questionnaire on the significance of signs of imminent parturition (SIP), the frequency of calving observation, and influencing factors for the timing of cow movement to a maternity pen. The response rate was 67.5% in the online survey and 100% in the workshop survey. The majority (89.7%) of all respondents agreed that it is beneficial for successful calving management to differentiate between stage I and II of parturition. Of 12 signs of imminent parturition (for stage I and II), “restlessness” and “visibility of fetal parts in vulva” were cited by 56.5% and 73.3% of SME and non-SME respondents, respectively. There was no consensus on the right time to move the cow to the maternity pen; recommendations varied from one to over 21 days. Almost half of the respondents (45.7%) recommended a 6-h observation interval for prepartum cows in the maternity pen. This study identified a strong consensus on the SIP and how and when to observe cows prior to parturition. SMEs and non-SMEs provided broadly similar recommendations, while the SMEs and the non-SMEs differed significantly in the number of publications on calving they authored, they differed little in their knowledge of calving management.

Rotavirus in Calves and Its Zoonotic Importance

Rotavirus is a major pathogen responsible for diarrheal disease in calves, resulting in loss of productivity and economy of farmers. However, various facets of diarrheal disease caused by rotavirus in calves in the world are inadequately understood, considering that diarrheal disease caused by rotavirus is a vital health problem in calves that interrupts production benefits with reduced weight gain and increased mortality, and its potential for zoonotic spread. The pathological changes made by rotavirus are almost exclusively limited to the small intestine that leads to diarrhea. It is environmentally distributed worldwide and was extensively studied. Reassortment is one of the important mechanisms for generating genetic diversity of rotaviruses and eventually for viral evolution. So, the primary strategy is to reduce the burden of rotavirus infections by practicing early colostrum's feeding in newborn calves, using vaccine, and improving livestock management. Rotaviruses have a wide host range, infecting many animal species as well as humans. As it was found that certain animal rotavirus strains had antigenic similarities to some human strains, this may be an indication for an animal to play a role as a source of rotavirus infection in humans. Groups A to C have been shown to infect both humans and animals. The most commonly detected strains in both human and animals are G2, G3, G4, and G9, P [6]. Therefore, this review was made to get overview epidemiology status and zoonotic importance of bovine rotavirus.

Implementation of management recommendations in unweaned dairy calves in western Germany and associated challenges

To improve the welfare of livestock, it is important to assess management practices on farms and to identify areas where current scientific recommendations are rarely implemented. Differences in the implementation of recommendations might be explained by the individual farm as well as the characteristics of survey respondents and their attitude toward animal welfare. Hence, the aim of this study was to assess dairy calf management practices, compare them with current scientific recommendations, and to explore factors that influence implementation of the recommended management practices. A 1.5-h interview was performed with stockpersons on 42 dairy farms (mean herd size ± SD = 149.9 ± 16.6 cows) distributed across western Germany in 2018 to 2019. We observed that the management of unweaned calves varied greatly from farm to farm in aspects such as milk-feeding protocols; timing of grouping and disbudding; and access to water, roughage, and concentrate. Major deviations from management recommendations were (1) cleaning calving pen only by removal of bedding without a following disinfection before restocking on 23.8% farms, cleaning of teat buckets without detergents and disinfection (23.8 and 11.9% of farms, respectively), and failure to disinfect navels (29.3% of farms); (2) separating calf and dam after only 5 to 8 h postpartum for calving at night in 97.6% farms and unchecked colostrum quality by 23.8% of survey respondents; (3) feeding waste milk by 72.4% of the farms surveyed; and (4) removing supernumerary teats and disbudding without local anesthesia (90 and 80% farms surveyed, respectively). The number of implemented recommendations on the farms surveyed correlated with who was responsible for calf rearing, and whether prioritizing animal welfare was considered important by the respondents. This study indicated that limitations of individual housing systems, time management, the stockperson's knowledge, and the stockperson's ability to relate to animals posed challenges in implementation of the recommendations. Further research on challenges in calf management and how to overcome them would be helpful to improve calves' welfare in current husbandry systems.

Epidemiology of bovine respiratory disease (BRD) in preweaned calves on California dairies: The BRD 10K study

Bovine respiratory disease (BRD) is one of the leading causes of death in dairy heifers. The objective of this prospective cohort study was to characterize the epidemiology of BRD in preweaned dairy calves and to identify management practices associated with decreased risk of BRD. Dairies were chosen for the study based on management practices, location, size, and willingness to participate. A total of 6 dairies, ranging in size from 700 to 3,200 milking cows, in 6 counties across California's Central Valley, were enrolled in the study for at least 1 year. A total of 11,945 calves were born on the study dairies and followed until weaning. Incidence of BRD was estimated using treatment records. Trained study personnel performed comprehensive calf management surveys and estimated BRD prevalence on every dairy at least once every season. A shared frailty model was used to model the associations between management practices and BRD hazard. The final models included data from complete records of 11,470 calves. The overall BRD study period prevalence across the study herds was 22.8%. The mean BRD incidence density rate on all the study dairies was 0.17 BRD cases [95% confidence interval (CI) = 0.16-1.74] per calf-month at risk. The shared frailty model identified that feeding only waste or saleable milk (compared with use of milk replacer), feeding over 3.8 L of milk per day to calves under 21 d of age, frequent changing of maternity pen bedding, and administration of modified live or killed BRD vaccines to dams before calving significantly reduced the risk of BRD. Risk factors for BRD included housing calves in wooden hutches with metal roofs, compared with all-wood hutches, twin births, and perception of dust occurring "regularly," as reported by calf managers, compared with a perception of "no dust" in the calf-raising area. All 4 seasons were analyzed, and both summer (hazard ratio = 1.15; 95% CI = 1.01 to 1.32) and spring (hazard ratio = 1.26; 95% CI = 1.11 to 1.44) were associated with a higher risk of BRD compared with winter. The current longitudinal study identified specific housing and feeding practices that could be modified to decrease risk of BRD. In addition, season was observed to have a strong effect on calves' risk of developing BRD on California dairies.

Regional management practices and prevalence of bovine respiratory disease in California's preweaned dairy calves

The objective of this cross-sectional study was to estimate the prevalence of bovine respiratory disease (BRD) in California preweaned dairy calves and identify management practices that are associated with BRD. A convenience sample of 100 dairies in the 3 distinct dairy regions of California was surveyed. Regions evaluated were Northern California (NCA), northern San Joaquin Valley (NSJV), and greater Southern California (GSCA). A questionnaire on calf management practices and demographic information was administered via in-person interviews at each dairy and a random sample of preweaned calves was evaluated using the California BRD scoring system on the same day. Prevalence of BRD varied between the 3 dairy regions: 9.30% in NCA, 4.51% in NSJV, and 7.35% in GSCA. Breed was not associated with BRD prevalence at the statewide level, but differences in prevalence were observed between breeds across the regions with a higher prevalence in NCA for Jerseys and in GSCA for Holsteins, compared with NSJV. Prevalence of BRD was not different between organic and conventional dairies. Colostrum management practices, including heat treatment and feeding colostrum from multiparous cows, varied by region and were associated with lower BRD prevalence. Calves housed in group pens, a practice observed primarily in NCA, had a higher BRD prevalence than those in individual housing. Feeding salable milk was also more common in NCA and was associated with lower BRD prevalence. Ground and road surfaces adjacent to the calf raising area were also variable by region, and paved surfaces were associated with lower BRD prevalence. Management practices associated with BRD varied across the state and may be addressed to inform the adoption and implementation of potentially protective management decisions on California dairies and other regions with similar dairy systems.

Relationship between selected perinatal paratuberculosis management interventions and passive transfer of immunity in dairy calves

The objective of this cohort study was to assess the relationship between perinatal calf management practices relevant to the control of paratuberculosis and passive transfer of immunoglobulin in calves born in an endemically infected Irish dairy herd. Data from 176 calves were used to assess the effect of time spent in the calving area, individual versus non-designated calving and colostrum pasteurisation on serum total protein, zinc sulphate turbidity, globulin and γ-glutamyltransferase. In addition, the effects of colostrum quality, volume of colostrum fed, method of colostrum administration and calving season on passive transfer were quantified. Serum samples were collected as part of routine herd health monitoring from calves aged between one and seven days. Multivariate linear and logistic regression models were used to assess the effect of each variable on the test result and failure of passive transfer as determined using a cut-off point for each diagnostic test. Colostrum pasteurisation and calving area were not significantly associated with passive transfer, whereas increased time spent in the calving pen was consistently associated with a detrimental effect. In addition, a strong seasonal effect was apparent, which appeared to be unrelated to colostrum quality and calf management. The authors are unaware of published studies documenting such a significant seasonal effect on passive transfer.

Survey of management practices related to bovine respiratory disease in preweaned calves on California dairies

In the spring of 2013, a survey of California (CA) dairies was performed to characterize management practices related to bovine respiratory disease in preweaned calves, compare these practices across geographic regions of the state, and determine the principal components that explain the variability in management between herds. The questionnaire consisted of 53 questions divided into 6 sections to assess management practices affecting dairy calves from precalving to weaning. The questionnaire was mailed to 1,523 grade A licensed dairies in CA and 224 responses (14.7%) were collected. Survey response rates were similar over the 3 defined regions of CA: northern CA, northern San Joaquin Valley, and the greater southern CA region. The mean size of respondent herds was 1,423 milking cows. Most dairies reported raising preweaned calves on-site (59.7%). In 93.3% of dairies, preweaned calves were raised in some form of individual housing. Nonsaleable milk was the most frequent liquid diet fed to preweaned heifers (75.2%). Several important differences were identified between calf-raising practices in CA and practices reported in recent nationwide studies, including herd sizes, housing practices, and sources of milk fed to heifers. The differences between the CA and nationwide studies may be explained by differences in herd size. Regional differences within CA were also identified. Compared with the 2 other regions, northern CA dairies were found to have smaller herds, less Holstein cattle, calves remained with dams for longer periods of time after calving, were more likely to be certified organic dairies, and raised their own calves more often. Principal component analysis was performed and identified 11 components composed of 28 variables (questions) that explained 66.5% of the variability in the data. The identified components and questions will contribute to developing a risk assessment tool for bovine respiratory disease in preweaned dairy calves.

Farm characteristics and calf management practices on dairy farms with and without diarrhea: a case-control study to investigate risk factors for calf diarrhea

Calf diarrhea is one of the most important problems in calf rearing on dairy farms worldwide. Besides pathogens, several noninfectious management factors, especially management around birth, colostrum management, calf housing, feeding, and hygiene are important in the pathogenesis of diarrhea. To date, few data are available concerning calf rearing management on small and medium-sized dairy farms that are typical for Austria and the alpine region. Consequently, the objectives of this case-control study were to evaluate routine calf management practices on Austrian dairy farms and to examine differences in management between farms with and without the presence of calf diarrhea to identify risk factors. Overall, 100 dairy farms were visited. Of these farms, 50 were chosen based on the history and presence of calf diarrhea (case farms). Another 50 farms with no presence of calf diarrhea were chosen to serve as a standard of comparison (control farms). On farms, management was evaluated by face-to-face interview, and health status and hygiene were surveyed. Several calf rearing management procedures were similar on all of the visited farms, especially in areas regulated by national and European law. These factors include colostrum management and feeding. Consequently, no influence of these factors on the appearance of calf diarrhea could be detected. In contrast, other areas such as hygiene measures differed between farms and showed a partial association with the presence of calf diarrhea on farm. Variables related to diarrhea on farm were farm size; that is, the number of cows on farm. Farms with diarrhea cases were larger (median 40 cows, interquartile range 24.5 to 64.0) compared with farms with no presence of diarrhea (median 28 cows, interquartile range 18.8 to 44.0). Other risk factors that influenced the presence of diarrhea were the presence of other farm animal species on the farm [odds ratio (OR) 26.89, 95% confidence interval (CI): 2.64 to 273.5], frequency of cleaning of the calving area (OR 0.12, 95% CI: 0.02 to 0.79), the placement of individual calf housings (barn vs. outdoors; OR 0.02, 95% CI: 0.00 to 0.47), and the presence of respiratory tract disease (OR 52.49, 95% CI: 1.26 to 2,181.83). The possible influence of these factors on the appearance of calf diarrhea should be considered when farmers are advised.

Economic evaluation of participation in a voluntary Johne's disease prevention and control program from a farmer's perspective--The Alberta Johne's Disease Initiative

The Alberta Johne's Disease Initiative (AJDI) is a Johne's disease (JD) control program with the goal of reducing the spread of Mycobacterium avium ssp. paratuberculosis (MAP) through implementation of best management practices. The objective was to estimate the economic benefit of participation in the AJDI. A decision tree was constructed in which disease prevalence, test characteristics, and probabilities for implementation of best management practices suggested by herd veterinarians were implemented. Analysis was performed using a Markov analysis, and input data were assigned using estimates from the AJDI and published data. A cost-effectiveness analysis was performed and the net benefit of participation (from the perspective of a dairy farmer) in the AJDI compared with no participation was calculated. A series of 1-way sensitivity analyses were used to control for uncertainty. Farms participating in the AJDI were estimated to have a net benefit of Can$74 per cow over the course of 10 yr. If project costs were covered by the participating farm, the net benefit was Can$27. In addition to the effects on MAP infection, a reduction in calf diarrhea was modeled for farms that improved their calf management through the use of pasteurizers. In that case, the additional costs outweighed additional revenues compared with the baseline analysis, resulting in a reduced net benefit of Can$19. Participation would not be cost effective if cows in early stages of MAP infection did not have decreased production and if prevalence of MAP infection did not increase on farms with poor management. A limitation of the study, despite high uncertainty in some input parameters, was the lack of knowledge regarding changes in prevalence on farms with various management strategies. In conclusion, participation in the AJDI was cost effective for the average Alberta dairy farm.

Herd health status and management practices on 16 Irish suckler beef farms

Background

There have been few studies published internationally which document herd health management practices in suckler beef herds and no published Irish studies. The study objective was to document herd health status and management practices on sixteen Irish suckler beef herds over a two year period (2009–2010). The farms used in the study were part of the Teagasc BETTER farm beef programme. The mean (s.d.) herd size, stocking rate and farm size was 68 cows (27.6), 2.0 LU/ha (0.3) and 64.3 (21.6) adjusted hectares, respectively. Two questionnaires were designed; 1) a farmer questionnaire to collect information on farm background and current herd health control practices and 2) a veterinary questionnaire to collect information on the extent of animal health advice given by veterinarians to their clients and identification of any on-farm herd health issues.

Results

Dystocia, calf pneumonia, and calf diarrhoea, in that order, were identified as the primary herd health issues in these Irish suckler beef herds. In addition, substantial deficiencies in biosecurity practices were also identified on these farms.

Conclusions

The findings of this study may serve as the focus for future research in animal health management practices in Irish suckler beef herds.

A randomized controlled trial on preweaning morbidity, growth and mortality in Holstein heifers fed a lacteal-derived colostrum replacer or pooled maternal colostrum

BACKGROUND

The objective of this randomized controlled trial was to determine the effect of feeding a commercial lacteal-derived colostrum replacer (CR) or pooled maternal colostrum (MC) on preweaning morbidity, growth and mortality in Holstein heifer calves. A total of 568 calves were randomly assigned to be fed either 3.8 L of pooled MC or two doses (200 g IgG) of a CR. Calves were monitored daily for preweaning morbidity until weaning at 60 d old. Birth and weaning weights were measured to estimate growth rates.

RESULTS

Calves fed CR were significantly less likely to be affected with a diarrhea event (OR = 0.58; 95% CI, 0.38 to 0.88; P value = 0.011) and had a higher rate of daily weight gain (0.051 kg/day; 95% CI, 0.03 to 0.08; P value <0.001) compared to calves fed pooled MC. Use of lacteal-derived colostrum replacer was not significantly associated with respiratory disease (OR = 1.01; 95% CI 0.67 to 1.51; P value = 0.974 ), omphalitis (OR = 0.93; 95% CI 0.06 to 14.86; P value = 0.956), or mortality (HR = 0.71; 95% CI 0.27 to 1.92; P value = 0.505) in the study calves.

CONCLUSIONS

The lacteal-derived CR fed at the study dose was a viable colostrum alternative in the event of poor quality pooled MC for the prevention of preweaning diarrhea and resulted in higher growth rates in comparison to calves fed pooled MC in the study herd.

Scientific Opinion on the welfare of cattle kept for beef production and the welfare in intensive calf farming systems

Information given in previous Opinions "Welfare of cattle kept for beef production" (SCAHAW, 2001) and "The risks of poor welfare in intensive calf farming systems" (EFSA, 2006) is updated and recent scientific evidence on the topics reviewed. Risks of poor welfare are identified using a structured analysis, and issues not identified in the SCAHAW (2001) beef Opinion, especially effects of housing and management on enteric and respiratory diseases are reviewed. The Opinion covers all systems of beef production, although the welfare of suckler cows or breeding bulls is not considered. The Chapter on beef cattle presents new evidence and recommendations in relation to heat and cold stress, mutilations and pain management, digestive disorders linked to high concentrate feeds and respiratory disorders linked to overstocking, inadequate ventilation, mixing of animals and failure of early diagnosis and treatment. Major welfare problems in cattle kept for beef production, as identified by risk assessment, were respiratory diseases linked to overstocking, inadequate ventilation, mixing of animals and failure of early diagnosis and treatment, digestive disorders linked to intensive concentrate feeding, lack of physically effective fibre in the diet, and behavioural disorders linked to inadequate floor space, and co-mingling in the feedlot. Major hazards for white veal calves were considered to be iron-deficiency anaemia, a direct consequence of dietary iron restriction, enteric diseases linked to high intakes of liquid feed and inadequate intake of physically effective fibre, discomfort and behavioural disorders linked to inadequate floors and floor space.

Distribution of immune cells and expression of interleukin receptors in ileal Peyer's patches of calves

Newborn calves lack a mature immune system. The immune system develops with age, but the role of the expression of cytokine receptors in the development of immune cells of Peyer's patches (PPs) in the intestines of calves in the first 2 months has not yet been elucidated. In this study, the distribution of immune cells and the expression of interleukin (IL) receptors (R) in the ileal PPs of newborn and 2-month-old calves were investigated immunohistochemically with monoclonal antibodies against bovine CD4, CD8, IgM, γδTCR, T19, WC3, WC5, and WC6 antigens. The expression of ILRs was examined with antibodies against CD25 (IL-2Rα), IL-2Rγ, IL-4R, IL-6R, IL-10R, and IL-13R antigens. CD4(+), CD8(+), γδTCR(+), T19(+), and WC6(+) cells were found to be more widely distributed in the ileal PPs of 2-month-old calves than in those of newborn calves. Moreover, the expression of CD25 (IL-2Rα), IL-4R, and IL-13R in the ileal PPs of 2-month-old calves was more prominent than that in newborn calves. These data suggest that the immune system of calves at 2 months of age is developed by reactions to foreign antigens and aging.

Calf health from birth to weaning. I. General aspects of disease prevention

Calfhood diseases have a major impact on the economic viability of cattle operations. This is the first in a three part review series on calf health from birth to weaning, focusing on preventive measures. The review considers both pre- and periparturient management factors influencing calf health, colostrum management in beef and dairy calves and further nutrition and weaning in dairy calves.

The REFLECT statement: reporting guidelines for randomized controlled trials in livestock and food safety: explanation and elaboration

Concerns about the completeness and accuracy of reporting of randomized clinical trials (RCTs) and the impact of poor reporting on decision-making have been documented in the medical field over the past several decades. Experience from RCTs in human medicine would suggest that failure to report critical trial features can be associated with biased estimated effect measures, and there is evidence to suggest similar biases occur in RCTs conducted in livestock populations. In response to these concerns, standardized guidelines for reporting RCTs were developed and implemented in human medicine. The Consolidated Standards of Reporting Trials (CONSORT) statement was first published in 1996 with a revised edition published in 2001. The CONSORT statement consists of a 22-item checklist for reporting a RCT and a flow diagram to follow the number of participants at each stage of a trial. An explanation and elaboration document not only defines and discusses the importance of each of the items, but also provides examples of how this information could be supplied in a publication. Differences between human and livestock populations necessitate modifications to the CONSORT statement to maximize its usefulness for RCTs involving livestock. These have been addressed in an extension of the CONSORT statement titled the REFLECT statement: Methods and processes of creating reporting guidelines for randomized control trials for livestock and food safety. The modifications made for livestock trials specifically addressed the common use of group housing and group allocation to intervention in livestock studies, the use of a deliberate challenge model in some trials, and common use of non-clinical outcomes, such as contamination with a foodborne pathogen. In addition, the REFLECT statement for RCTs in livestock populations proposed specific terms or further clarified terms as they pertained to livestock studies.