Calf management practices and associations with herd-level morbidity and mortality on beef cow-calf operations

Survey on colostrum management by German dairy farmers focusing on frozen colostrum storage

Because calves are born with low levels of antibodies, effective colostrum management is one of the most critical factors for successful calf rearing. A timely and adequate supply of sufficiently high-quality colostrum immediately after birth is essential to ensure the passive immunization of calves. Frozen colostrum reserves are recommended to fulfill the immunological and nutrient requirements of newborn calves, even in exceptional situations; however, the implementation rates on German dairy farms and challenges of realization remain unclear. A 33-question online survey, focused on frozen colostrum reserves, was developed to obtain an overview of colostrum management practices on German dairy farms. The questionnaire was divided into 3 sections: 1. personal data; 2. farm characteristics; 3. colostrum management. Of the 155 responses we received, 63.9% were from female farmers, and 35.5% were from male farmers. Conventional farming was practiced on 89.0% of farms, and organic farming was practiced on 7.1% of farms. Of the respondents, 89.0% froze colostrum. The main reasons for freezing colostrum were: 1. the dam does not produce enough colostrum; 2. the dam cannot be milked; or 3. in cases where the dam dies during birth. Farmers primarily froze colostrum from cows during their third to fifth lactation. Before freezing, 33.1% of the respondents measured indicators in the colostrum to estimate Ig concentrations, whereas 2.3% determined the colostrum quality after freezing. Reusable and disposable PET deposits (23.1%, 22.3%) and ColostroBags (20.0%) were the primary containers used to freeze colostrum. The main reasons for not freezing colostrum were the high labor intensity and the availability of fresh colostrum from other cows. Thawing methods included buckets (47.7%) and professional water baths (13.8%). The survey identified areas in which improved knowledge transfer could enhance colostrum management. Furthermore, there appeared to be a lack of specific, feasible instructions for employees concerning the practical implementation of colostrum management. Most importantly, the regular determination and documentation of Ig concentrations should be emphasized. The added value of stored colostrum, relative to a greater workload, should also be promoted, particularly on smaller farms.

Colostrum Replacement and Serum IgG Concentrations in Beef Calves Delivered by Elective Cesarean Section

Assistance during calving and cesarean section (C-section) are important risk factors for the failure of transfer of passive immunity (FTPI) in beef calves, which increases the risk of morbidity and mortality in beef calves during the preweaning period. Colostrum replacement recommendations for beef calves, and especially for those delivered by C-section, are unavailable. The objective of this study was to determine whether or not colostrum replacement or supplementation with a commercially available product could increase serum IgG concentrations in beef calves delivered by elective C-section, compared to beef calves that nursed colostrum naturally. An elective C-section was performed in 32 pregnant beef cows and first-calf heifers. Immediately after delivery, newborn calves were randomly assigned to one of three different treatment groups. Group A calves (n = 7) were fed one packet of a commercial colostrum replacer (CR) product providing 60 g of IgG within 30 min of life. A second packet of the same CR was fed at 6 h of life. Group B calves (n = 13) were fed the same CR at the same frequency as group A; however, these calves were reunited with their dams after the second CR feeding to allow additional nursing of maternal colostrum. Group C calves (n = 12) were united with their dams immediately after surgery without colostrum intervention. Serum IgG levels at 48 h of life were greater in group C calves and in calves born to multiparous cows. Based on the results of this study, neither colostrum replacement nor supplementation result in higher serum IgG concentrations in beef calves delivered by elective C-section compared with natural nursing.

Effect of castration timing and weaning strategy on the taxonomic and functional profile of ruminal bacteria and archaea of beef calves

BACKGROUND

Beef cattle experience several management challenges across their lifecycle. Castration and weaning, two major interventions in the early life of beef cattle, can have a substantial impact on animal performance. Despite the key role of the rumen microbiome on productive traits of beef cattle, the effect of castration timing and weaning strategy on this microbial community has not been formally described. We assessed the effect of four castration time windows (at birth, turnout, pre-weaning and weaning) and two weaning strategies (fence-line and truck transportation) on the rumen microbiome in a randomized controlled study with 32 male calves across 3 collection days (i.e., time points). Ruminal fluid samples were submitted to shotgun metagenomic sequencing and changes in the taxonomic (microbiota) and functional profile (metagenome) of the rumen microbiome were described.

RESULTS

Using a comprehensive yet stringent taxonomic classification approach, we identified 10,238 unique taxa classified under 40 bacterial and 7 archaeal phyla across all samples. Castration timing had a limited long-term impact on the rumen microbiota and was not associated with changes in alpha and beta diversity. The interaction of collection day and weaning strategy was associated with changes in the rumen microbiota, which experienced a significant decrease in alpha diversity and shifts in beta diversity within 48 h post-weaning, especially in calves abruptly weaned by truck transportation. Calves weaned using a fence-line weaning strategy had lower relative abundance of Bacteroides, Lachnospira, Fibrobacter and Ruminococcus genera compared to calves weaned by truck transportation. Some genes involved in the hydrogenotrophic methanogenesis pathway (fwdB and fwdF) had higher relative abundance in fence-line-weaned calves post-weaning. The antimicrobial resistance gene tetW consistently represented more than 50% of the resistome across time, weaning and castration groups, without significant changes in relative abundance.

CONCLUSIONS

Within the context of this study, castration timing had limited long-term effects on the rumen microbiota, while weaning strategy had short-term effects on the rumen microbiota and methane-associated metagenome, but not on the rumen resistome.

Hygiene management practices and adenosine triphosphate luminometry of feeding equipment in preweaning calves on dairy farms in Quebec, Canada

The objective of this study was to describe the cleaning practices currently used for preweaning calves on dairy farms in Quebec, Canada. In addition, contamination of feeding equipment for preweaning calves was described using ATP (expressed as relative light units, RLU), visual assessment, and bacteriological analysis. A questionnaire was administered on 50 commercial dairy farms in Quebec, Canada, regarding the self-reported cleaning protocol used for feeding equipment of preweaning calves. During the visit, a visual score was given to the feeding equipment available at the farm. Afterward, ATP luminometry measurements were obtained using Hygiene UltraSnap and MicroSnap swabs (Hygiene, Camarillo, CA), and the liquid rinsing technique for buckets, nipples, bottles, esophageal tube feeders (ET), the tube of automatic milk feeders (AMF), water samples, and milk replacer. An additional direct swabbing technique was performed on buckets and nipples. The fluid retrieved from the liquid rinsing technique was also used to determine the total bacterial count (TBC) and total coliform count. Based on the bacteriological analysis, optimal RLU cutoff values to determine contamination were obtained. The median (interquartile range) luminometer measurements using the UltraSnap and direct technique for buckets and nipples were 2,082 (348-7,410) and 3,462 (462-7,518) RLU, respectively; and, using the liquid technique for bottles, ET, AMF, water, and milk replacer were 43 (4-974), 15 (4-121), 301 (137-1,323), 190 (71-358), and 94 (38-218) RLU, respectively. Overall, for all equipment and both techniques used, higher RLU values were seen in UltraSnap samples compared with MicroSnap samples. Additionally, for buckets and nipples, higher RLU values were obtained for the direct swabbing method compared with the liquid sampling method for both swabs used. No differences in the level of contamination were seen between the different feeding equipment used within a farm. Overall, a higher correlation with bacteriological results was noticed for ATP luminometry compared with the visual score, with a high correlation for nipples and bottles using the UltraSnap and liquid technique. Based on the classification of "contaminated" (TBC ≥100,000 cfu/mL) or "not contaminated" (TBC <100,000 cfu/mL), optimal ATP luminometer cutoff values for buckets, nipples, bottles, AMF, water, and milk replacer were 798, 388, 469, 282, 1,432, and 93 RLU, respectively. No clear association was found between ATP measurements and the self-reported cleaning protocol. This study gave new insights into the current cleaning procedures and contamination of feeding equipment for preweaning calves on dairy farms in Quebec. In addition, ATP luminometry cutoff values could help benchmark farms regarding cleaning practices and provide customized advice, improving the overall hygiene management, and thus the health, of preweaning calves on dairy farms.

Risk factors associated with calf mortality in Western Canadian cow-calf operations

This study examined the influence of management practices and herd demographics on calf mortality proportions in Western Canadian cow-calf operations, utilizing data from the second Western Canadian Cow-calf Survey. The survey was conducted between October 23, 2017, and February 28, 2018. The survey, which was open to all cow-calf producers across Western Canada, provided producer-reported data regarding calf death loss and corresponding herd-level factors. A fractional logit model was employed to identify significant factors associated with calf mortality proportions. The findings revealed that shorter breeding seasons (<63 days), calves born within the same season, and regular pregnancy checks for breeding females were negatively associated with calf mortality proportions. Conversely, regular breeding soundness evaluations for breeding bulls, traditional weaning methods, and vaccinating heifers for scours showed positive associations with increased calf mortality proportions. Herd operations where dams were vaccinated against clostridial and bovine respiratory diseases had lower calf mortality proportions. Notably, operations with experienced primary decision-makers holding off-farm jobs had lower predicted calf mortality proportions compared to those managed by full-time cattle producers. Higher predicted calf mortality proportions were observed in operations employing a backgrounding system. The study's limitations included potential biases due to its cross-sectional nature and reliance on producer-reported data, which might lead to an underestimation of calf mortality proportions. Also, the limited sample size and missing data might have affected the statistical significance of some variables. This study contributed to the research on cow-calf operation by using a fractional logit model to analyze the correlation between risk factors and calf mortality proportions, and by identifying novel herd-level risk factors. It provided a basis for future research aimed at developing empirically-based management strategies to optimize calf health outcomes.

A scoping review of neonatal calf diarrhea case definitions

Various case descriptions and scoring systems have been used to define neonatal calf diarrhea (NCD) and diverse diarrhea-related outcomes are reported, which limits direct comparison between studies. Therefore, the objective of this scoping review was to characterize the case definitions used for NCD and describe diarrhea-related outcomes to inform future efforts towards standardization. A literature search identified articles using 3 databases (Medline, CAB Direct, Agricola), along with Google and Google Scholar. This returned 16,854 unique articles, which were then screened for eligibility by two independent reviewers, resulting in 555 being selected for data extraction. Among articles, the study populations included mostly dairy-breed calves (88%; n = 486) while the remainder evaluated beef, crossbred, or dual purpose beef/dairy calves (10%; n = 53), or did not report breed (3%; n = 16). Studies used between 1 and 8 metrics to define NCD, with 933 unique metrics extracted in total. The most common metric was fecal consistency alone (30%; n = 281), or with at least 1 other metric (26%; n = 241). To define diarrhea, fecal consistency was either described qualitatively (e.g., "profuse liquid feces"), or semi-quantitatively, for example using a scoring system that frequently included 4 levels (n = 208). Some NCD case definitions included fecal color, volume, or odor (10%; n = 98), physical exam parameters (8%; n = 79), the duration of abnormal feces (7%; n = 67), the presence of abnormal contents (e.g., blood, 7%; n = 61), farm treatment records (6%; n = 54), fecal dry matter (1%; n = 12), or another metric (4%; n = 41). One or more references were cited for the NCD case definition by 49% of studies (n = 273/555), with the most common references being Larson et al. (1977) (n = 85), and McGuirk (2008) (n = 59). In the 555 included articles, 979 unique diarrhea-related outcomes were found, most commonly a binary categorization of calves having or not having diarrhea (49%; n = 483). Other articles reported statistical outcomes calculated from fecal scores (16%; n = 159), multiple diarrhea severities (10%; n = 95), or the age calves first developed NCD (8%; n = 76). This review characterized substantial heterogeneity among NCD case definitions and diarrhea-related outcomes, which limits interpretation and comparison of studies. Future work is required to develop and validate reporting standards for NCD to optimize knowledge synthesis and support rigorous and ethical calf health research.

Describing and Characterizing the Literature Regarding Umbilical Health in Intensively Raised Cattle: A Scoping Review

The objective of this scoping review was to describe and characterize the existing literature regarding umbilical health and identify gaps in knowledge. Six databases were searched for studies examining umbilical health in an intensively raised cattle population. There were 4249 articles initially identified; from these, 723 full text articles were then screened, with 150 articles included in the review. Studies were conducted in the USA (n = 41), Brazil (n = 24), Canada (n = 13), UK (n = 10), and 37 additional countries. Seventeen were classified as descriptive, 24 were clinical trials, and 109 were analytical observational studies. Umbilical outcomes evaluated in descriptive studies were infection (n = 11), parasitic infection (n = 5), and hernias (n = 2). Of the clinical trials, only one examined treatment of navel infections; the remainder evaluated preventative management factors for navel health outcomes (including infections (n = 17), myiasis (n = 3), measurements (n = 5), hernias (n = 1), and edema (n = 1)). Analytical observational studies examined risk factors for umbilical health (n = 60) and umbilical health as a risk factor (n = 60). Studies examining risk factors for umbilical health included navel health outcomes of infections (n = 28; 11 of which were not further defined), hernias (n = 8), scoring the navel sheath/flap size (n = 16), myiasis (n = 2), and measurements (n = 6). Studies examining umbilical health as a risk factor defined these risk factors as infection (n = 39; of which 13 were not further defined), hernias (n = 8; of which 4 were not further defined), navel dipping (n = 12), navel/sheath scores as part of conformation classification for breeding (n = 2), measurements (n = 3), and umbilical cord drying times (n = 2). This review highlights the areas in need of future umbilical health research such as clinical trials evaluating the efficacy of different treatments for umbilical infection. It also emphasizes the importance for future studies to clearly define umbilical health outcomes of interest, and consider standardization of these measures, including time at risk.

Single-dose meloxicam treatment improves standing ability of low-vitality dairy calves

A promising strategy to improve newborn calf survival could be the administration of nonsteroidal antiinflammatory drugs (NSAID) especially in cases of low vitality calves born from difficult calvings. The objective of this clinical trial was to determine the effect of a single-dose meloxicam treatment [target dosage = 0.5 mg/kg ad usum veterinarium (A.U.V.) injection] on parameters of lying behavior of Holstein-Friesian dairy calves (n = 180) born to eutocic (n = 98) compared with dystocic dams (n = 82). Animal-based measures included newborn calf vitality (low, 1-6 scores; normal, 7-12 scores, scored immediately after birth), calf sex and birth weight, parity of the dam, and early maternal behavior (the time spent licking the calf). Parameters of the complex lying behavior were recorded during the first 48 h after delivery and included (1) the time spent standing, (2) lying down frequency, (3) the longest standing bout, (4) the average duration of standing bouts, (5) the first successful standing, and (6) the first attempt to stand. None of the parameters related to lying behavior were influenced by the parity of the dam, calf sex, or birth weight and maternal grooming behavior. The latency and the first attempt to stand were not influenced by the NSAID treatment; however, the time spent standing, the longest standing bout, and the average duration of standing indicated increased standing ability of meloxicam-treated calves with low vitality, but not in normal-vitality calves. The latency to stand and first attempt to stand were both increased by dystocia. Based on the present findings, sensory measurement of parameters of lying behavior during the immediate neonatal period might be useful to evaluate the efficiency of NSAID protocols. A single-dose meloxicam treatment showed considerable promise for improving standing ability of low-vitality calves.

Pre-Weaned Calf Rearing on Northern Irish Dairy Farms: Part 1. A Description of Calf Management and Housing Design

The first few months of life are of great importance to the longevity and lifetime performance of dairy cows. The nutrition, environment and healthcare management of heifer calves must be sufficient to minimise exposure to stress and disease and enable them to perform to their genetic potential. Lack of reporting of farm management practices in Northern Ireland (NI) makes it difficult to understand where issues impacting health, welfare and performance may occur in the rearing process. The objective of this study was to investigate housing design and management practices of calves on 66 dairy farms across NI over a 3-month period and also identify areas that may cause high risk of poor health and performance in dairy calves. An initial survey was used to detail housing and management practices, with two subsequent visits to each farm used to collect animal and housing-based measurements linked to hygiene management, animal health and performance. Large variations in key elements such as weaning criteria and method, calf grouping method used, nutritional feed plane, and routine hygiene management were identified. The specification of housing, in particular ventilation and stocking density, was highlighted as a potential limiting factor for calf health and performance. Lack of measurement of nutritional inputs, hygiene management practices and calf performance was observed. This poses a risk to farmers' ability to ensure the effectiveness of key management strategies and recognise poor calf performance and health.

An Investigation into the Perceptions of Veterinarians towards Perioperative Pain Management in Calves

Simple Summary

Despite developments in animal welfare science regarding perioperative pain management in calves (Bos taurus), there are concerns that current knowledge has not been adopted in practice. Given that the perceptions of veterinarians have implications for how the welfare needs of calves are assessed and managed in practice, this study sought to quantify veterinary perceptions towards perioperative pain management in calves, including barriers to its use and whether demographic differences may influence those perceptions. A nationwide survey was electronically distributed to veterinarians registered with the Veterinary Council of New Zealand. Veterinarians largely associated multimodal pain management with the greatest reduction in perioperative pain. Most veterinarians also perceived that postprocedural pain persists beyond 24 h for disbudding and castration and did not support the use of differential treatment based on developmental age. Despite this, certain barriers were identified for their potential to inhibit the use of pain management on-farm. While demographic differences were found to influence veterinary perceptions towards perioperative pain management, the findings revealed considerable support among veterinarians for improving pain mitigation in calves. Given the opportunity, veterinarians in New Zealand would likely support strengthening the minimum provisions afforded to calves in practice and policy.

Abstract

While veterinarians are instrumental to the welfare of calves (Bos taurus), limited knowledge exists concerning veterinary perceptions towards perioperative pain management in calves. As a part of a larger, nationwide study investigating the perceptions of veterinarians towards calf welfare, the current work sought to quantify veterinary perceptions towards perioperative pain management, including barriers to its use, and investigate demographic influences affecting those perceptions. An electronic mixed-methods survey was completed by 104 veterinarians registered with the Veterinary Council of New Zealand. The current work revealed that most veterinarians considered a multimodal approach as the most effective method for ameliorating perioperative pain in calves, rejected the practice of differential treatment based on developmental age, and perceived that postprocedural pain persists beyond 24 h for the majority of procedures included in the survey. Despite this, veterinarians identified certain barriers that may inhibit the provision of pain mitigation on-farm, including costs, inadequate recognition of pain, and ingrained farming practices. Certain demographic effects were found to influence perceptions towards perioperative pain management, including gender, the number of years since graduation, and species emphasis. Nevertheless, the current work demonstrated considerable support among veterinarians to improve pain management protocols during routine husbandry procedures. The asymmetries that exist between the current minimum provisions of perioperative pain management and veterinary perspectives suggest that substantive improvements are necessary in order to reconcile New Zealand’s existing regulatory regime with developments in scientific knowledge.

Comparison of a traditional bovine respiratory disease control regimen with a targeted program based upon individualized risk predictions generated by the Whisper On Arrival technology

The study objective was to determine if cattle health and performance comparing a targeted bovine respiratory disease (BRD) control program based on individualized risk prediction generated by a novel technology (Whisper On Arrival) was superior to a negative control (no metaphylaxis) yet no different than a positive control (conventional BRD control; 100% application). Across four study sites, auction market-derived beef calves were randomly allocated to one of four BRD control treatment groups: 1) Negative control (Saline), 2) Positive control (Tildipirosin [TIL] to 100% of the group), 3) Whisper-high (±TIL based on conservative algorithm threshold), and 4) Whisper-low (±TIL based on aggressive algorithm threshold). Within either Whisper On Arrival group, only calves predicted to be above the algorithm threshold by the technology (determined a priori) were administered TIL leaving the remainder untreated. Cattle were followed to either a short-term timepoint (50 or 60 d; health outcomes, all sites; feed performance outcomes, two sites) or to closeout (two sites). Data were analyzed as a completely randomized block design separately at each site. Across all sites, BRD control antibiotic use was reduced by 11% to 43% between the two Whisper On Arrival treatment groups compared to the positive control. The positive control and both Whisper On Arrival groups reduced (P ≤ 0.05) BRD morbidity compared to negative controls at both the short-term timepoint at three of the four sites and at closeout at one of two sites. The positive control and both Whisper-managed groups had improved (P ≤ 0.05) average daily gain (ADG), dry-matter intake (DMI), and feed efficiency compared to negative controls at the short-term timepoint at one of two sites. At closeout, the positive control and both Whisper-managed groups improved (P ≤ 0.05) ADG (deads-in) compared to the negative control at one of the two sites. At one of two sites, the positive control and the Whisper-high group displayed an improvement (P ≤ 0.05) in hot carcass weight compared to the negative control. The Whisper On Arrival technology maintained the benefits of a conventional BRD control program yet reduced BRD control antibiotic use by 11% to 43%. This technology maintained the benefits of a conventional BRD control program while reducing antibiotic costs to the producer and supporting judicious antimicrobial use.

Assessment of Plasma Zinc and Total Leukocyte Count in Calves Experimentally Infected with Mannheimia haemolytica

Mannheimia haemolytica is the main bacterial pathogen isolated in bovine respiratory disease (BRD), a common disease affecting calves before weaning. Previous research has shown that experimental infection with bovine herpesvirus 1, a respiratory virus, decreases plasma zinc (Zn) levels. However, changes in plasma Zn concentrations in calves experimentally infected with M. haemolytica have not been studied thus far. The objective of this study was to evaluate the effect of experimental infection with M. haemolytica on plasma Zn concentration in calves. Total leukocyte count and bovine respiratory disease (BRD) clinical score were also evaluated. We conducted a 6-day trial in 14 male Holstein calves randomly assigned to one of two groups, experimental (EG, n = 8) and control (CG, n = 6). Animals in EG were intrabronchially inoculated with M. haemolytica (6.5 × 10⁶ CFU/mL) on day 0 of the trial. Plasma Zn levels were affected by time, treatment, and time by treatment interaction, being lower in EG compared with CG on days 1, 2, and 3. Differences in total leukocyte count were significant on day 1, observing a tendency on day 3. BRD clinical score differed between groups, being higher in EG throughout the trial. We conclude that experimental M. haemolytica infection reduced plasma Zn concentration in clinically ill calves, suggesting that the clinical condition of animals (healthy/ill) should be considered to better interpret plasma Zn values.

Effects of omega-3 fatty acids on immune, health and growth variables in veal calves

Under the present intensive rearing conditions, calves face a series of stressors and multiple pathogens often necessitating antimicrobial use. Multiple feed additives are currently explored for their ability to prevent disease and limit the use of antimicrobials. Supplementation of the polyunsaturated long chain n-3 fatty acids eicosapentaenoic (EPA) and docohexaenoic (DHA) from marine origin has been proposed as a strategy to improve immune function and prevent excessive inflammation reactions. The aim of this randomized clinical trial was to explore the effects of n-3 fatty acids (PUFAs) used as feed supplement on health, production and immune variables in a veal calf setting. One hundred-seventy calves were randomly assigned to 3 treatment groups: microalgae (MA, n = 57, 2.5 g DHA/animal/day), fish oil (FO, n = 57, 2.5 g EPA + DHA/animal/day)] and a control group (CON, n = 56). Average daily gain (ADG), bodyweight at 12 weeks on feed and slaughter weight were determined. Health monitoring consisted of recording of clinical signs and repeated thoracic ultrasonography. After 5, 8 and 11 weeks of supplementation, the function of neutrophils, monocytes and peripheral blood mononuclear cells (PBMCs) was evaluated ex vivo by measuring reactive oxygen species (ROS) production by neutrophils and monocytes and proliferation of and cytokine release by PBMCs. Under the field conditions of this study, dietary supplementation of MA and FO showed very limited immunomodulatory effects. Feeding MA led to increased ROS production by neutrophils, Estimate (E) = 0.38, Standard Error (SE) = 0.14; P < 0.05, compared to the control calves after 5 weeks of in-feed supplementation. FO reduced IL-6 secretion E= -0.29, SE= 0.11; P < 0.05 compared to MA treated animals after 11 weeks on feed. Health and production variables were unaffected by treatments. The doses of EPA and DHA used in this study did not cause immunomodulatory changes in highly stressed calves to such an extent that this led to better health or growth of animals.

Vaccinating Calves in the Face of Maternal Antibodies: Challenges and Opportunities

A growing body of evidence has shown that calves can mount an immune response when vaccinated in the face of maternal antibodies (IFOMA), albeit inconsistently and often in ways that differ from seronegative calves or older cattle. Several previous reviews have endeavored to explain bovine neonatal immunology and have documented the issue of vaccinating young calves. However, as preweaning vaccination becomes more common in both beef and dairy production systems, so too has research on the impacts of such vaccination programs. This article aims to briefly review the challenges and opportunities for vaccinating calves IFOMA.

A randomised controlled trial investigating the effects of administering a non-steroidal anti-inflammatory drug to beef calves assisted at birth and risk factors associated with passive immunity, health, and growth

BACKGROUND

The objectives of this study were to investigate the impact of pain mitigation at birth to assisted beef calves and determine the risk factors associated with transfer of passive immunity (TPI), health, and growth.

METHODS

Two hundred and thirty cow-calf pairs requiring calving assistance were enrolled. Calves were randomised to receive meloxicam (0.5 mg/kg) or an equivalent volume of placebo subcutaneously at birth. Calf blood samples were collected between one and seven days of age to determine serum immunoglobulin (IgG) concentration. Colostrum intake, treatment for disease, mortality, and weaning weights were recorded. Multilevel linear or logistic regression models were used to determine the effects of meloxicam and to identify risk factors.

RESULTS

There was no effect of meloxicam on serum IgG concentrations, average daily gain (ADG), or risk of inadequate TPI (serum IgG concentration <24 g/l), treatment for disease, or mortality (P>0.05). Bottle or tube feeding calves were associated with decreased serum IgG concentrations (P=0.01) compared with nursing. Calves with an incomplete tongue withdrawal reflex had higher odds of being treated for disease compared with those with complete withdrawal (P=0.009). Being born meconium-stained and having decreased serum IgG concentrations were associated with an increased risk of mortality (P=0.03). Being born of a mature cow, having a higher birth weight, and increased serum IgG concentrations were associated with greater ADG to weaning (P<0.05).

CONCLUSION

Vigour assessment at birth along with good colostrum management may be important to improve TPI and health in high-risk calves such as those assisted at birth.

Mortality and Morbidity of Beef Calves in Free-Range Farms in Alentejo, Portugal-A Preliminary Study

Extensive cow-calf beef cattle farms play a significant role in Portuguese livestock production, but records of important production variables, such as calf mortality, are scarce. To assess herd-level calf mortality and its potential economic impact, farmers from the Alentejo region were asked to fill a questionnaire regarding herd size, feeding and reproductive management practices, calf mortality (from birth to weaning), and detection of the main morbidity causes, as well as of sudden, unexplained deaths during the previous 12 months. Farmers were also requested to quantitatively assess the economic impact of calf mortality on their annual revenue. In the majority of farms, the herd size was larger than 100 animals. The median stocking rate was 0.41 adult animals/hectare, and 70% of farmers stated their farm was self-sufficient in forage. The percent of live births that resulted in weaned calves averaged 94.3%, which led to the assumption of a 5.7% calf mortality rate from birth to weaning. In the previous 12 months, 78.8% of the farms identified at least one case of calf diarrhea, 60.7% identified at least one case of respiratory disease, and 82.1% had at least one sudden, unexplained calf death. As expected, farmers that assessed a higher impact of calf losses on their annual economic revenue were also those who reported higher incidences of calf diarrhea, respiratory disease, and sudden, unexplained deaths. One-quarter of the farmers were unable to assess the economic impact of calf mortality on the farm's revenue. Herd size appears to have a predictive value on calf mortality in the first month of life, and from 30 days to weaning. The number of sudden, unexplained calf deaths seems to have a predictive value on overall calf mortality (from birth to weaning), suggesting that the farms' management practices probably play an important role in calf mortality throughout the suckling period. Further studies are needed to fully understand calf mortality in Portuguese extensive rearing systems.

Clinical impacts of administering a nonsteroidal anti-inflammatory drug to beef calves after assisted calving on pain and inflammation, passive immunity, health, and growth

Assisted calves are often born weak, injured, or oxygen deprived and have a higher risk of morbidity and mortality. The objective was to investigate the impact of using pain mitigation at birth in assisted beef calves on physiological indicators of pain and inflammation, passive immunity, health, and growth. Thirty-three primiparous cows and their calves requiring assistance at birth on two ranches located in southern Alberta were enrolled. Data collected at birth include date and time of calving, calf sex, meconium staining, presentation of calf, and calving difficulty (easy assist: one person manually delivered the calf; difficult assist: delivery by two or more people, or mechanical assistance). Within 10 min of birth, calves were stratified by calving difficulty, randomized to a medication group, and received a subcutaneous dose of meloxicam (0.5 mg/kg BW) or an equivalent volume of placebo. Cow–calf pairs were then placed in individual box stalls for observation and sampling. At birth, 1, 4, and 24 h after birth, heart rate, respiratory rate, and rectal temperature were assessed and blood samples collected to measure indicators of pain and inflammation (cortisol, corticosterone, substance P, and haptoglobin). Serum IgG concentration and failed transfer of passive immunity (serum IgG concentration <24 g/L) were assessed in the 24-h blood samples. Preweaning treatment for disease and mortality information was collected and calves were weighed at 7 to 10 d of age and at weaning. Of the 33 calves enrolled, 17 calves received meloxicam and 16 calves received a placebo. Meloxicam-medicated calves had significantly greater ADG to 7 to 10 d of age (P = 0.05) (mean = 0.9 kg/d; SE = 0.10) compared with placebo-medicated calves (mean = 0.6 kg/d; SE = 0.12). There was no significant effect of meloxicam on physiological indicators of pain and inflammation, standing or nursing by 1 h, passive immunity, health outcomes, or ADG to weaning (P > 0.1). Although this was a small sample population, meloxicam given to assisted calves at birth improved ADG in the first week of life, which may indicate an important production management tool for improving well-being in assisted calves.

An investigation of dairy calf management practices, colostrum quality, failure of transfer of passive immunity, and occurrence of enteropathogens among Australian dairy farms

Calf preweaning morbidity and mortality risks have been reported as high in several countries, with average values approximating 35 and 7%, respectively. However, limited data are available for calf morbidity and mortality risks on Australian dairy farms. The aims of this study were (1) to investigate current calf management practices on dairy farms in Australia and their association with herd-level morbidity and mortality using a questionnaire-based, cross-sectional study; and (2) to estimate the prevalence of common enteropathogens causing diarrhea, the failure of passive transfer of immunity, and poor colostrum quality in a sample of Australian dairy farms. We analyzed 106 completed questionnaires and samples from 23 farms (202 fecal, 253 calf serum, and 221 colostrum samples). Morbidity and mortality risks reported by farmers in preweaned heifers were 23.8 and 5.6%, respectively. These risks were above the Australian dairy industry targets in 75.5 and 66.7% of respondents. The zoonotic pathogens Cryptosporidium spp. and Salmonella spp. were the most prevalent enteropathogens, with a true prevalence of 40.9 and 25.2%, respectively. Salmonella O-group D was present in 67.9% of Salmonella-positive samples, followed by O-groups B (17.9%) and C (10.7%). Failure of transfer of passive immunity (IgG <10 g/L) was observed in 41.9% of calves (mean herd-level prevalence of 36.2%), and only 19.5% of colostrum samples met the standards for immunoglobulin content and microbiological quality. Collectively, these data indicate that there is still considerable room for improvement in calf-rearing practices on Australian dairy farms, particularly with regard to colostrum management and feeding hygiene.

Benchmarking calving management practices on western Canada cow-calf operations

Benchmarking current calving management practices and herd demographics in the western Canadian cow–calf production system helps to fill the gap in knowledge and understanding of how this production system works. Further investigation into the relationships between management decisions and calf health may guide the development of management practices and protocols to improve calf health, especially in compromised calves after a difficult birth. Therefore, the objectives of this cross-sectional study were to describe current calving management practices on western Canadian cow–calf ranches and to investigate the association of herd demographics with herd-level incidence of calving assistance, morbidity, mortality, and use of calving and colostrum management practices. Cow–calf producers were surveyed in January 2017 regarding herd inventory and management practices during the 2016 calving season. Ninety-seven of 110 producers enrolled in the western Canadian Cow-Calf Surveillance Network responded. Average herd-level incidence of assisted calvings was 4.9% (13.5% heifers, 3.2% cows), stillbirths was 2.1% (3.3% heifers, 1.9% cows), preweaning mortality was 4.5%, and preweaning treatment for disease was 9.4% (3.0% neonatal calf diarrhea, 3.8% bovine respiratory disease, 2.6% other diseases). Greater than 90% of producers assisted calvings and would intervene with colostrum consumption if the calf did not appear to have nursed from its dam. Late calving herds (i.e., started calving in March or later) had significantly lower average herd-level incidence of assistance, treatment for disease, and mortality (P < 0.05). In earlier calving herds (i.e., started calving in January or February) producers had shorter intervals between checking on dams for signs of calving or intervening to assist with a calving (P < 0.05). In early calving herds, producers were more likely to perform hands-on colostrum management techniques such as placing the cow and calf together or feeding stored, frozen colostrum (P < 0.05). There were no associations between herd size and herd-level incidences or management techniques (P > 0.05). This study suggests that in western Canada earlier calving herds are more intensively managed, whereas later calving herds are more extensively managed. Herd demographics may be important to consider when investigating factors associated with management strategies, health, and productivity in cow–calf herds.

Effects of management practices, animal transport and barn climate on animal health and antimicrobial use in Swiss veal calf operations

To assess the effects of transport, management factors and barn climate on calf health, 43 Swiss veal farms (11 large farms fattening ≥100 calves and 32 small farms fattening >20 but <100 calves per year) were monitored in a prospective cohort study over a period of one year. Detailed questionnaires on farm structure, management, housing system and animal health were filled out with the farmers during bimonthly visits, and barn temperature, humidity, ammonia and CO₂ concentrations were measured. Temperature and humidity were also measured continuously over 72 h once each in winter and summer. In addition, calf purchase and transport from birth farm to fattening unit were documented by the farmers, and the study team accompanied one transport per farm whenever possible. Antimicrobial treatment incidence was calculated from the used daily dose (TI_UDD). Risk factors for mortality, average daily weight gain (ADG) and antimicrobial use, as well as factors related to transport and barn climate measures were evaluated with mixed regression models. The overall mortality rate was 5.1% (6.2% in large herds and 3.1% in small ones). Identified risk factors for mortality >3% included a lower number of calves fattened per year and a good hygiene of the feeder. This surprising result was likely due to the fact that the threshold of 3% mortality was rather exceeded in smaller farms. Furthemore, higher temperature variation (range between maximal and minimal temperature over 3 measurement days) in the calf pen was associated with mortality >3% in the univariable analysis. The overall mean ADG was 1.40 ± 0.16 kg. Calf purchase was significantly associated with decreased ADG. The median overall TI_UDD was eight daily doses per calf and year (2.1 in small farms and 26 in large farms, respectively); the main indication for treatment was respiratory disease (81.1%). Risk factors for increased TI were no quarantine upon arrival, access to an outside pen, higher numbers of calves per drinking nipple, mechanical ventilation, vaccination against bovine respiratory disease, and a maximum ammonia value >10 ppm in the calf pen. In addition, a higher number of birth farms and calf purchase from markets were associated with increased TI in the univariable analysis. The identified risk factors associated with increased TI and mortality and with decreased ADG should be addressed in priority in veal calf operations to improve calf health and reduce antimicrobial use.

Risk factors associated with animal mortality in pasture-based, seasonal-calving dairy and beef herds

Animal mortality is indicative of animal health and welfare standards, which are of growing concern to the agricultural industry. The objective of the present study was to ascertain risk factors associated with mortality at multiple life stages in pasture-based, seasonal-calving dairy and beef herds. Males and females were stratified into seven life stages based on age (0 to 2 d, 3 to 7 d, 8 to 30 d, 31 to 182 d, 183 to 365 d, 366 to 730 d, and 731 to 1,095 d) whereas females with ≥1 calving event were further stratified into five life stages based on cow parity number (1, 2, 3, 4, and 5). Mortality was defined as whether an animal died during each life stage; only animals that either survived the entire duration or died during a life stage were considered. The data, following edits, consisted of 4,404,122 records from 1,358,712 animals. Multivariable logistic regression was used to estimate the logit of the probability of mortality in each life stage separately. The odds of a young animal (i.e., aged ≤ 1,095 d) dying was generally greater if veterinary assistance was required at their birth relative to no assistance (odds ratio [OR]: 3.10 to 31.85), if the animal was a twin relative to a singleton (OR: 1.46 to 2.31) or if the animal was male relative to female (OR: 1.14 to 6.15). Moreover, the odds of a cow (i.e., females with ≥1 calving event) dying were greater when she required veterinary assistance at calving (OR: 2.69 to 7.55) compared with a cow that did not require any assistance, if she produced twin relative to singleton progeny (OR: 1.59 to 2.03) or male relative to female progeny (OR: 1.09 to 1.20). Additionally, the odds of a first or second parity cow dying when she herself had received veterinary assistance at birth were only 0.63 to 0.66 times that of a cow that was provided no assistance at birth. For both young animals and cows, the odds of dying generally increased with herd size, whereas animals residing in expanding herds had lower odds of dying. Results from the present study indicate that the risk factors associated with mortality in pasture-based, seasonal-calving herds are similar to those reported in literature in confinement, nonseasonal-calving herds. Moreover, the present study identifies that these risk factors are similar in both dairy and beef herds, yet the magnitude of the association often differs and also changes with life stage.

Management practices associated with pain in cattle on western Canadian cow-calf operations: A mixed methods study

The implementation of on-farm pain mitigation strategies is dependent on feasibility and importance to producers. Currently, there is a lack of information regarding adoption of management practices associated with pain in cattle within the Canadian beef industry. The objective of this mixed methods study was to describe pain-associated practices implemented on farm and producer perceptions toward pain mitigation strategies. A questionnaire about calving management and calf processing was delivered to 109 cow-calf producers in western Canada. In addition, 15 respondents were purposively selected based on questionnaire responses to participate in individual semistructured, on-farm interviews. The prevalence of pain mitigation strategies used for dystocia and cesarean section by respondents were 46 and 100%, respectively. The majority of operations reported castrating and dehorning calves before 3 mo of age (95 and 89%, respectively). The majority of operations did not use pain mitigation strategies for castration and dehorning (90 and 85%, respectively). Branding was practiced by 57% of respondents, 4% of which used pain mitigation. Thematic content analysis revealed that producers' perception of pain were influenced by what they referred to as "common sense," relatability to cattle, visual evidence of pain, and age of the animal. Factors that influenced participant rationale for the implementation of pain mitigation practices included access to information and resources, age of the animal, benefit to the operation, cost and logistics, market demands, and personal conscience. Overall, management practices were generally in compliance with published Canadian guidelines. Results of this study may provide direction for future policy making, research, and extension efforts to encourage the adoption of pain mitigation strategies.

Management practices associated with stress in cattle on western Canadian cow-calf operations: A mixed methods study

Handling, weaning, and euthanasia are some of the most stressful practices performed on cow-calf operations. Although strategies to minimize stress exist, their use on western Canadian cow-calf operations is unknown. The objectives were to describe current stress-associated practices on western Canadian cow-calf operations, describe producer and operation demographics associated with the use of nonabrupt weaning methods, and explore producer perceptions toward these practices. A questionnaire focusing on stressful management practices was delivered to 109 cow-calf producers in western Canada. Fifteen respondents were purposively selected for individual interviews. The majority of producers reported calves less than 1 wk of age were handled by manual restraint (87%) and those older than 1 wk of age were handled using a cattle squeeze or table. Most producers performed abrupt weaning (70%). Interviewees often mentioned that cost and logistics were major factors in deciding on a weaning strategy. Pasture availability and facilities were viewed as constraints toward the adoption of a nonabrupt weaning method. Animal stress was considered, as producers expressed concern that nonabrupt weaning methods may cause increased stress because of the additional handling required. Producers conveyed that animal age was a major factor that impacted weaning stress and that improved animal performance might motivate them to adopt a nonabrupt weaning strategy. Producers also expressed reluctance to change previously successful traditional approaches. Of respondents, 13% did not euthanize cattle on farm and 8% did not confirm death. Producers interviewed reported that the decision to euthanize cattle on farm was difficult and that veterinary advice was often considered. Factors that influenced their decision to euthanize included the animal's likelihood of recovery and degree of pain and distress. Finally, producers explained that they considered whether the animal was salvageable and able to be transported. Identification of common methods of handling provides focus for future research to determine optimal handling strategies. Identified barriers to nonabrupt weaning may be addressed through research, extension, or policy to encourage the adoption of weaning methods that could improve animal welfare. Confirmation of death after euthanasia was identified as an area that needs to be addressed by producer education to minimize animal stress during on-farm euthanasia.

Evaluation of the effects of colostrum replacer supplementation of the milk replacer ration on the occurrence of disease, antibiotic therapy, and performance of pre-weaned dairy calves

The objective of this study was to evaluate the effects of colostrum supplementation of the milk replacer ration on disease occurrence, antibiotic therapy, and performance of pre-weaned dairy calves with adequate transfer of passive immunity. Two hundred and two 1-d-old Holstein dairy calves were assigned to 1 of 2 groups after arrival to a dairy calf rearing facility. Calves assigned to the control group (n = 100) received milk replacer (28% crude protein and 20% crude fat) without colostrum inclusion twice daily. Calves assigned to the treatment group (n = 102) received 150 g of supplemental colostrum replacer powder added to their milk replacer twice daily for the first 14 d of life. Before group assignment, serum samples were collected from all calves to confirm transfer of passive immunity. Calves were evaluated daily until weaning (56 d of life) for signs of clinical disease as well as any treatment with antibiotics. Presentation of clinical disease and antibiotic treatment was recorded daily by personnel blinded to treatment allocation. Adequate transfer of passive immunity was confirmed in all calves at the start of the study and mean serum IgG values were similar among calves from treatment and control groups. The odds ratios of having abnormal feces and abnormal respiration during the pre-weaning period for calves from the treatment group were 0.15 and 0.46 the odds ratios of calves from the control group, respectively. The odds ratios of receiving antibiotic therapy during the pre-weaning period for calves from the treatment group were 0.09 the odds ratios of calves from the control group. Mean body weight and average daily gain at weaning were not significantly different among calves from the treatment and control groups. Colostrum replacer supplementation of the milk replacer ration was effective in reducing antibiotic therapy and occurrence of disease during the pre-weaning period.