Graduate Student Literature Review: Role of pain mitigation on the welfare of dairy calves undergoing disbudding.

This review synthesizes research findings on the pain and welfare of dairy calves undergoing disbudding procedures. We describe disbudding practices in North America as well as the use and perceptions of pain control for these procedures. Governing bodies across Canada and the United States, including each country's veterinary medical association and nationwide initiatives such as proAction and Farmers Assuring Responsible Management (FARM), recommend or require the use of a local anesthetic, a nonsteroidal anti-inflammatory drug (NSAID), and a sedative for disbudding procedures. Although the use of pain relief for disbudding has increased over the past decade or so, some in the dairy industry still do not believe that pain control for disbudding is necessary. As a painful procedure, disbudding has numerous welfare impacts on the calf both during and following the procedure that can be categorized under all 3 principles of animal welfare: natural living, biological functioning, and affective state. The use of pain control for disbudding; namely, a local anesthetic and NSAID, can improve welfare outcomes such as procedure-induced pain behavior, cortisol concentrations, mechanical nociceptive threshold, emotional states, and so on, compared with no pain control for the procedure. Although extensive research exists on pain control practices for disbudding, this review identified further gaps in knowledge and areas for future research. Mechanical nociceptive threshold can be evaluated around the disbudding wounds and is a reliable test in older calves; however, this outcome in very young calves after caustic paste disbudding has been reported to be inconclusive compared with that in older calves. As well, research evaluating xylazine sedation for disbudding has reported both potentially positive and negative results that are difficult to interpret or base suggestions on for the use of this drug. Finally, wounds caused by disbudding take a long time to heal (up to 13 wk) and have increased sensitivity for the entire healing process. Therefore, future research should aim to (1) determine accurate behavioral tests for calves under 1 wk of age undergoing disbudding to better understand their experience, (2) further attempt to understand the effects of xylazine sedation for disbudding and potential impacts of providing this medication, and (3) determine more ways to reduce the healing time and pain experienced by the calf after disbudding procedures.

Effect of plane of nutrition and analgesic drug treatment on wound healing and pain following cautery disbudding in preweaning dairy calves.

The objective of this study was to determine the effect of a biologically normal plane of nutrition compared with a limited plane on the primary outcome wound healing, and one dose of nonsteroidal anti-inflammatory drug (NSAID) compared with 2 on the secondary outcomes: lying behavior, haptoglobin concentrations, and mechanical nociceptive threshold (MNT) in calves disbudded via cautery iron. Eighty female Holstein calves were enrolled at birth, individually housed, and fed via a Calf Rail system (Förster Technik). A 2 × 2 factorial design was used to assess the effect of plane of nutrition and an additional NSAID. Calves were randomly assigned to a biologically normal plane of nutrition (BN; offered up to 15 L/d) or a limited plane (LP; offered up to 6 L/d) and to receive one or 2 doses of meloxicam. All calves received a lidocaine cornual nerve block and a subcutaneous injection of meloxicam 15 min before cautery disbudding at 18 to 25 d of age, and half the calves received an additional injection of meloxicam (0.5 mg/kg) 3 d after disbudding. Tissue type present, wound diameter, and wound depth were evaluated 2 times per week for 7 to 8 wk as measures of wound healing, lying behavior was recorded beginning 1 to 2 wk before disbudding until 7 to 8 wk after as a behavioral indicator of pain, haptoglobin concentrations were measured once per day for 7 d after disbudding, and MNT was evaluated 2 times/wk for 3 wk. Survival analyses were analyzed using Cox regression models (wound healing) and continuous data were analyzed using mixed-effect linear regression models. Only 12% of horn buds were completely healed by 7 to 8 wk after disbudding and 54% had re-epithelized at this time. At any time, wounds from BN calves were more likely to have had re-epithelization occur compared with wounds from LP calves (hazard ratio: 1.93, 95% CI: 1.18-3.14). Wounds from calves that received only one dose of NSAID were more likely to have re-epithelization occur, compared with wounds from calves given 2 doses (hazard ratio: 1.87, 95% CI: 1.15-3.05). Wounds from BN calves had smaller diameters and depths over time beginning on wk 3 compared with LP calves. Wounds from calves that received an additional NSAID had larger diameters and depths over time beginning on wk 4 and 3 respectively, compared with calves that only received one dose of NSAID. Calves that received an extra NSAID tended to be less sensitive 7, 10, and 17 d after disbudding compared with calves that only received one dose and spent less time lying in the week after disbudding. Calves on the BN milk program were more active compared with LP calves with lower lying times, fewer lying bouts per day, and longer average lying bouts. Our results indicate that a BN milk feeding program for calves can result in faster healing times and more activity, and that providing an extra NSAID 3 d after disbudding appears to slow the healing process but may result in less pain experienced by the calf 1 to 2 wk after the procedure. This study is also among the first to demonstrate that after the complete removal of the horn bud, wounds can take more than 8 weeks to re-epithelize and fully heal.

Randomized controlled trial assessing the effects of xylazine sedation in 2- to 6-week-old dairy calves disbudded with a cautery iron.

The use of local anesthesia and a nonsteroidal anti-inflammatory drug (NSAID) can reduce indicators of pain and inflammation and encourage self-rewarding behavior in calves following disbudding. Although the use of sedation may be recommended as a best practice for disbudding, there is little research in this area. The objective of this study was to evaluate the effects of xylazine sedation in conjunction with a local anesthetic and an NSAID in calves undergoing cautery disbudding. One hundred twenty-two group-housed female and male Holstein calves fed milk with automated feeders, aged 13 to 44 d, were enrolled over 9 replicates and randomly allocated to 1 of 2 treatments: (1) sedated: lidocaine cornual nerve block, 0.5 mg/kg meloxicam (administered subcutaneously) and 0.2 mg/kg xylazine (administered intramuscularly), or (2) nonsedated: lidocaine cornual nerve block and meloxicam. Outcomes collected consisted of feeding behavior (collected using automated milk feeders), latency to drink milk following disbudding, play behavior (induced by adding bedding), lying behavior, mechanical nociceptive threshold (MNT, measured using a pressure force algometer), struggling behavior during disbudding, length of time to administer the nerve block, length of time to disbud, and serum haptoglobin concentrations. Data were analyzed using mixed models with a fixed effect for baseline values and a random effect for trial replicate. Linear regression was used to assess continuous outcomes, logistic regression for binary outcomes, and Poisson and negative binomial models for count data with negative binomial models used if the over dispersion term was significant. There were no detected differences between the treatment groups in mean daily milk consumption in the 72-h following disbudding. Sedated calves had reduced average milk drinking speed from 0 to 24 h and 24 to 48 h following disbudding compared with nonsedated calves, but no difference was detected from 48 to 72 h. Sedated calves had reduced MNT at 0, 60, and 240 min after disbudding, but no differences were detected between groups at 24 h after disbudding. Nonsedated calves had 4.5 times the odds (95% CI: 1.5-13.2) of struggling more than twice during the disbudding procedure compared with sedated calves, and it took less time to administer a nerve block to sedated calves compared with nonsedated. At +3 h, nonsedated calves were 79 times (95% CI: 22.4 to 279.2) more likely to play compared with sedated calves, and 24 h after disbudding, sedated calves were 2 times more likely to play compared with nonsedated calves (95% CI: 0.93-4.3). The results indicate that calves sedated with xylazine for cautery disbudding responded less to painful stimuli (disbudding and MNT) both during and following the procedure and had a higher rate of play behavior 24 h following sedation compared with the nonsedated calves, but xylazine may also have a prolonged carryover effect that affects suckling behavior for 48 h following sedation.

Randomized control trial assessing the efficacy of pain control strategies for caustic paste disbudding in dairy calves younger than 9 days of age.

Disbudding is a common procedure practiced in the dairy industry and is known to cause pain when performed without pain control. Dairy producers who disbud calves with caustic paste are less likely to provide pain control than those using cautery. Little research has been conducted on pain control for caustic paste disbudding and no studies have specifically examined calves under 9 d of age. The objective of this study was to evaluate the efficacy of local anesthesia and nonsteroidal anti-inflammatory drug analgesia on indicators of pain and inflammation in dairy calves disbudded using caustic paste. One hundred forty Holstein heifer calves 1 to 9 d of age were enrolled in 28 blocks and randomly allocated to 1 of 5 treatments: sham control (SH); positive control (POS); lidocaine cornual nerve block (LC); meloxicam (MEL); and lidocaine cornual nerve block plus meloxicam (LCM). We measured outcomes including serum cortisol and haptoglobin, pressure sensitivity, and lying behavior. Data were analyzed using mixed linear regression models with treatment as a fixed effect, baseline values as a covariate, and trial block as a random effect. Compared with the POS group, the LCM group had reduced serum cortisol at 15, 30, 45, and 60 min post-disbudding; cortisol values were not different between LC, LCM, and SH calves at these time points. At 60, 90, 120, and 180 min post-disbudding, LCM calves had reduced cortisol compared with LC calves, whereas, values did not differ between LCM and SH calves at these time points. At 3 to 4 d post-disbudding, the LCM group tended to have reduced haptoglobin, but no differences were found between groups at 180 min and 7 d post-disbudding. At 60, 90, and 120 min post-disbudding, LC and LCM treated calves had decreased pressure sensitivity compared with other groups. No differences were seen in pressure sensitivity between groups at 180 min, 3 to 4 or 7 d post-disbudding. No differences in lying behavior were found between treatment groups on any of the 7 d following disbudding. These findings demonstrate that the combination of a local anesthetic with a nonsteroidal anti-inflammatory drug is beneficial for reducing indicators of pain and inflammation in young calves disbudded with caustic paste.

Experiences, attitudes, and perceptions of accredited advisors towards a voluntary producer training program for Canadian Quality Milk.

This study was conducted to understand the experiences, attitudes, and perceptions of advisors towards the voluntary producer training program offered in Ontario prior to the first Canadian Quality Milk validation. A survey was used to gather advisor opinions and was sent by e-mail to all advisors listed on the Dairy Farmers of Ontario (DFO) website. ANOVA and Chi-Square analyses were utilized to identify significant differences among respondent groups (veterinarian, non-veterinarian, and unidentified), linear regression was used to evaluate associations with the number of producers an advisor trained, and logistic regression was performed to evaluate associations with advisor opinions. Advisors who trained more producers were more likely to provide both classroom and on-farm sessions, train producers with greater consistency in audit results, and remain in communication with producers they had trained. Advisor-suggested improvements for similar programs in the future were increased compensation, more use of interactive learning, and re-structured advisor training.

Expériences, attitudes, et perceptions de conseillers accrédités envers un programme de formation volontaire des producteurs pour Lait canadien de qualité. La présente étude a été menée pour comprendre les expériences, attitudes et perceptions des conseillers envers le programme volontaire de formation offert en Ontario avant la première validation de Lait canadien de qualité. Un sondage a été utilisé pour récolter les opinions des conseillers et fut acheminé par courriel à tous les conseillers listés sur le site web des Producteurs de lait de l'Ontario (DFO). Des analyses ANOVA et Chi-carré ont été utilisées pour identifier les différences significatives parmi les groupes de répondants (vétérinaires, non-vétérinaires, et non-identifiés), une régression linéaire a été utilisée pour évaluer les associations avec le nombre de producteurs et de conseillers formés, et une régression logistique fut effectuée pour évaluer les associations avec les opinions des conseillers. Les conseillers qui ont formé plus de producteurs étaient plus susceptibles à fournir des sessions de formation en classe et à la ferme, de former les producteurs avec une plus grande constance dans les résultats d'audits, et de demeurer en communication avec les producteurs qu'ils avaient formés. Des améliorations suggérées par les conseillers pour des programmes similaires futurs étaient d'augmenter le montant des compensations, une plus grande utilisation d'apprentissage interactif, et une restructuration de la formation des conseillers.(Traduit par Dr Serge Messier).

Comparison of online, hands-on, and a combined approach for teaching cautery disbudding technique to dairy producers.

The use of pain control for disbudding and dehorning is important from both an animal and industry perspective. Best practices include the use of local anesthetic, commonly given as a cornual nerve block (CNB), and a nonsteroidal anti-inflammatory drug. The proportion is decreasing, but many dairy producers do not use local anesthesia, perhaps in part due to lack of knowledge of the CNB technique. Although this skill is typically learned in person from a veterinarian, alternative methods may be useful. The objective of this trial was to determine if there were differences in the efficacy of online training (n = 23), hands-on training (n = 20), and a combined approach (n = 23) for teaching producers to successfully administer a CNB and disbud a calf. The primary outcome was block efficacy, defined as a lack of established pain behaviors during iron application. Secondary outcomes were background knowledge (assessed by a written quiz), CNB and disbudding technique (evaluated by rubric scoring), time taken, and self-confidence before and after evaluation. Associations between training group and outcome were assessed with logistic regression, ordered logistic regression, and Cox-proportional hazard models, with a random effect for workshop. Block efficacy was not different between training groups, with 91% successful in both combined and online groups, and 75% in the hands-on trained group. Online learners had poorer technical scores than hands-on trainees. The combined group was not different from hands-on. Time to block completion tended to be longer for the online group (62 ± 11 s), whereas time to disbudding completion was not different between hands-on (41 ± 5 s) or combined trainees (41 ± 5 s). The combined group had the highest pre-evaluation confidence score, and remained higher after evaluation than online but was not different than hands-on. Although we saw some statistical differences between groups, absolute differences were small and block efficacy was similar. This suggests online training can be a useful tool for motivated producers who lack access to hands-on training.

Effects of local anesthetic or systemic analgesia on pain associated with cautery disbudding in calves: A systematic review and meta-analysis.

Disbudding is a common management procedure performed on dairy farms and, when done without pain mitigation, is viewed as a key welfare issue. Use of pain control has increased in recent years, but full adoption of anesthesia and analgesia by veterinarians or dairy producers has not been achieved. This may in part be due to the lack of a consistent recommendations of treatment protocols between studies examining pain control methods for disbudding. The objective of this systematic review was to examine the effects of these pain control practices for the most common method of disbudding, cautery, on outcomes associated with disbudding pain in calves. The outcomes were plasma cortisol concentrations, pressure sensitivity of the horn bud area, and validated pain behaviors (ear flick, head shake, head rub, foot stamp, and vocalization). Intervention studies describing cautery disbudding in calves 12 wk of age or younger were eligible, provided they compared local anesthesia, nonsteroidal anti-inflammatory drug (NSAID), or local anesthesia and NSAID to 1 or more of local anesthesia, NSAID, or no pain control. The search strategy used the Agricola, Medline (via OvidSP), and Web of Science databases, as well as the Searchable Proceedings of Animal Conferences (S-PAC), ProQuest Dissertations and Theses Database, and Open Access Theses and Dissertations. Meta-analysis was performed for all outcomes measured at similar time points with more than 2 studies. Local anesthetic was associated with reduced plasma cortisol until 2 h postdisbudding; however, a rise in cortisol was observed in the meta-analysis of studies reporting at 4 h postdisbudding. Heterogeneity was present in several of the analyses for this comparison. The addition of NSAID to local anesthetic showed reduction in plasma cortisol at 4 h, and a reduction in pressure sensitivity and pain behaviors in some analyses between 3 and 6 h postdisbudding. Heterogeneity was present in some meta-analyses, including several using pain behavior outcomes. This may reflect the variation in measurement time periods for behavioral measures between studies, as well as differences among NSAID treatments. Overall, a protective effect of local anesthetic was seen for the acute pain of cautery disbudding, and the delayed rise in cortisol was mitigated by the addition of an NSAID, which also reduced other signs of pain, including pressure sensitivity and pain behaviors. Based on these findings, we recommend use of local anesthetic and an NSAID as best practices for pain mitigation for cautery disbudding of calves 12 wk of age or less. The magnitude and duration of the effect of NSAID treatment was not possible to deduce from the literature because wide variation existed between studies. We recommend consideration of more standardized outcome measurements, especially for pain behaviors. Adherence to reporting guidelines by authors would help ensure more transparent and complete information is available to end users.

Clinical trial of local anesthetic protocols for acute pain associated with caustic paste disbudding in dairy calves.

Caustic paste disbudding is becoming more commonplace in North America. A large body of work has examined pain control for cautery disbudding and surgical dehorning, but fewer studies have evaluated pain control for caustic paste disbudding, and results conflict regarding benefits of local anesthesia. In humans, the pain associated with a caustic, chemical burn can differ in nature, duration, and intensity compared with a thermal burn. The objective of this clinical trial was to evaluate the effects of either a lidocaine cornual nerve block or a topical anesthetic incorporated into caustic paste on the acute pain of caustic paste disbudding. Seventy-two Holstein-Friesian calves housed in groups with an automated milk feeder were enrolled into 18 replicates balanced on age and assigned to 1 of 4 treatments: sham (S), placebo paste and a saline cornual block; topical (T), a novel caustic paste containing lidocaine and prilocaine, and a saline cornual block; cornual block (B), commercial caustic paste and a lidocaine cornual nerve block; and positive (P), commercial caustic paste and a saline cornual block. All calves received 0.5 mg/kg of meloxicam SC at the time of the block. Researchers were blinded to treatment group. Primary outcomes were validated pain behavior responses and pain sensitivity measured by algometry. Secondary outcomes consisted of respiratory and heart rate, latency to approach the evaluator, play behavior, feeding behavior, and standing and lying bout characteristics. Data were analyzed using linear, Poisson, and negative binomial regression models. Cornual-blocked calves had less pain sensitivity to 180 min after disbudding than all other groups; T and P calves had more pain sensitivity than S calves for the same time period. Compared with T and P calves, B and S calves had fewer pain behaviors until 120 min postdisbudding, decreased respiratory and heart rates, and a shorter latency to feed. The S calves exhibited more play behavior than other groups. Caustic paste appears to be acutely painful for at least 180 min, and this is reduced by a cornual nerve block but not by our novel paste. Because caustic paste may result in a different pain experience than cautery, use of a variety of metrics assessing affective state, physiologic responses, and normal behaviors, such as feeding and lying, should be included into future trials to help assess the welfare of calves disbudded by this method. We recommend that calves disbudded with caustic paste receive local anesthetic with a cornual nerve block as well as a nonsteroidal anti-inflammatory drug to mitigate acute pain.

Comparison of an online learning module to hands-on training in teaching a cautery disbudding technique for dairy calves including cornual nerve block application.

Disbudding and dehorning are common procedures on dairy farms. In a recent survey of Ontario dairy producers, 38% reported not using local anesthetic for these procedures. Use of pain control is important for both calf welfare and industry sustainability. Use of local anesthetic requires technical training, typically provided by a veterinarian, although online training videos also exist. Neither method has been studied for efficacy. Our objective was to compare an online module to hands-on training in teaching naïve participants (veterinary students) to effectively carry out a cornual nerve block and disbud a dairy calf. Participants were assigned to either an online or hands-on training group. Although no statistical differences were seen in success of the nerve block, online learners were less confident and had poorer technical skills. While online learning was surprisingly effective for a psycho-motor skill, best practices should include hands-on training.

Comparaison d'un module d'apprentissage en ligne avec une formation pratique pour l'enseignement de la technique d'enlèvement des bourgeons par cautérisation pour les vaches laitières incluant l'application d'un bloc du nerf de la corne. L'enlèvement des bourgeons et l'écornage sont des interventions fréquentes dans les fermes laitières. Dans une étude récente auprès des producteurs laitiers de l'Ontario, 38 % ont signalé ne pas utiliser d'anesthésie locale pour ces interventions. Le recours au contrôle de la douleur est important pour le bien-être du veau et la durabilité de l'industrie. L'utilisation de l'anesthésie locale exige une formation technique, qui est habituellement fournie par un médecin vétérinaire, quoique des vidéos de formation en ligne existent également. Ni l'une ni l'autre des méthodes d'enseignement n'a été étudiée pour en évaluer l'efficacité. Notre objectif consistait à comparer le module en ligne à une formation pratique pour l'enseignement des participants non initiés (étudiants en médecine vétérinaire) afin de réaliser efficacement un bloc du nerf de la corne et d'enlever le bourgeon chez un veau laitier. Les participants ont été assignés au hasard à un groupe de traitement. Même si aucune différence statistique n'a été observée pour le succès du bloc nerveux, les apprenants en ligne manifestaient moins de confiance et avaient des compétences techniques inférieures. Même si l'apprentissage en ligne était étonnamment efficace pour une compétence psychomotrice, les meilleures pratiques devraient inclure une formation pratique.(Traduit par Isabelle Vallières).

Estimated antimicrobial dispensing frequency and preferences for lactating cow therapy by Ontario dairy veterinarians.

In this cross-sectional study, data were collected from responses to a questionnaire on dispensing frequencies of antimicrobials used by dairy practitioners in Ontario in dairy cattle in 2001. Data were validated through clinical case scenarios. Respondents reported using antimicrobials across all categories of importance to human medicine (medically important, Categories I to III) with a diversity of treatment combinations and routes of administration. Respondents anticipated that a request for direct veterinary supervision by producers was dependent on case severity, highlighting the importance of on-farm diagnostic and treatment protocols. Knowledge of the antimicrobials used in lactating cow therapy, and their frequency and reasons for use, will provide baseline information and contribute to antimicrobial stewardship in this food-animal production sector.

Estimé de la fréquence de la distribution d'agents antimicrobiens et préférences pour le traitement des vaches laitières par les vétérinaires en Ontario. Cette étude en coupe transversale a été réalisée à partir de réponses recueillies d'un questionnaire qui ciblait les fréquences de dispense d'agents antimicrobiens utilisés chez les vaches laitières par les vétérinaires de la province d'Ontario en 2001. Ces données ont été validées avec l'aide de scénarios de cas cliniques. Les répondants ont indiqué l'utilisation d'antimicrobiens dans toutes les catégories qui sont jugées critiques en médecine humaine (dont les Catégories I à III) avec une diversité de combinaisons de traitements ainsi que de moyens d'administration. Les répondants ont anticipé que ce serait la sévérité d'un cas clinique qui déterminerait si le producteur devait faire une demande de supervision directe d'un vétérinaire sur la ferme. Ceci fait ressortir l'importance des protocoles de diagnostics et de traitements qui se feront dans chaque ferme. La connaissance des sortes d'agents antimicrobiens nécessaires, ainsi que la raison et la fréquence de leur utilisation en thérapie chez la vache laitière lactante, va fournir des renseignements de base et aussi contribuer à la gestion responsable d'agents antimicrobiens dans ce secteur de production animale.(Traduit par les auteurs).

Practices for the disbudding and dehorning of dairy calves by veterinarians and dairy producers in Ontario, Canada.

Disbudding and dehorning dairy calves is very common, despite the introduction of polled genetics to most dairy breeds. Appropriate pain-control practices for these procedures affect both calf welfare and public perception of the dairy industry. Previously published work has shown that North American dairy producers have not widely adopted use of these medications for disbudding or dehorning. However, since the last published work examining these practices in Canada, changes regarding awareness, availability, and future requirements for pain control have occurred in the industry. With this in mind, online and telephone surveys of both veterinarians (n=238) and dairy producers (n=603) in Ontario, Canada, were conducted in the fall of 2014 with a goal of describing current disbudding and dehorning practices and examining factors associated with the adoption of pain control use. Approximately three-quarters of dairy producers reported performing disbudding or dehorning themselves, whereas the remainder used a veterinarian or technician. Almost all (97%) of the veterinarians surveyed reported using local anesthetic, 62% used sedation, and 48% used a nonsteroidal anti-inflammatory drug. Producer use of local anesthetic was 62%, 38% used sedation and 24% used a nonsteroidal anti-inflammatory drug. Seventy-eight percent of veterinarian disbudding or dehorning was done before 8wk of age, whereas 64% of dairy producers performed this procedure before 8wk of age. Seventy-two percent of veterinarians and 63% of producers reported changing their disbudding or dehorning practices over the past 10 yr; of producers that changed their practices, 73% cited their herd veterinarian as influential. The use of pain control described in these surveys is higher than previously reported in Ontario. Identification of factors associated with best practices, or the lack of adoption of these practices, may help veterinarians target appropriate educational opportunities for their dairy clients.

The cost of a case of subclinical ketosis in Canadian dairy herds.

The objective of this study was to develop a model to estimate the cost of a case of subclinical ketosis (SCK) in Canadian dairy herds. Costs were derived from the default inputs, and included increased clinical disease incidence attributable to SCK, $76; longer time to pregnancy, $57; culling and death in early lactation attributable to SCK, $26; milk production loss, $44. Given these figures, the cost of 1 case of SCK was estimated to be $203. Sensitivity analysis showed that the estimated cost of a case of SCK was most sensitive to the herd-level incidence of SCK and the cost of 1 day open. In conclusion, SCK negatively impacts dairy herds and losses are dependent on the herd-level incidence and factors included in the calculation.

Coût d'un cas d'acétonémie subclinique dans les troupeaux laitiers canadiens. L'objectif de cette étude consistait à développer un modèle pour estimer le coût d'un cas d'acétonémie subclinique (ASC) dans les troupeaux laitiers canadiens. Les coûts ont été dérivés des valeurs par défaut et comprenaient l'incidence accrue de maladie clinique attribuable à l'ASC, 76 $; un délai plus long avant la gestation, 57 $; la réforme et la mort au début de la lactation attribuable à l'ASC, 26 $; la perte de production laitière, 44 $. Compte tenu de ces chiffres, le coût de 1 cas d'ASC a été estimé à 203 $. Une analyse de sensibilité a montré que le coût estimé d'un cas d'ASC était le plus sensible à l'incidence de l'ASC au niveau du troupeau et au coût d'une journée ouvrable. En conclusion, l'ASC a un impact négatif sur les troupeaux laitiers et les pertes dépendent de l'incidence au niveau du troupeau et des facteurs inclus dans le calcul.(Traduit par Isabelle Vallières).

Economic value of ionophores and propylene glycol to prevent disease and treat ketosis in Canada.

A partial budget model was developed to evaluate the economic value of Rumensin Controlled Release Capsule (CRC) boluses when administered before calving to reduce disease and increase milk production. After accounting for disease incidences in a herd and the percentage by which Rumensin CRC can reduce them, and the increase in milk production attributable to administration of Rumensin CRC, the return on investment (ROI) per lactation was 4:1. Another partial budget model was developed to estimate the economic value of propylene glycol (PG) to treat ketosis when diagnosed by 3 different cow-side tests or when administered to all cows without using any cow-side testing. After accounting for the sensitivity and specificity of each test, ROI per lactation ranged from 2:1 to 4:1. The ROI was 2:1 when no cow-side testing was used. In conclusion, prevention of diseases that occur in the postpartum period and treatment of ketosis after calving yielded a positive ROI that varies based on disease incidence and method of diagnosis.

Valeur économique des ionophores et du propylèneglycol pour prévenir la maladie et traiter l'acétonémie au Canada. Un modèle de budget partiel a été développé pour évaluer la valeur économique des bolus de capsules à libération contrôlée (CLC) de Rumensin lors de l'administration avant le vêlage afin de réduire les maladies et d'accroître la production de lait. Après avoir tenu compte de l'incidence des maladies dans un troupeau et du pourcentage par lequel la CLC de Rumensin peut les réduire et de l'augmentation de la production de lait attribuable à l'administration de la CLC de Rumensin, le rendement du capital investi (RCI) par lactation était de 4:1. Un autre modèle de budget partiel a été développé pour estimer la valeur économique du propylèneglycol (PG) afin de traiter l'acétonémie lors du diagnostic par 3 tests différents pour les vaches ou lors de l'administration à toutes les vaches sans le recours à des tests auprès des vaches. Après avoir tenu compte de la sensibilité et de la spécificité de chaque test, le RCI par lactation s'échelonnait de 2:1 à 4:1. Le RCI était de 2:1 lorsqu'aucun test auprès des vaches n'était utilisé. En conclusion, la prévention des maladies qui se produit dans la période postpartum et le traitement de l'acétonémie après le vêlage a donné un RCI positif qui varie selon l'incidence de maladies et la méthode de diagnostic.(Traduit par Isabelle Vallières).

Antimicrobial dispensing by Ontario dairy veterinarians.

This questionnaire-based cross-sectional study was designed to capture the demographics of dairy practitioners in Ontario and to describe aspects of antimicrobial dispensing on-farm and over-the-counter by these veterinarians. The information collected revealed that the prescription status of a drug and the level of veterinary-client-patient relationship were important elements of dispensing policies. Over-the-counter dispensing records were incomplete, while only a small proportion of on-farm dispensing records contained pertinent information and directions as required by the Veterinarians Act. While respondents recognized that antimicrobial use in dairy herds could lead to resistance in cattle, few indicated that this was a significant public health issue. Veterinarians can play a key role in antimicrobial stewardship, part of which is the provision of complete written dispensing instructions to producers for antimicrobial use in dairy cattle.

La distribution des agents antimicrobiens par les vétérinaires qui s'occupent des vaches laitières en Ontario. Cette étude en coupe transversale a été réalisée à partir de réponses recueillies d'un questionnaire qui ciblait les données démographiques des praticiens des fermes laitières de l'Ontario en plus de décrire les habitudes de dispense des doses d'agents antimicrobiens in situ par les vétérinaires ou en vente libre auprès des distributeurs. Cette information nous a permis de reconnaître que le statut de l'agent antimicrobien prescrit et le niveau de relation entre le vétérinaire-client-patient sont des éléments très importants de la politique de dispense. Les données concernant les agents antimicrobiens achetés sans prescription étaient incomplètes dans les points de vente et seulement une petite proportion des données internes à la ferme contenait les informations et les dosages tels que requis par la loi sur les vétérinaires. Les répondants reconnaissaient que l'utilisation des agents antimicrobiens chez les vaches laitières pouvait élever leur résistance à ceux-ci, mais peu d'entre eux mentionnaient que ceci engendrait une réelle inquiétude pour la santé publique. Les vétérinaires ont donc un rôle clé à jouer et ils devront être assidus en fournissant, par écrit, des instructions complètes sur les prescriptions d'agents antimicrobiens aux producteurs de vaches laitières.(Traduit par les auteurs).

Erratum to "Risk factors for morbidity in 1- to 9-day-old dairy calves following caustic paste disbudding" (JDS Commun. 2:376-380).

[This corrects the article DOI: 10.3168/jdsc.2021-0121.].

Risk factors for morbidity in 1- to 9-day-old dairy calves following caustic paste disbudding.

Calfhood morbidity is an important issue on commercial dairy operations, with substantial production and welfare impacts. The objective of this observational study was to evaluate potential risk factors for morbidity, including disbudding, disbudding pain control, serum total protein (STP) concentrations, and haptoglobin concentrations in young dairy calves. A total of 140 heifer calves from a commercial dairy farm in southwestern Ontario, Canada, were enrolled at 1 to 9 d of age and followed for 1 wk. Calves were scored at enrollment for several health parameters using a scale from 0 to 3, with 0 representing normal and 3 representing severely abnormal. Calves were only included if they were considered healthy enough to participate using cut points of <3 for rectal temperature and fecal score; ≤2 for nasal discharge, ocular discharge, and cough score; and 1 for ear position, navel score, and joint score. To ensure that only calves that were considered healthy on the baseline day were included, 17 calves were excluded from analysis, resulting in a total of 123 calves. These calves were a part of a disbudding trial, with 100 disbudded using a commercial caustic paste and 23 sham disbudded with a placebo paste. The disbudding paste (commercial or sham) was applied to calves on enrollment day (baseline) with health scoring at baseline and 3 and 7 d later. The following health outcomes were analyzed: diarrhea (a fecal consistency score of ≥2), respiratory disease (a total respiratory score of ≥5), and general sickness [suffering from either diarrhea, respiratory disease, or a navel or joint infection (joint or navel score of ≥2)]. The following variables were assessed for association with the outcomes: STP, inadequate transfer of passive immunity (<5.2 g/dL STP), pain control treatment for disbudding (lidocaine nerve block alone, meloxicam alone, lidocaine nerve block and meloxicam, no pain control, sham), disbudding (disbudded or sham), and haptoglobin concentrations (taken on the baseline day, +3 d and +7 d). We did not detect any relationship between the development of a health outcome of interest (diarrhea, respiratory, or sick) and disbudding or pain control on any of the days following disbudding. However, for every 1 g/dL increase in STP concentration, calves had 0.24 and 0.33 times the odds of suffering from diarrhea or any sickness event, respectively, 3 d after disbudding. At 3 d after disbudding, for every 0.1 mg/mL increase in haptoglobin concentration on that day, calves had 1.34 and 1.20 times the odds of having diarrhea or a general sickness, respectively. These findings suggest that disbudding itself or the pain control method does not appear to influence health after the procedure when healthy calves are disbudded. Calves developing an illness 3 d after disbudding were more likely to have had lower STP concentrations and increased haptoglobin concentrations.

Relationships among milk urea-nitrogen, dietary parameters, and fecal nitrogen in commercial dairy herds.

Our study objective was to determine the ability of milk urea-nitrogen concentrations ([MUN]) to predict fecal nitrogen concentrations ([Fecal N]) in commercial dairy herds. A total of 83 dairy herds were each visited 3 times within 48 h after a monthly herd milk test. For each farm visit, forages were sampled for nutrient analyses, which were entered into a computerized ration evaluator, and fecal samples were taken per rectum from each of 6 cows (2 early-, 2 mid-, and 2 late-lactation). Fecal samples were pooled, mixed, and analyzed for nitrogen content. Fecal nitrogen concentrations were compared with the routinely measured nutritional parameters from the ration evaluation, and the herd average [MUN] for the previous milk test date using mixed linear regression analyses. Total protein supplied in the ration was significantly positively associated with [Fecal N], but herd average [MUN] was not associated (P > 0.10) with [Fecal N].

An investigation into the practices of dairy producers and veterinarians in dehorning dairy calves in Ontario.

The objective of this survey was to describe the current state of dehorning practices by dairy producers and veterinarians in Ontario and to identify opportunities to improve on existing practices. Two hundred and seven producers and 65 veterinarians completed a survey on dehorning practices during the summer of 2004. Seventy-eight percent of dairy producers dehorn their own calves; 22% use local anesthetics. Veterinarians dehorn calves for 31% of dairy clients; 92% use local anesthetics. Pain management was the most common reason for use of local anesthetics for both groups, while time (veterinarians) and time and cost (producers) were the most common reasons for lack of use. Producers who used local anesthetics were 6.5 times more likely to have veterinary involvement in their dehorning decisions. Thirteen percent of producers were unaware of the options for pain management. These results suggest that veterinarians should take the initiative to educate their clients about the options for pain management.

Efficacy of monensin sodium for the reduction of fecal shedding of Mycobacterium avium subsp. paratuberculosis in infected dairy cattle.

Reducing the quantity of Mycobacterium avium subsp. paratuberculosis (MAP) being shed by cows with Johne's disease should decrease the risk of spread of this disease to young stock. Previous work has suggested that monensin sodium decreases the pathologic lesions associated with Johne's disease, but the impact on shedding of viable MAP remains unknown. After serologic screening of 32 dairy herds in southwestern Ontario, 228 cows from 13 of these herds were enrolled into a randomized clinical trial. Fecal culture and PCR were used to identify 114 cows as potential fecal shedders, while another 114 cows were enrolled as ELISA negative, herd and parity matched controls. All cows were randomized to receive either a monensin controlled release capsule (CRC) or a placebo capsule. Serial fecal and blood samples were collected for fecal culture and serum ELISA testing over a 98-day period. On day 98 of the study, treatments were switched for all cows continuing in the trial. These remaining cows were followed for another 98 days with a similar sampling protocol. Mixed effect models were used to measure the impact of treatment on the number of colony forming units identified on fecal cultures over time. During the first 98 days of the study, cows treated with a monensin CRC were found to shed 3.4cfu per tube less than placebo treated cows (P=0.05). The serum ELISA S/P ratio was reduced by 1.39 units in cows given monensin (P=0.06). However, treatment with monensin did not reduce the odds of testing positive on serology. Only the cows shedding MAP on day 0 were found to have a reduced odds of testing positive on fecal culture when treated with monensin (OR=0.27; P=0.03). Monensin sodium administered to infected animals at 335mg/day marginally reduced fecal shedding of MAP in mature dairy cattle, but the biological significance of this reduction is unknown.

Monensin might protect Ontario, Canada dairy cows from paratuberculosis milk-ELISA positivity.

Our objective was to define the role of monensin sodium in protecting cows from being milk-ELISA positive for paratuberculosis in Ontario, Canada dairy herds. In total, 4933 dairy cows from 94 herds were enrolled in this cross-sectional study. Forty-four of the enrolled herds were selected purposively by their herd veterinarian and another 50 herds were randomly selected from a local milk production-recording agency. A herd-management survey was completed on each farm during the months of May through August 2003. During this same time-period, composite milk samples were collected from all lactating cows and tested with a milk-ELISA for antibodies to Mycobacterium avium subspecies paratuberculosis. Analyses were stratified according to the paratuberculosis history of the herds. In the 48 herds in which paratuberculosis had not been diagnosed before, the use of calf hutches and monensin in milking cows were both associated with reduced odds of a cow testing positive (OR=0.19 and 0.21, respectively). In the 46 herds with a prior history of paratuberculosis, feeding monensin to the breeding-age heifers was associated with decreased odds of a cow testing positive (OR=0.54). Monensin use might be associated with milk-ELISA positivity, but its impact on the transmission of paratuberculosis remains unknown.