The welfare of ill and injured feedlot cattle: a review of the literature and implications for managing feedlot hospital and chronic pens.

By definition, ill and injured animals are on the negative valence of animal welfare. For beef cattle kept in feedlot settings, advances in cattle health management have resulted in a greater understanding and prevention of illness and injury. However, the management of cattle once they become ill and injured is an understudied area, and there are gaps in knowledge that could inform evidence-based decision-making and strengthen welfare for this population. The aim of this review is to provide a comprehensive overview of the acquired knowledge regarding ill and injured feedlot cattle welfare, focusing on existing knowledge gaps and implications for hospital and chronic pen management and welfare assurance. Ill and injured feedlot cattle consist of acutely impaired animals with short-term health conditions that resolve with treatment and chronically impaired animals with long-term health conditions that may be difficult to treat. A literature search identified 110 articles that mentioned welfare and ill and injured feedlot cattle, but the population of interest in most of these articles was healthy cattle, not ill and injured cattle. Articles about managing ill and injured cattle in specialized hospital (n = 12) or chronic (n = 2) pens were even more sparse. Results from this literature search will be used to outline the understanding of acutely and chronically ill and injured feedlot cattle, including common dispositions and welfare considerations, behavior during convalescence, and strategies for identifying and managing ill and injured cattle. Finally, by working through specific ailments common in commercial feedlot environments, we illustrate how the Five Domains Model can be used to explore feelings and experiences and subsequent welfare state of individual ill or injured feedlot cattle. Using this approach and our knowledge of current industry practices, we identify relevant animal-based outcomes and critical research questions to strengthen knowledge in this area. A better understanding of this overlooked topic will inform future research and the development of evidence-based guidelines to help producers care for this vulnerable population.

Secure Sheep and Wool Supply Plan for Continuity of Business.

Sheep operations will be subject to movement controls during a US foot and mouth disease outbreak and should be prepared to manage animal and product movement disruptions. The voluntary Secure Sheep and Wool Supply (SSWS) Plan for Continuity of Business provides tools for the sheep industry to develop contingency plans, write enhanced, operation-specific biosecurity plans, and learn about disease surveillance opportunities and challenges. The SSWS Plan is science-based and risk-based, funded by the American Sheep Industry Association, and developed collaboratively with industry, government officials, and veterinarians at Iowa State University. For more information, visit www.securesheepwool.org.

Validation of a portable pneumatic captive bolt device as a one-step method of euthanasia for use in depopulation of feedlot cattle.

OBJECTIVE: To validate the effectiveness of a penetrating captive bolt device with a built-in low-pressure air channel pithing mechanism (PCBD) as a 1-step method for euthanasia of cattle. DESIGN: Clinical trial. ANIMALS: 66 feedlot steers and heifers (weight, 227 to 500 kg [500 to 1,100 lb]) that were not expected to survive or finish the feeding period with their cohorts. PROCEDURES: Cattle were transported to a university facility and euthanized with the PCBD. For each calf, clinical variables were monitored and recorded immediately before and for at least 10 minutes after application of the PCBD. Following euthanasia, the head of each calf was removed and trauma to the brain and skull was assessed and scored. RESULTS: Death was successfully achieved with the PCBD without application of an ancillary technique in all 66 cattle; however, 4 (6%) cattle required a second or third shot from the PCBD because of technical errors in its placement. All shots from the PCBD that entered the cranial vault successfully rendered cattle unconscious without a return to sensibility. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that the PCBD was an effective 1-step method of euthanasia for use in mass depopulation of feedlot cattle.

Pain and sickness behavior associated with corneal lesions in dairy calves.

Infectious bovine keratoconjunctivitis (IBK) is a common corneal disease of calves that adversely affects animal welfare by causing pain and weight loss. Identifying behavioral indicators of pain and sickness in calves with IBK is necessary for designing studies that aim to identify effective means of pain mitigation. Consistent with principles of the 3Rs for animal use in research, data from a randomized blinded challenge study was used to identify and describe variation of behaviors that could serve as reliable indicators of pain and sickness in calves with corneal injuries. Behavioral observations were collected from 29 Holstein calves 8 to 12 weeks of age randomly allocated to one of three treatments: (1) corneal scarification only, (2) corneal scarification with inoculation with Moraxella bovoculi and (3) corneal scarification with inoculation with Moraxella bovis. Behavior was continuously observed between time 1230 - 1730 h on day -1 (baseline time period) and day 0 (scarification time period). Corneal scarification and inoculation occurred between 0800 - 1000 h on day 0. Frequency of head-directed behaviors (head shaking, head rubbing, head scratching) and durations of head rubbing, feeding, standing with head lifted, lying with head lifted and sleeping were compared between study days and groups. Following scarification, the frequency of head-directed behavior significantly increased (p = 0.0001), as did duration of head rubbing (p=0.02). There was no significant effect of trial, trial day, treatment or treatment-day interaction on other behaviors studied. Our study demonstrated that head-directed behavior, such as head shaking, rubbing and scratching, was associated with scarification of eyes using an IBK challenge model, but sickness behavior was not observed.

Schirmer tear test I and rebound tonometry findings in healthy calves.

OBJECTIVE: To describe Schirmer tear test I and rebound tonometry findings in healthy bovine calves. ANIMALS STUDIED: Thirty-three clinically normal dairy breed calves of mean (SD) 11 (1.1) weeks (range, 9.3-13.3 weeks) of age were evaluated. PROCEDURES: A Schirmer tear test I was performed on each eye followed by tonometry, using a TonoVet(®) without topical anesthesia. We report means (SD) and statistical analysis of data for each assay. RESULTS: For both Schirmer tear test (STT) I and tonometry, significant differences were not found between fellow eyes (P = 0.1536 and P = 0.83, respectively). The mean (SD) STT I value of all eyes was 20.4 (5.0) mm/min (range, 9-34 mm/min) while the mean (SD) intraocular pressure (IOP) value of all eyes was 15.2 (5.2) mmHg (range, 7-25 mmHg). CONCLUSIONS: This study reports normal data for the STT I and rebound tonometry in calves. This data may be useful in complete ophthalmic examinations of cattle, guiding diagnosis of glaucoma, uveitis, and keratoconjunctivitis sicca. However, results of these diagnostic modalities must be interpreted in light of clinical signs, given the wide range of normal values obtained in this study.

Serum concentrations of haptoglobin and haptoglobin-matrix metalloproteinase 9 (Hp-MMP 9) complexes of bovine calves in a bacterial respiratory challenge model.

BACKGROUND: Serum haptoglobin (Hp) and haptoglobin matrix metalloproteinase 9 complexes (Hp-MMP 9) have been identified as biomarkers with diagnostic potential in cattle with conditions resulting in an acute inflammatory response. The purpose of this study was to evaluate potential diagnostic applications of serum Hp and Hp-MMP 9 concentrations in calves with BRD and establish a timeline for their detection in calves experimentally challenged with Bibersteinia trehalosi and Mannheimia haemolytica. Thirty-five cross bred dairy calves were inoculated via tracheal catheterization with either a PCR confirmed leukotoxin negative B. trehalosi isolate, a PCR confirmed leukotoxin positive B. trehalosi isolate, a Mannheimia haemolytica isolate, a combination of leukotoxin negative B. trehalosi and M. haemolytica, or a negative control. Serum samples were collected throughout the study. Calves were euthanized and necropsy performed on day 10 post inoculation. RESULTS: M. haemolytica inoculated calves had increased lung involvement. Serum Hp and Hp- MMP 9 concentrations were elevated compared to the other treatment groups. Increases in serum Hp and Hp-MMP 9 concentrations for the M. haemolytica group were significantly different from other study groups on day 7 of the study. B. trehalosi inoculated calves did not have increased lung involvement compared to control calves, but the leukotoxin positive B. trehalosi group demonstrated increased serum Hp-MMP 9 concentrations from day 3 to the end of the study compared to the pre-inoculation concentrations. CONCLUSION: Serum Hp-MMP 9 concentration is a useful diagnostic tool for detecting early pulmonary inflammation in calves challenged with B. trehalosi and M. haemolytica. Serum Hp-MMP 9 may also be a useful tool in detecting subclinical pulmonary inflammation in challenged calves.

Randomized clinical trial to evaluate the pathogenicity of Bibersteinia trehalosi in respiratory disease among calves.

BACKGROUND: Bibersteinia trehalosi causes respiratory disease in ruminants particularly in wild and domestic sheep. Recently, there has been an increased number of B. trehalosi isolates obtained from diagnostic samples from bovine respiratory disease cases. This study evaluated the role of B. trehalosi in bovine respiratory disease using an intra-tracheal inoculation model in calves. Thirty six cross bred 2-3 month old dairy calves were inoculated intra-tracheally with either leukotoxin negative B. trehalosi, leukotoxin positive B. trehalosi isolate, Mannheimia haemolytica, a combination of leukotoxin negative B. trehalosi and M. haemolytica or negative control. Calves were euthanized and necropsy performed on day 10 of study. RESULTS: B. trehalosi inoculated calves did not have increased lung involvement compared to control calves. Additionally, B. trehalosi was only cultured once from the lungs of inoculated calves at necropsy. CONCLUSIONS: Based on these findings B. trehalosi may not be a primary pathogen of respiratory disease in cattle. Culture of B. trehalosi from diagnostic submissions should not be immediately identified as a primary cause of respiratory disease.

Corneal sensitivity in healthy bovine calves.

OBJECTIVE: To evaluate corneal sensitivity as measured by the corneal touch threshold in healthy bovine calves. ANIMALS STUDIED: Twelve clinically normal male calves with predominantly Holstein genetics and a median age of 76.5 days (range, 67-92 days). PROCEDURES: Corneal touch threshold (CTT) of the central cornea was measured in both eyes of each calf using a Cochet-Bonnet aesthesiometer. RESULTS: The mean ± standard deviation corneal touch threshold of all eyes was 1.33 ± 1.1 g/mm(2) (range, 0.62-66.15 g/mm(2) ), corresponding to a filament length of 34.56 ± 8.02 mm (range, 14-47.5 mm). There was no significant difference between fellow eyes. CONCLUSIONS: Cochet-Bonnet aesthesiometry was well tolerated in all 12 calves using a modified head restraint. Calves in this study may have a relatively sensitive central cornea compared to adult cattle and some other species; however, wide variation among individuals and eyes may be possible. Studies utilizing larger calf populations are necessary to establish reference ranges.

A survey of reasons why veterinarians enter rural veterinary practice in the United States.

OBJECTIVE: To identify factors associated with interest in or choosing a career in rural veterinary practice (RVP). DESIGN: Cross-sectional descriptive study. SAMPLE POPULATION: Veterinarians and veterinary students in the United States. PROCEDURES: Veterinary students and veterinarians in any area of practice were solicited to participate in an online survey through invitation letters sent to various veterinary associations. Proportions of respondents assigning high importance to various factors were analyzed for differences among gender, age, and background groups. RESULTS: 1,216 responses were received. In general, survey respondents indicated that RVP could be characterized as the practice of veterinary medicine in any community where agriculture represented a significant part of the local economy. Responses also indicated that RVP should not be confused with large animal or food animal exclusive practice. Most respondents (38.9%) developed an interest in RVP early in life (before 8th grade), with 13.0% reportedly developing their interest in RVP during veterinary school. The most highly ranked factors with regard to influence on developing an interest in RVP were having relatives with a farm background, having a veterinarian in RVP as a mentor, and exposure to RVP during veterinary school. Gender, generational category, background (rural vs urban), and livestock experience were significantly associated with when respondents developed an interest in RVP and with factors important in developing that interest. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study suggested that various factors are associated with interest in and choosing a career in RVP. These factors should be considered when strategies for increasing interest and encouraging careers in RVP are planned.

A survey of reasons why veterinarians leave rural veterinary practice in the United States.

OBJECTIVE: To identify factors associated with veterinarians leaving a career in rural veterinary practice (RVP). DESIGN: Cross-sectional descriptive study. SAMPLE POPULATION: Veterinarians from the United States who no longer worked in RVP. PROCEDURES: Veterinarians in any area of practice were solicited to participate in an online survey through invitation letters sent to various veterinary associations. Those who indicated that they had left RVP were asked to rank the importance of various potential factors in their decision to leave RVP. RESULTS: 805 responses were obtained from veterinarians who had worked in RVP, of which 246 (30.6%) had left RVP. Most (231/246 [93.9%]) of those who reported leaving RVP had been in practice > 5 years, and 75.2% (185/246) had been in practice > 12 years. Eighty-three (33.7%) who left RVP pursued careers in urban areas, 72 (29.3%) entered academia, and 7 (2.8%) retired. Reasons for leaving RVP ranked by the highest proportions of respondents as being of high importance were emergency duty, time off, salary, practice atmosphere, and family concerns. Women ranked factors such as time off, mentorship, practice atmosphere, conflict with staff, and gender issues as being of high importance more often than men did. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the perceived shortage of veterinarians in RVP may be in part influenced by a lack of retention, particularly among experienced veterinarians. Targeted efforts to tackle issues related to emergency duty, time off, salary, practice atmosphere, and family issues could help alleviate the efflux from RVP.

Association of neonatal serum immunoglobulin G1 concentration with health and performance in beef calves.

OBJECTIVE: To evaluate associations between neonatal serum IgG1 concentration and pre- and postweaning morbidity and mortality rates and average daily gains (ADGs) in beef calves and define a cutoff point for serum IgG1 concentration necessary for optimal health and performance of beef calves. DESIGN: Nonconcurrent cohort study. ANIMALS: 1,568 crossbred beef calves. PROCEDURE: Single radial immunodiffusion was used to quantitate IgG1 concentration in sera collected from calves between 24 and 72 hours after birth. Logistic regression, ANCOVA, and likelihood ratios were used to analyze data. RESULTS: In the preweaning period, lower perinatal IgG1 concentrations were significantly associated with higher morbidity rates, higher mortality rates, and lower ADGs. Calves with serum IgG1 concentration < 2,400 mg/dL were 1.6 times as likely to become ill before weaning and 2.7 times as likely to die before weaning as calves with higher serum IgG1 concentrations. Calves with serum IgG1 concentration of at least 2,700 mg/dL weighed an estimated 3.35 kg (7.38 lb) more at 205 days of age than calves with lower serum IgG1 concentration. No significant association of serum IgG1 concentration with feedlot morbidity, death, or ADG was identified. CONCLUSIONS AND CLINICAL RELEVANCE: By use of likelihood ratios, the threshold of serum IgG1 concentration for optimal health and performance of calves was higher than values reported previously. Implementation and maintenance of management and intervention strategies designed for early detection and treatment of calves at risk for failure of passive transfer will likely result in increases in preweaning health and performance parameters.

Immunologic responses to West Nile virus in vaccinated and clinically affected horses.

OBJECTIVE: To compare neutralizing antibody response between horses vaccinated against West Nile virus (WNV) and horses that survived naturally occurring infection. DESIGN: Cross-sectional observational study. ANIMALS: 187 horses vaccinated with a killed WNV vaccine and 37 horses with confirmed clinical WNV infection. PROCEDURE: Serum was collected from vaccinated horses prior to and 4 to 6 weeks after completion of an initial vaccination series (2 doses) and 5 to 7 months later. Serum was collected from affected horses 4 to 6 weeks after laboratory diagnosis of infection and 5 to 7 months after the first sample was obtained. The IgM capture ELISA, plaque reduction neutralization test (PRNT), and microtiter virus neutralization test were used. RESULTS: All affected horses had PRNT titers > or = 1:100 at 4 to 6 weeks after onset of disease, and 90% (18/20) maintained this titer for 5 to 7 months. After the second vaccination, 67% of vaccinated horses had PRNT titers > or = 1:100 and 14% had titers < 1:10. Five to 7 months later, 33% (28/84) of vaccinated horses had PRNT titers > or = 1:100, whereas 29% (24/84) had titers < 1:10. Vaccinated and clinically affected horses' end point titers had decreased by 5 to 7 months after vaccination. CONCLUSIONS AND CLINICAL RELEVANCE: A portion of horses vaccinated against WNV may respond poorly. Vaccination every 6 months may be indicated in certain horses and in areas of high vector activity. Other preventative methods such as mosquito control are warranted to prevent WNV infection in horses.