Half-life of serum anti-Müllerian hormone and changes after gonadectomy in adult female and male dogs with normal and abnormal gonads

Anti-Müllerian hormone (AMH) is a biomarker for the presence of gonadal tissue. Changes in serum AMH after gonadectomy are not well established, and its serum half-life is unknown in dogs. We measured serum AMH with a validated electro-chemiluminescent immunoassay in adult female (n = 12) and male (n = 7) dogs with normal gonads, as well as in dogs with gonadal pathology (ovarian remnant syndrome, ORS n = 3, testicular tumor [Leydig cell, Sertoli cell, seminoma] n = 3, unilateral abdominal cryptorchid n = 4) on the day of gonadectomy (D0), and on D3, D7, D14 (females and males), and D21, D28 (males only). Males had higher AMH concentrations than females independent of gonadal status (P < 0.001). Dogs with ORS had lower initial AMH (0.45 ± 0.43 ng/ml) than bitches with normal gonads (1.16 ± 0.44 ng/ml; P = 0.027). Cryptorchid dogs had higher initial concentrations (80.57 ± 52.81 ng/ml) than males with normal gonads (7.92 ± 2.45 ng/ml; P = 0.004), and those with testicular tumors (18.63 ± 5.04 ng/ml) were intermediate (P ≥ 0.250). AMH decreased over time (P ≤ 0.012) and was 0.01-0.04 ng/ml by D14 in females and 0.02-0.12 ng/ml by D28 in males. Serum half-life in the whole study population was 2.85 ± 0.51 days and did not differ between groups. In conclusion, serum AMH can differentiate between intact and gonadectomized status of adult dogs by 14 days after ovario(hyster)ectomy in females and by 28 days after surgical castration in males.

Identifying the target population and preventive strategies to combat feline obesity

Feline obesity continues to be a priority health and welfare issue. Most research surrounding obesity currently focuses on obesity treatment. However, treatment for feline obesity is slow, often unsuccessful and not without consequences. Identifying high-risk populations for obesity onset is crucial for developing and implementing preventive strategies. This review identifies post-gonadectomy kittens aged 5-12 months as the primary target population for obesity prevention in domestic cats and highlights dietary and feeding management strategies to be implemented for obesity prevention.

To castrate or not to castrate? That is the question…

There is growing evidence that surgical castration of dogs may not bring all the benefits previously assumed. Times have changed too, and vets and clients are increasingly questioning whether routine castration should continue to be considered best practice.

Behavioural issues: castration may not be the solution

Removing the source of reproductive hormones may not be a panacea for unwelcome or unwanted behaviours - in fact, it may compound them.

The effect of immunocastration of male and female Duroc pigs on the morphological, mechanical and compositional characteristics of pork belly

Pork belly is an important and heterogeneous cut, characterized by its fat content. Immunocastration is an alternative to surgical castration that can modify the composition of carcasses and cuts and it can affect at its processing. This work compares the morphological, mechanical and compositional characteristics of pork belly of (1) pure Duroc pigs from surgically castrated males (CM), entire females (EF) and immunocastrated females (IF), and (2) Duroc crossbreed pigs from immunocastrated males (IM) and entire males (EM). Two trials were carried out: Trial 1, in which 36 bellies were evaluated, 12 from each sexual type, CM, EF and IF; and Trial 2, where 30 bellies were used, 15 from each sexual type, IM and EM. Results show few differences in bellies from EF and IF, while those from CM were fatter and firmer and with lower polyunsaturated fat. Bellies from IM were longer and firmer than those from EM, and their skin was thinner. IM bellies had higher saturated and lower polyunsaturated fat than those from EM. To conclude, the sex of the pigs affects belly characteristics and this could be a criterion for determining the destination of the bellies in the cutting plant. Immunocastration of pure Duroc females had a lower effect on the belly characteristics when compared to those from entire females, but some differences could be found in the fat distribution. Immunocastration of Duroc crossbred males produces firmer and thicker bellies, with a thinner skin, that could be advantageous for slicing and further processing.

Effect of gonadectomy on pain assessment in dogs undergoing orthopaedic stifle surgery

OBJECTIVE

To compare pain perception between gonadectomized and intact dogs.

STUDY DESIGN

Blinded, prospective, cohort study.

ANIMALS

A group of 74 client-owned dogs.

METHODS

Dogs were divided into four groups: group 1-female/neutered (F/N), group 2-female/intact (F/I), group 3-male/neutered (M/N) and group 4-male/intact (M/I). Premedication consisted of intramuscularly administered acepromazine (0.05 mg kg-1) and morphine (0.2 mg kg-1), and subcutaneously administered carprofen (4 mg kg-1). Anaesthesia was induced with propofol (1 mg kg-1 intravenously and supplementary doses to effect) and maintained with isoflurane in 100% oxygen. Intraoperative analgesia was achieved with fentanyl infusion (0.1 μg kg-1 minute-1). Pain assessments [using the University of Melbourne Pain Scale (UMPS) and an algometer at the incision site (IS), parallel to the incision site (NIS), and on the contralateral healthy limb] were performed preoperatively, and at 1, 2, 4, 6, 9 and 20 hours after extubation. The time-standardised area under the curve (AUCst) for measurements was calculated and compared by performing a one-way multivariate analysis of variance (manova). Statistical significance was set at p < 0.05.

RESULTS

Postoperatively, F/N exhibited higher pain than F/I, with estimated marginal means (95% confidence intervals) AUCstISGroup1 909 (672-1146) versus AUCstISGroup2 1385 (1094-1675) (p = 0.014), AUCstNISGroup1 1122 (823-1420) versus AUCstNISGroup2 1668 (1302-2033) (p = 0.024) and AUCstUMPSGroup1 5.30 (4.58-6.02) versus AUCstUMPSGroup2 4.1 (3.2-5.0) (p = 0.041). Similarly, M/N showed higher pain than M/I with AUCstISGroup3 686 (384-987) versus AUCstISGroup4 1107 (871-1345) (p = 0.031) and AUCstNISGroup3 856 (476-1235) versus AUCstNISGroup4 1407 (1109-1706) (p = 0.026), and AUCstUMPSGroup3 6.0 (5.1-6.9) versus AUCstUMPSGroup4 4.4 (3.7-5.2) (p = 0.008).

CONCLUSIONS AND CLINICAL RELEVANCE

Gonadectomy affects pain sensitivity in dogs undergoing stifle surgery. Neutering status should be taken into consideration when planning individualized anaesthetic/analgesic protocols.

Age at gonadectomy, sex, and breed size affect risk of canine overweight and obese outcomes: a retrospective cohort study using data from United States primary care veterinary clinics

OBJECTIVE

To examine the risk of developing an overweight or obese (O/O) body condition score (BCS) in gonadectomized versus intact dogs and, separately, the impact of age at gonadectomy on O/O outcomes among sterilized dogs.

ANIMALS

Dogs were patients of Banfield Pet Hospital in the US from 2013 to 2019. After exclusion criteria were applied, the final sample consisted of 155,199 dogs.

PROCEDURES

In this retrospective cohort study, Cox proportional hazards models evaluated associations between O/O and gonadectomy status, sex, age at gonadectomy, and breed size. Models were used to estimate the risk of becoming O/O in gonadectomized versus intact dogs and, separately, to estimate risk of O/O BCS according to age at surgery among gonadectomized dogs.

RESULTS

Gonadectomy increased O/O risk for most dogs compared to intact dogs. Unlike most prior findings, O/O hazard ratios among gonadectomized versus intact dogs were larger for males than females. O/O risk varied according to breed size but not linearly. Sterilizing at 1 year old tended to yield a lower O/O risk compared to doing so later. Comparative O/O risk among dogs gonadectomized at 6 months versus 1 year varied by breed size. Overall patterns for obesity related to size were similar to patterns in the O/O analysis.

CLINICAL RELEVANCE

Veterinarians are uniquely positioned to help prevent O/O in their patients. Results extend understanding of risk factors for O/O development in dogs. In combination with information about other benefits and risks associated with gonadectomy, these data can help tailor recommendations regarding gonadectomy in individual dogs.

Evaluation of a brief video intervention aimed at UK-based veterinary surgeons to encourage neutering cats at four months old: A randomised controlled trial

In the UK, it is currently recommended that owned cats be neutered from four months of age. However, its uptake is inconsistent across the veterinary profession. Here we assess the effect of a brief video intervention that aimed to encourage four month neutering, whilst preserving clinical autonomy. We compare this theory-driven approach with traditional information giving and a control group. Veterinary surgeons who regularly undertook feline neutering work in the UK but did not routinely neuter cats at four months and/or recommend four month neutering for client owned cats were randomised into three groups (n = 234). Participants received either no information, a written summary of evidence or the video. The primary behaviour outcomes were the recommending and carrying out of neutering cats at four months. Evaluative, belief and stages of change measures were also collected. Self-reported outcomes were assessed pre-intervention, immediately post-intervention, two months post-intervention and six months post-intervention. At two months, participants that had received the video intervention were significantly more likely to have started recommending neutering cats at four months. At six months, participants that had received the video intervention were significantly more likely to have started carrying out neutering cats at four months. There were no significant behaviour changes for the other groups. At two months, the video intervention was associated with a significant increase in thinking about, and speaking to colleagues about, four-month neutering, relative to the control group. The written summary of evidence had no similar effect on stages of change, despite it being perceived as a significantly more helpful resource relative to the video. To conclude, a brief one-off video intervention resulted in an increase in positive behaviours towards neutering cats at 4 months, likely mediated by the social influences of the intervention prompting the opportunity to reflect and discuss four-month neutering with colleagues.

Serum C-reactive protein and iron levels following gonadectomy are not modified by perioperative administration of robenacoxib to dogs

The aim of this study was to evaluate the perioperative effects of robenacoxib on serum C-reactive protein (CRP) and iron concentrations in dogs undergoing gonadectomy. In a prospective, blinded, controlled clinical trial, 60 healthy dogs were randomly assigned to receive preoperative subcutaneous injection of either robenacoxib [2 mg/kg body weight (BW)], meloxicam (0.2 mg/kg BW), or saline (0.04 mL/kg BW), followed by oral administration over 72 h (robenacoxib: 2 to 4 mg/kg BW; meloxicam: 0.1 mg/kg BW; saline: gelatin capsules). Blood samples were taken before surgery and 12, 24, 48, 72 h, and 7 d after surgery. Pain scores were assessed via the short-form Glasgow Composite Pain Scale over 72 h postoperatively. C-reactive protein (CRP) and iron serum levels increased and decreased (P < 0.01, both), respectively, after surgery and returned to baseline within 1 wk. No differences were observed among treatments (P > 0.05) or based on surgery/gender (P > 0.05). Pain assessment revealed a higher incidence of treatment failure in saline (6 females versus 2 and 1 female in robenacoxib and meloxicam, respectively). In conclusion, robenacoxib and meloxicam had no influence on postoperative CRP or iron in dogs, which suggests that these nonsteroidal anti-inflammatory drugs (NSAIDs) do not have a relevant effect on these biomarkers.

Laparoscopic gonadectomy in a dog with 78,XX/78,XY chimerism and underdeveloped reproductive organs

CASE DESCRIPTION

A 1-year-old externally sexually intact female Great Dane was referred for further evaluation of abnormal and underdeveloped internal reproductive organs.

CLINICAL FINDINGS

Physical examination findings included a cranioventrally displaced vulva and a grade 2/6 left apical systolic heart murmur. No uterus or ovaries were identified during abdominal ultrasonography. Computed tomography with retrograde vaginourethrography revealed an underdeveloped uterus and possible left intra-abdominal gonad. Karyotyping revealed mixed sex chromosomes (70% XY and 30% XX). Analysis of a serum sample yielded positive results for anti-Müllerian hormone; other findings included mid range estradiol concentration (48.2 pg/mL [within reference intervals for sexually intact and neutered males and females]), low progesterone concentration (< 0.2 ng/mL [within reference intervals for anestrous females]), and low testosterone concentration (< 20 ng/dL [similar to the expected concentration in neutered males]). Overall, the results of the sex hormone analyses were consistent with findings for either a sexually intact female or a neutered male dog. The dog's cardiac structure and function were echocardiographically normal.

TREATMENT AND OUTCOME

The dog was anesthetized and underwent laparoscopic gonadectomy. The gonads, although abnormal and underdeveloped, were readily identified intraoperatively and successfully removed. On the basis of histologic findings, the removed gonads were confirmed to be rudimentary testicles. The dog recovered from anesthesia and surgery without complications.

CLINICAL RELEVANCE

Laparoscopic surgery was effective for visualization of abnormal and hypoplastic reproductive organs when abdominal ultrasonography and CT were of limited diagnostic usefulness, and laparoscopic surgery allowed straightforward gonadectomy in a 78,XX/78,XY chimeric dog.

Adipose Tissue Gene Expression of Entire Male, Immunocastrated and Surgically Castrated Pigs

Differences in adipose tissue deposition and properties between pig male sex categories, i.e., entire males (EM), immunocastrates (IC) and surgical castrates (SC) are relatively well-characterized, whereas the underlying molecular mechanisms are still not fully understood. To gain knowledge about the genetic regulation of the differences in adipose tissue deposition, two different approaches were used: RNA-sequencing and candidate gene expression by quantitative PCR. A total of 83 differentially expressed genes were identified between EM and IC, 15 between IC and SC and 48 between EM and SC by RNA-sequencing of the subcutaneous adipose tissue. Comparing EM with IC or SC, upregulated genes related to extracellular matrix dynamics and adipogenesis, and downregulated genes involved in the control of lipid and carbohydrate metabolism were detected. Differential gene expression generally indicated high similarity between IC and SC as opposed to EM, except for several heat shock protein genes that were upregulated in EM and IC compared with SC. The candidate gene expression approach showed that genes involved in lipogenesis were downregulated in EM compared with IC pigs, further confirming RNA-sequencing results.

Contrasting practices and opinions of UK-based veterinary surgeons around neutering cats at four months old

BACKGROUND

Many cats in the UK are not neutered before reaching potential breeding age. The purpose of this investigation was to understand the prevalence of veterinarians' behaviours around neutering cats at four months of age and to identify any needs of the veterinary profession on this.

METHODS

A sample of 483 veterinarians that completed a cross-sectional online questionnaire were included in quantitative and qualitative analyses.

RESULTS

Almost 70 per cent of veterinarians indicated they were comfortable carrying out neutering on cats of four months of age, and approximately half of veterinarians indicated they would recommend neutering client-owned cats at four months of age if practice policy permitted. There was no association found between these practices and geographic risk factors. Instead, neutering at four months was associated with the gender of the veterinarian, their practice policy and whether they routinely neuter unowned cats. Veterinarians have contrasting beliefs on similar themes, depending on whether they neuter kittens at four months or not, including differing opinions on general anaesthetic, surgery risks, owner compliance and their perceptions of neutering practices within the wider profession.

CONCLUSION

Familiarity and experience with the procedure, alongside perceived norms, are central to beliefs. We also highlight informational and learning barriers.

Local anesthesia in piglets undergoing castration-A comparative study to investigate the analgesic effects of four local anesthetics on the basis of acute physiological responses and limb movements

Surgical castration of male piglets without analgesia is a painful procedure. This prospective, randomized and double-blinded study aimed to evaluate the analgesic effects of four different local anesthetics for piglet castration during the first week of life. In total, 54 piglets aged 3 to 7 days were distributed into 6 treatment groups: handling (H); castration without pain relief (sodium chloride, NaCl); and castration with a local anesthetic: 4% procaine (P), 2% lidocaine (L), 0.5% bupivacaine (B) or 20 mg/ml mepivacaine (M). By excluding stress and fear as disruptive factors via a minimum anesthesia model, all piglets received individual minimum alveolar concentration (MAC) isoflurane anesthesia. Twenty minutes before castration, all treatment groups except group H received one injection per testis. Then, 0.5 ml of a local anesthetic or NaCl was injected intratesticularly (i.t.), and 0.5 ml was administered subscrotally. Acute physiological responses to noxious stimuli at injection and castration were evaluated by measuring blood pressure (BP), heart rate (HR), cortisol, epinephrine, norepinephrine and chromogranin A (CgA); limb movements were quantified. The results confirm that castration without analgesia is highly painful. Surgical castration without pain relief revealed significant changes in mean arterial blood pressure (MAP) and HR. Local anesthetic administration significantly reduced changes in BP and HR associated with castration. Piglets receiving a preoperative local anesthetic exhibited the fewest limb movements during castration, while the NaCl group exhibited the most. Injection itself was not associated with significant changes in MAP or HR. However, many piglets exhibited limb movements during injection, indicating that the injection itself causes nociceptive pain. No significant differences were found between groups regarding parameters of plasma cortisol, catecholamines and CgA. In conclusion, all four local anesthetics administered are highly effective at reducing signs of nociception during castration under light isoflurane anesthesia. However, injection of a local anesthetic seems to be painful.

Computed tomographic features of the prostatic gland in neutered and intact dogs

BACKGROUND

Aim was to investigate age-dependent changes in the prostate of castrated dogs in computed tomographic (CT) examination. Thirty-six canine prostates were evaluated in pre- and post-contrast CT scans. Dogs were divided in groups with homogenous prostatic tissue (25/36) and with tissue alterations (11/36). Prostatic attenuation in Hounsfield Units (HU) and prostatic size were measured and a ratio of the prostatic size to the sixth lumbar vertebra was calculated. Additionally, the CT images of the prostate were compared with ultrasound examination.

RESULTS

In pre-contrast CT scans no significant differences were found in prostatic size between homogenous and altered prostatic tissue groups whereas prostatic attenuation differed significantly in post-contrast CT between these groups. The homogenous tissue pattern of homogeneous prostates could be confirmed in CT images and in ultrasound examination. Concerning prostates with alterations, the results differed between ultrasound and CT examination in four cases of 11 dogs with tissue alterations.

CONCLUSIONS

CT is beneficial to examine the prostate of castrated dogs. The prostatic attenuation is characteristic for the prostatic morphology, which can vary due to ageing processes. Differences in attenuation and size can be found between prostates of castrated and intact dogs. Using contrast agent, CT can visualize prostatic alterations, which were not seen in ultrasound. The presented results should be considered preliminary until a study with larger sample size and histologic examination of the prostates is performed.

Age at gonadectomy and risk of overweight/obesity and orthopedic injury in a cohort of Golden Retrievers

INTRODUCTION

In the United States, gonadectomy is common and widely promoted as a component of responsible pet ownership. The recent publication of several studies examining the effect of gonadectomy on future health has challenged long-held assumptions and recommendations for gonadectomy in companion animals. The purpose of this study was to characterize the associations between gonadectomy and two outcomes: overweight/obesity and orthopedic injuries, in a large prospective study of Golden Retrievers.

METHODS

Age at gonadectomy was divided into four categories: intact (reference), ≤ 6 months, > 6 months ‒ ≤ 12 months, and > 12 months. Dogs with a Purina Body Condition Score of 7 or greater were classified as overweight or obese. Orthopedic injuries considered were the first instance of veterinary-reported cranial cruciate ligament injury and clinically evident osteoarthritis. We performed survival analyses on a cohort of Golden Retrievers to estimate the associations of interest using proportional hazards. We adjusted for age at study enrollment, owner-reported activity level, and dog's sex.

RESULTS

Compared to intact dogs, all gonadectomy age categories showed increased risk for the development of overweight/obesity. (≤ 6 months, HR: 1.81, 95% CI: 1.36-2.40), p-value: <0.0001; 6 months to ≤ 12 months, HR: 2.21, 95% CI: 1.77-2.73, p-value: < 0.0001; > 12 months, HR: 1.56, 95% CI: 1.24-1.96, p-value: 0.0001). Compared to intact dogs, dogs who were ≤ 6 months at gonadectomy had increased risk for orthopedic injury (HR: 4.06, 95% CI: 2.15-7.67, p-value: <0.00001).

DISCUSSION

This study presents prospectively acquired data demonstrating that gonadectomy is a risk factor for both overweight/obesity and chronic non-traumatic orthopedic injuries in a prospective cohort of Golden Retrievers. Our data suggest that gonadectomy at any age is a risk factor for overweight or obesity, but delaying gonadectomy until dogs are at least 6-12 months of age may help to decrease the risk for orthopedic injury.

Perceptions of community cats and preferences for their management in Guelph, Ontario. Part II: A qualitative analysis

Implementation of cat population management strategies that are effective and supported by the community requires knowledge of local contexts, public values, and preferences. From 2014 to 2015 the Guelph Cat Population Taskforce surveyed Guelph, Ontario residents to investigate attitudes and values concerning community cats and preferences for cat population management. Responses from 449 individuals were received through a combination of paper and online surveys. The results of a qualitative analysis of 7 open-ended survey questions are reported herein. Results indicate that community cat issues are largely attributed to perceptions of irresponsible pet ownership practices, highlighting the opportunity for public education. Participants identified the whole community as responsible for addressing the problem, suggesting the value of collaborative management approaches. This analysis also illuminated opportunities for combining well-supported strategies such as accessible or low-cost spay/neuter and trap-neuter-return (TNR) to implement a multifaceted approach. Overall, Guelph residents who responded to the survey gave a high priority to proactive, humane management of community cats.

Perceptions of community cats and preferences for their management in Guelph, Ontario. Part I: A quantitative analysis

In 2014, 116 Guelph residents were surveyed to investigate attitudes about community cats and preferences for population management. There are an estimated 29 579 owned cats in Guelph, an estimated 40% of residents allow outdoor access to their cat(s), and 8054 households (15%) feed community cats. Participants reported more concern with community cat welfare than nuisance behavior. There were high levels of support for responsible pet ownership education (90%), accessible or low-cost spay/neuter (86%), and trap-neuter-return (78%), and low levels of support for inaction (4%) and euthanasia (20%). Respondents who did not own cats or who considered cats as "pests" or a "non-native, invasive species" were more supportive of euthanasia. Results suggest that Guelph residents want to see action taken to address community cat population concerns, and that proactive management tools such as education, accessible or low-cost spay/neuter, and trap-neuter-return would be well supported and less divisive than euthanasia.

Outcomes of elective gonadectomy procedures performed on dogs and cats by veterinary students and shelter veterinarians in a shelter environment

OBJECTIVE To determine complication rates for elective gonadectomy procedures performed by veterinary students on dogs and cats in an animal shelter, characterize these complications, and compare rates with those for shelter-employed veterinarians (SEVs). DESIGN Retrospective cohort study. ANIMALS 10,073 dogs and cats for which gonadectomy was performed by a veterinary student (n = 3,048 surgeries) or SEV (7,025 surgeries) at an urban animal shelter over a 16-month period. PROCEDURES Electronic medical records for included dogs and cats were reviewed and data collected regarding patient signalment, duration of gonadectomy, surgeon type (student or SEV), and types of surgical complications recorded (including death or euthanasia) during the period from anesthetic induction to 72 hours after surgery. Complication and mortality rates were compared between veterinary students and SEVs. RESULTS No significant differences were identified between students and SEVs regarding rates of overall complications for both species, minor complications for both species, major complications for both species, and overall complications for dogs or cats specifically. The most common complications were self-limiting, with no long-term consequences, for both students and SEVs. Differences in mortality rates between students and SEVs could not be definitively determined owing to low numbers of nonsurviving patients. CONCLUSIONS AND CLINICAL RELEVANCE With judicious case selection and as a part of a surgical training program, complication rates for veterinary student-performed gonadectomy procedures for dogs and cats were no different from those for SEV-performed gonadectomy procedures. We believe such information regarding patient outcomes will allow shelter staff to make informed decisions and help them in discussions with stakeholders who may have concerns about student participation.

Exploring the Effects of Participation in a Shelter Medicine Externship on Student Knowledge and Self-Confidence

With the recognition of shelter medicine as a sub-discipline of veterinary medicine, many veterinary programs are including clinical shelter experiences in their curricula. A concurrent mixed-methods study was designed with the aim to determine the effectiveness of a 4-week clinical shelter medicine program on students' perception of canine and feline surgical proficiency and shelter medicine knowledge as well as gain information on student attitudes toward shelter medicine and interest in pursuing this career path. Year 4 veterinary students at Western University of Health Sciences who were enrolled in a shelter medicine externship from 2014 to 2016 were invited to complete pre- and post-course online surveys. Of the 168 enrolled students, 77.4% were invited to participate, and 114 completed the survey. There was no statistically significant difference in student veterinary career interest before and after completing the externship. There was an overall increase in student rating of their ability to perform six shelter medicine tasks as well as ovariohysterectomy/ovariectomy (OVH/OE) and castration surgeries after completing their externship; all were statistically significant ( p < .001). There was a statistically significant difference in the proportion of students who were familiar with the Asilomar Accords and the Association of Shelter Veterinarians (ASV) Guidelines for Standards of Care in Animal Shelters after completion of their externship ( p < .001). Students largely supported pediatric spay and neuter, stating it was an effective means of population control. Based on the themes that emerged from the qualitative analysis, it appeared most students had an accurate understanding of the term no-kill.

Effect of castration and carcass suspension method on the quality and fatty acid profile of beef from male dairy cattle

BACKGROUND

The use of bulls rather than steers for beef production offers some considerable advantages; however, the eating quality of bull beef is an issue of marketing concern. This study assessed the physicochemical characteristics of young Holstein-Friesian (HF) bull and steer beef. Steer carcasses were suspended by the Achilles tendon (AS) and by pelvic suspension (PS).

RESULTS

HF steer beef had higher redness, yellowness and chroma values, whereas bulls had higher ultimate pH and darker muscle. Warner-Bratzler shear force, cook loss at different ageing times, moisture, and insoluble and total collagen were higher for HF bull beef, whereas intramuscular fat, soluble collagen and collagen solubility were higher for steer beef. HF steer beef had a higher proportion of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA), whereas bull beef had higher proportions of polyunsaturated fatty acids (PUFA), PUFA/SFA and n-6/n-3 PUFA ratios. In comparison to AS, PS increased redness and chroma after 24 h blooming; PS improved tenderness up to 7 days of ageing and accelerated the ageing process.

CONCLUSION

For young dairy cattle, steer beef would likely have superior eating quality but a relatively less favourable nutritional fatty acid profile to bull beef. Suspension method affected the tenderness and colour intensity of dairy steer beef at different ageing times. © 2018 Society of Chemical Industry.

Impact of a trap-neuter-return event on the size of free-roaming cat colonies around barns and stables in Quebec: A randomized controlled trial

The objective of this study was to evaluate the impact of a trap-neuter-return (TNR) event on the size of free-roaming rural cat colonies in Quebec. This prospective randomized, controlled study included 18 cat colonies around barns and stables that were randomly assigned to either a TNR group (10 colonies of 7 to 27 cats; 14.3 cats on average) or a control group (8 colonies of 7 to 26 cats; 14.5 cats on average). The number of cats in each colony was calculated from the images obtained by camera-trapping at: baseline (T0), 7.5 mo (T7), and 12 mo (T12). At baseline, the TNR group was subjected to a TNR event. When taking into account adults only, a significant growth difference was observed in the number of cats between the TNR group and the control group at T7 (P = 0.03). When including kittens as well as adults, a trend towards a lower growth of the TNR group compared to the control group was noted at T7 (P = 0.06). There was no difference in the number of kittens between the 2 groups at T7 (P = 0.49) or at T12 (P = 0.36). There was a trend towards more emigration in the control group at T12 (P = 0.095). Isolated TNR events have a low and temporary impact on colony size in Quebec's rural cat colonies.

Behavioural risks in male dogs with minimal lifetime exposure to gonadal hormones may complicate population-control benefits of desexing

Castration of dogs is a widespread practise with clear justification in population control and knock-on benefits for animal welfare. Deleterious behavioural consequences of castration are believed to be negligible. Gonadectomy is widely recommended as part of a multi-factorial approach to prevent problems including aggression in dogs. However, the consequences of early castration on health are still being debated. The current study focused on the reported behaviour of 6,235 male dogs castrated before 520 weeks of life for reasons other than behavioural management, and calculated their percentage lifetime exposure to gonadal hormones (PLGH) as a proportion of their age at the time of being reported to the online Canine Behavioral Assessment and Research Questionnaire (C-BARQ). Forty behaviors differed between entire and castrated dogs, of which 25 were associated with PLGH and 14 with age-at-castration (AAC). Only 2 behaviours, indoor urine marking and howling when left alone, were significantly more likely in dogs with longer PLGH. In contrast, longer PLGH was associated with significantly reduced reporting of 26 (mostly unwelcome) behaviours. Of these, 8 related to fearfulness and 7 to aggression. The current data suggest that dogs’ tendency to show numerous behaviours can be influenced by the timing of castration. They indicate how dog behaviour matures when gonadal hormones are allowed to have their effect. The differences reported here between undesirable behaviours of castrated and intact dogs were in the range of 5.04% and 12.31%, suggesting that, for some dogs, partial or complete denial of puberty may reduce indoor urine-marking but have many other undesirable consequences. Veterinarians may use these data to discuss unwelcome consequences with owners of male dogs before castration.

Concomitant feline immunodeficiency virus (FIV) and Mycoplasma haemofelis in a barn cat

A 5-year-old male barn cat was presented with lethargy and excessive bleeding following castration. The patient developed hemolytic anemia and diagnostic tests revealed infection with feline immunodeficiency virus and Mycoplasma haemofelis. This case serves as a reminder of the importance of testing for infectious diseases and educating owners on feline infectious disease prevention and management.

Complications and risk factors of castration with primary wound closure: Retrospective study in 159 horses

Castration with primary wound closure reportedly has lower complication rates and shorter recovery periods compared to castration with second intention healing. However, little is known about risk factors associated with complications using primary wound closure. Medical records of 159 horses castrated and having primary wound closure were reviewed. Main short-term complications were: scrotal hematoma in 12 horses (7.6%), signs of colic in 6 horses (3.8%), fever in 4 horses (2.5%), and peri-incisional edema in 3 horses (1.9%). As for long-term complications, 24 out of 105 (23%) horses sustained some form of edema. One horse was euthanized because of a suspected inguinal abscess. Among tested parameters, horses aged 3 to 6 years old and French trotters appeared to be more at risk of developing complications. Intraoperative ligation of the cremaster muscle and use of electrocautery prevented complications. Overall, client satisfaction was excellent (98%).

The Association of Shelter Veterinarians' 2016 Veterinary Medical Care Guidelines for Spay-Neuter Programs

As community efforts to reduce the overpopulation and euthanasia of unwanted and unowned cats and dogs have increased, many veterinarians have increasingly focused their clinical efforts on the provision of spay-neuter services. Because of the wide range of geographic and demographic needs, a wide variety of spay-neuter programs have been developed to increase delivery of services to targeted populations of animals, including stationary and mobile clinics, MASH-style operations, shelter services, community cat programs, and services provided through private practitioners. In an effort to promote consistent, high-quality care across the broad range of these programs, the Association of Shelter Veterinarians convened a task force of veterinarians to develop veterinary medical care guidelines for spay-neuter programs. These guidelines consist of recommendations for general patient care and clinical procedures, preoperative care, anesthetic management, surgical procedures, postoperative care, and operations management. They were based on current principles of anesthesiology, critical care medicine, infection control, and surgical practice, as determined from published evidence and expert opinion. They represent acceptable practices that are attainable in spay-neuter programs regardless of location, facility, or type of program. The Association of Shelter Veterinarians envisions that these guidelines will be used by the profession to maintain consistent veterinary medical care in all settings where spay-neuter services are provided and to promote these services as a means of reducing sheltering and euthanasia of cats and dogs.

Perioperative analgesic use by Ontario veterinarians, 2012

The objectives of this study were to describe the routine use of analgesics by Ontario veterinarians for common surgeries in dogs and cats, and to compare routine use of analgesics between species and surgeries, using Chi-square analyses. In total, 239 veterinarians responded to the questionnaires; a response rate of 13.1%. Fifty-two percent to 79% of veterinarians used meloxicam for both species and all surgeries. Approximately 9% of veterinarians did not use analgesics for dog ovariohysterectomy and castration, while 16% to 22% did not use analgesics for these surgeries in cats. Veterinarians used and dispensed analgesics to dogs more often than to cats (P < 0.05). Many (60% or more) veterinarians administered analgesics pre-emptively to both dogs and cats for all surgeries. Continuing education for veterinarians needs to focus on understanding of pre-emptive analgesia, preventive analgesia, and the importance of dispensing analgesic drugs after surgery for all surgeries.

Spontaneous hormonal variations in male cats following gonadectomy

The increased prevalence of obesity after neutering in cats is problematic in veterinary practice. Although many factors seem to be involved, the role of prolactin (PRL) and insulin-like growth factor-I (IGF-I), both implicated in adipose tissue development and glucose intolerance, should be considered. Seven male cats were castrated when 11 months old. Body weight was then recorded for 56 weeks and PRL, IGF-I and leptin assayed for 44 weeks. Body weight increased steadily but only significantly after 36 weeks. It stabilised after 44 weeks, and the cats then gained about 20% of their initial body weight. IGF-I increased rapidly and was significantly higher by week 3. PRL and leptin increased with initial peaks during the eighth and eleventh weeks, respectively. This study confirms that castration rapidly modifies the hormonal balance, partly explaining the body weight increase, and that hormonal changes precede this body weight increase. Hyperleptinaemia is apparently a consequence of excess weight.

An Age-Associated Decline in Thymic Output Differs in Dog Breeds According to Their Longevity

The age associated decline in immune function is preceded in mammals by a reduction in thymic output. Furthermore, there is increasing evidence of a link between immune competence and lifespan. One approach to determining thymic output is to quantify signal joint T cell receptor excision circles (sj-TRECs), a method which has been developed and used in several mammalian species. Life expectancy and the rate of aging vary in dogs depending upon their breed. In this study, we quantified sj-TRECs in blood samples from dogs of selected breeds to determine whether there was a relationship between longevity and thymic output. In Labrador retrievers, a breed with a median expected lifespan of 11 years, there was an age-associated decline in sj-TREC values, with the greatest decline occurring before 5 years of age, but with sj-TREC still detectable in some geriatric animals, over 13 years of age. In large short-lived breeds (Burnese mountain dogs, Great Danes and Dogue de Bordeaux), the decline in sj-TREC values began earlier in life, compared with small long-lived breeds (Jack Russell terriers and Yorkshire terriers), and the presence of animals with undetectable sj-TRECs occurred at a younger age in the short-lived breeds. The study findings suggest that age-associated changes in canine sj-TRECs are related to breed differences in longevity, and this research highlights the use of dogs as a potential model of immunosenescence.

Anesthetic and physiologic effects of tiletamine, zolazepam, ketamine, and xylazine combination (TKX) in feral cats undergoing surgical sterilization

Tiletamine (12.5 mg), zolazepam (12.5 mg), ketamine (20 mg), and xylazine (5 mg) (TKX; 0.25 ml, IM) combination was evaluated as an anesthetic in 22 male and 67 female adult feral cats undergoing sterilization at high-volume sterilization clinics. Cats were not intubated and breathed room air. Oxygen saturation (SpO2), mean blood pressure (MBP), heart rate (HR), respiration rate (RR), and core body temperature were recorded. Yohimbine (0.25 ml, 0.5 mg, IV) was administered at the completion of surgery. TKX produced rapid onset of lateral recumbency (4±1 min) and surgical anesthesia of sufficient duration to complete surgical procedures in 92% of cats. SpO2 measured via a lingual pulse oximeter probe averaged 92±3% in male cats and 90±4% in females. SpO2 fell below 90% at least once in most cats. MBP measured by oscillometry averaged 136±30 mm Hg in males and 113±29 mm Hg in females. MBP increased at the onset of surgical stimulation suggesting incomplete anti-nociceptive properties. HR averaged 156±19 bpm, and RR averaged 18±8 bpm. Neither parameter varied between males and females or over time. Body temperature decreased significantly over time, declining to 38.0±0.8 °C at the time of reversal in males and 36.6±0.8 °C at the time of reversal in females. Time from anesthetic reversal to sternal recumbency was prolonged (72±42 min). Seven cats (8%) required an additional dose of TKX to maintain an adequate plane of anesthesia at the onset of surgery, and this was associated with significantly longer recovery times (108±24 min).

Extra-gonadal steroids modulate non-breeding territorial aggression in weakly electric fish

The neuroendocrine control of intraspecific aggression is a matter of current debate. Although aggression in a reproductive context has been associated with high levels of circulating androgens in a broad range of species, it has also been shown to occur during the non-breeding season when gonads are regressed and plasma steroid hormone levels are low. In mammals and birds the aromatization of androgens into estrogens plays a key role in the regulation of aggression in both the breeding and non-breeding seasons. This is the first study in a teleost fish to explore the role of steroids in the modulation of non-breeding aggression. Gymnotus omarorum is a highly aggressive teleost fish that exhibits aggression all year-round. We analyzed male-male non-breeding agonistic behavior, compared circulating 11-Ketotestosterone (11-KT) levels between dominants and isolated males, assessed the regulatory role of aromatization of androgens into estrogens, and evaluated the gonads as a source of these sex steroids. We found that high levels of aggression occurred in the non-breeding season despite low plasma 11-KT levels, and that there was no difference in 11-KT levels between dominant and isolated males. We demonstrated that acute aromatase inhibition decreased aggression, distorted contest dynamics, and affected expected outcome. We also found that castrated individuals displayed aggressive behavior indistinguishable from non-castrated males. Our results show, for the first time in teleost fish, that territorial aggression of G. omarorum during the non-breeding season depends on a non-gonadal estrogenic pathway.

Effect of high-impact targeted trap-neuter-return and adoption of community cats on cat intake to a shelter

Approximately 2-3 million cats enter animal shelters annually in the United States. A large proportion of these are unowned community cats that have no one to reclaim them and may be too unsocialized for adoption. More than half of impounded cats are euthanased due to shelter crowding, shelter-acquired disease or feral behavior. Trap-neuter-return (TNR), an alternative to shelter impoundment, improves cat welfare and reduces the size of cat colonies, but has been regarded as too impractical to reduce cat populations on a larger scale or to limit shelter cat intake. The aim of this study was to assess the effect of TNR concentrated in a region of historically high cat impoundments in a Florida community. A 2-year program was implemented to capture and neuter at least 50% of the estimated community cats in a single 11.9 km(2) zip code area, followed by return to the neighborhood or adoption. Trends in shelter cat intake from the target zip code were compared to the rest of the county. A total of 2366 cats, representing approximately 54% of the projected community cat population in the targeted area, were captured for the TNR program over the 2-year study period. After 2 years, per capita shelter intake was 3.5-fold higher and per capita shelter euthanasia was 17.5-fold higher in the non-target area than in the target area. Shelter cat impoundment from the target area where 60 cats/1000 residents were neutered annually decreased by 66% during the 2-year study period, compared to a decrease of 12% in the non-target area, where only 12 cats/1000 residents were neutered annually. High-impact TNR combined with the adoption of socialized cats and nuisance resolution counseling for residents is an effective tool for reducing shelter cat intake.

Effect of novel fiber ingredients on ileal and total tract digestibility of energy and nutrients in semi-purified diets fed to growing pigs

BACKGROUND

Consumption of different dietary fibers may influence the digestibility of carbohydrates and other nutrients. Therefore the objectives of this experiment were to determine the effect of novel fiber ingredients on the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of gross energy (GE), dry matter (DM), crude protein (CP) and total dietary fiber (TDF) in pigs and to calculate the standardized digestibility of analyzed TDF in four novel fiber ingredients.

RESULTS

The AID of DM and GE in diets containing novel fiber ingredients was less (P < 0.05) than in a maltodextrin diet. Addition of cellulose or pullulan, but not resistant starch (RS) 60, RS 75 or soluble corn fiber 70, reduced (P < 0.05) the AID of CP. The average ileal and total tract endogenous losses of analyzed TDF were calculated at 25.25 and 42.87 g kg⁻¹ DM intake, respectively.

CONCLUSION

Addition of novel fiber ingredients to a maltodextrin-based diet had different effects on the AID of DM, CP, GE and TDF. Measurements of the standardized digestibility of analyzed TDF may be a better indicator of TDF fermentability than measurements of AID and ATTD of TDF, because some endogenous metabolites may be analyzed as TDF.