Surgical (cosmetic) dehorning in cattle

Comparison of Genetic Merit for Weight and Meat Traits between the Polled and Horned Cattle in Multiple Beef Breeds

Breeding for polled animals is deemed the most practical solution to eradicate horns naturally and circumvent management costs and risks on health and welfare. However, there has been a historical reluctance by some farmers to select polled animals due to perceived lower productivity of their calves. This study has compared estimated breeding values (EBVs) between horned and polled animals (N = 2,466,785) for 12 production and carcass traits to assess historical (before 2000) and recent (2000-2018) genetic implications of poll breeding. Older generations of the polled animals in most breeds had significantly lower (Bonferroni-corrected p = 0.05) genetic merits for live (birth to maturity) and carcass weights, milk, meat quality, and fat content traits. Substantial gains of genetic potential were achieved during 2000 to 2018 in each breed, such that polled animals have significantly improved for the majority of traits studied. Generally, polled cohorts showed advantageous EBVs for live and carcass weights irrespective of the lower birth weights in some breeds. While Polled Brahman showed inferior production parameters, the poll genetics' effect size (d) and correlation (r) were very small on recent birth weight (d = -0.30, r = -0.08), 200 days (-0.19, -0.05), 400 days (-0.06, -0.02), 600 days (-0.05, -0.01), mature cow live weight (-0.08, -0.02), and carcass weight (-0.19, -0.05). In conclusion, although there is some evidence that historical selection for polled breeding animals may have reduced productivity, there is strong evidence that more recent selection for polled genotypes in the breeds studied has not resulted in any adverse effects on genetic merit.

Formation, structure, and function of extra-skeletal bones in mammals

This review describes the formation, structure, and function of bony compartments in antlers, horns, ossicones, osteoderm and the os penis/os clitoris (collectively referred to herein as AHOOO structures) in extant mammals. AHOOOs are extra-skeletal bones that originate from subcutaneous (dermal) tissues in a wide variety of mammals, and this review elaborates on the co-development of the bone and skin in these structures. During foetal stages, primordial cells for the bony compartments arise in subcutaneous tissues. The epithelial-mesenchymal transition is assumed to play a key role in the differentiation of bone, cartilage, skin and other tissues in AHOOO structures. AHOOO ossification takes place after skeletal bone formation, and may depend on sexual maturity. Skin keratinization occurs in tandem with ossification and may be under the control of androgens. Both endochondral and intramembranous ossification participate in bony compartment formation. There is variation in gradients of density in different AHOOO structures. These gradients, which vary according to function and species, primarily reduce mechanical stress. Anchorage of AHOOOs to their surrounding tissues fortifies these structures and is accomplished by bone-bone fusion and Sharpey fibres. The presence of the integument is essential for the protection and function of the bony compartments. Three major functions can be attributed to AHOOOs: mechanical, visual, and thermoregulatory. This review provides the first extensive comparative description of the skeletal and integumentary systems of AHOOOs in a variety of mammals.

Complications associated with surgical dehorning in goats: A retrospective study of 239 cases

OBJECTIVE

This article describes complications following surgical dehorning of goats.

STUDY DESIGN

Retrospective. Medical records of goats that underwent surgical dehorning were reviewed.

ANIMALS

Two hundred thirty-nine goats.

METHODS

The medical records of 239 goats, not previously dehorned by other methods, that were cosmetically dehorned between January 2006 and April 2016, were reviewed. Data retrieved from the medical records included breed, weight, the surgeon performing the procedure, intraoperative complications, and the occurrence of return visits to the teaching hospital because of complications related to the dehorning procedure. The owner of record then completed a standard questionnaire during a telephone interview.

RESULTS

One or more complications following the surgical dehorning procedure were reported in 93/239 (38.91%) of goats. Complications were divided into major and minor categories. Eighty-four of 239 goats (35.14%) had minor complications, 3/239 goats (1.26%) experienced major complications, and 6/239 (2.51%) had both major and minor complications. The mean weight of goats with complications was 29.73 kg compared to 24.91 kg for goats without complications. This difference was statistically significant (P = .015).

CONCLUSION

Surgical dehorning of goats results in a high rate of complications; however, the majority of these complications are minor and do not affect health and performance of the goats. Goats experiencing complications weighed significantly more than goats without complications.

CLINICAL SIGNIFICANCE

Surgical dehorning of goats requires minimal aftercare and results in a low rate of serious complications.

Bovine surgery of the skin

Occasionally, the bovine practitioner is presented situations requiring application of techniques regarding wound repair and healing. Less commonly encountered in bovine practice than equine practice for example, principles and management of traumatic wound healing should be regarded as similar. Frequently, bovine practitioners need to apply knowledge of healing principles when wounds are surgically induced during horn and mass removal. Consideration of surgical approach, tension-relieving techniques, and dermal transposition flaps (see the ocular surgery article by Schulz in this issue) can be applied effectively in bovine practice.

Surgery of the respiratory system

Diseases affecting the respiratory tract are common in cattle; however, surgery required for treatment of these diseases is infrequent. Therefore, veterinarians may be reluctant to perform these surgical procedures. Familiarity with the variety and complexity involved in various surgical procedures should reduce this anxiety. When used, surgery of the respiratory tract can offer significant benefit to the patient and profitable returns to the owner.