A look through the latest literature: reproduction - Veterinary Practice
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A look through the latest literature: reproduction

What’s new in reproduction? This summary of the latest academic publications covers this month’s spotlight topic of reproduction

Effects of vasectomy and ovary-sparing spay procedures on health and behaviour

Chris Zink and others, Zink Integrative Sports Medicine, Ellicott City, Maryland

Gonadectomy is widely carried out in dogs for population control and to reduce problem behaviour. However, the effects on canine health can be complex and may depend on the breed and age at which the procedure occurs. The authors compared the effects of traditional neutering procedures in male and female dogs with those subject to vasectomy or ovary-sparing neutering procedures. They obtained data from the owners of 1,056 intact, 1,672 castrated and 58 vasectomised dogs, along with 792 intact bitches, 2,281 spayed bitches and 159 bitches that underwent hysterectomies. Overall, they found that longer exposure to gonadal hormones, regardless of reproductive status, was associated with reduced odds of general health issues and different forms of problematic and nuisance behaviours.

Journal of the American Veterinary Medical Association, 261, 366-374

Impact of early castration on the physical and behavioural development of foals

Juliette Cognie and others, University of Tours, France

Castration of male equids has been practised since ancient times to produce a more biddable mount. This is usually carried out in animals at about 18 months old, or even later to allow the development of stallion-like morphological characteristics. The authors examined the effects of earlier procedures at around three days old on the development of Welsh ponies. They found no differences between the early and standard procedure groups in terms of physical development from birth until 40 months of age, or in terms of temperament and behaviour at either one or three years of age.

Equine Veterinary Journal, 55, 214-221

Prevalence of lactational oestrus in cats and the consequences for the kittens

Etienne Furthner, Vetmidi Veterinary Clinic, Etoy, Switzerland

While lactation and suckling may suppress fertility in mammalian species, some cat breeders have reported spontaneous oestrus during lactation, which appears to cause distress for the kittens. The author investigated the occurrence of this phenomenon in 238 litters from 23 different breeds. In 195 litters with a complete data set, 49 percent of the queens did go back into oestrus while lactating. This resulted in 38 percent of cases with a loss of maternal interest in suckling, changes in milk volume and quality, and detrimental effects on the health and welfare of the kittens. Litters born between February and April were at increased risk and there was also an association with small litter size.

Journal of Feline Medicine and Surgery, 25

Zinc oxide nanoparticle treatment improves the quality of preserved canine sperm

Eman Fayez and others, Cairo University, Egypt

Epididymal sperm cryopreservation is a valuable technique for assisted reproduction in conservation medicine and to preserve material from males that die unexpectedly. However, the process can lead to a reduction in the viability of the stored gametes due to damage caused by reactive oxygen species. The authors investigated the effects of adding zinc oxide nanoparticles as an extender for freeze-thawed epididymal dog spermatozoa. Samples taken from 22 dogs after castration were treated, frozen and thawed. Use of the extender led to a significant increase in the proportion of motile cells, increased viability and improvements in the integrity of the cellular membranes, acrosomes and DNA.

Topics in Companion Animal Medicine, 52, 100736

Infectious and non-infectious causes of abortion in horses

Germán Cantón and others, National Institute of Agricultural Technology, Argentina

Reproductive failure may occur in up to 40 percent of mares and is a major cause of economic losses for the equine industry. The authors investigated cases of abortion and stillbirth that were submitted to the main university laboratory in California between 1990 and 2022. Among 1,774 cases examined, a confirmed cause of abortion was identified in 29.2 percent. An infectious agent was isolated in 18.7 percent of cases, mainly Streptococcus sp., equine herpesvirus 1 or Leptospira sp. Non-infectious causes were established in 10.5 percent of cases, with umbilical cord torsion the most common finding.

Journal of Veterinary Diagnostic Investigation, 35

Thyroid hormones in canine pregnancy and lactation

Janna Hinderer and others, Free University of Berlin, Germany

Thyroid hormones are known to be critically important in human reproduction, influencing many different aspects of foetal development. However, there have been very few studies undertaken into their role in canine pregnancy. The authors measured thyroid stimulating hormone (TSH), free thyroxine, total thyroxine and progesterone levels at different points during pregnancy and lactation in 98 bitches and at equivalent times in 24 non-pregnant bitches. The study revealed changes in levels during the sexual cycle and pregnancy, suggesting that cycle stage is a factor that needs to be considered when assessing thyroid function in bitches.

Theriogenology, 203, 43-52

Prevalence and risk factors for caesarean sections in Bernese Mountain Dogs

Magdalena Schrank and others, University of Padua, Italy

Dystocia in bitches is a cause of maternal stress, puppy mortality and financial costs for the owner, and has a strong association with particular breeds. The authors investigated the incidence of dystocia in a giant breed, the Bernese Mountain Dog. They examined the records from 1,127 litters over a two-year period. The overall incidence of caesarean sections was 30.4 percent and the risks were significantly associated with the age of the dam, small litter size and a history of previous caesareans. In order to increase the survival rate of puppies they advise elective caesareans for pregnant bitches with any one of those three risk factors.

Acta Veterinaria Scandinavica, 64, 42

Treatment of a cystocele in a Doberman Pinscher three days after whelping

Carma Horwood and others, University of Guelph, Ontario

A cystocele is a type of vaginal prolapse that occurs in human patients in which the bladder herniates caudally into the pelvic canal and presses on the anterior vaginal wall. The authors describe the first reported case of a cystocele in a female dog three days after whelping and its successful surgical treatment with sparing of the reproductive tract. The case occurred in a three-year-old Doberman Pinscher bitch with a protruding vulva after delivering seven puppies in her third litter. The urinary bladder and vaginal body were reduced within the abdominal cavity and secured by cystopexy and cervicopexy, allowing the uterus and ovaries to be spared.

Canadian Veterinary Journal, 63, 1203-1207

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