The effects of short-term medroxyprogesterone acetate on rut related behaviors, semen characteristics and fertility in farmed reindeer bulls

Rowell, Janice E.; Geary, Tom; Blake, John E.; Zezeski, Abigail L; Shipka, Milan P.

doi:10.1016/j.theriogenology.2019.08.029

Cited by 3 publications

(1 citation statement)

References 36 publications

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“…Since these animals were immobilized at a resting state, they were not suffering from an increased oxygen demand associated with increased metabolic rate and body temperature, which often is the result of stress and chasing animals prior to darting (2). Further, none of these animals were pregnant or in rut, which represents additional physiological conditions in reindeer that may increase sensitivity to alpha-2 adrenoceptor agonists and contribute to side effects (2,12). In addition to the ambient temperature, which we have identified as the main variable when comparing the two rounds of immobilization, 11 of the 18 animals that were chemically immobilized a second round showed clinical signs of infectious keratoconjunctivitis (IKC) due to the inoculation with cervid herpesvirus 2 (4).…”

Section: Discussionmentioning

confidence: 99%

Case Report: Subclinical Verminous Pneumonia and High Ambient Temperatures Had Severe Impact on the Anesthesia of Semi-domesticated Eurasian Tundra Reindeer (Rangifer tarandus tarandus) With Medetomidine–Ketamine

et al. 2021

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Semidomesticated Eurasian tundra reindeer (Rangifer tarandus tarandus, n = 21) were scheduled twice for chemical immobilization with medetomidine–ketamine as part of a scientific experiment in June 2014. During the first round of immobilizations, seven animals developed severe respiratory depression (RD). Three individuals died, and 4 recovered. The ambient temperature during the 2 days of immobilization (June 3 and 4) was high (mean 13.9–17.6°C) compared to the normal mean temperature for these 2 days (7–8°C) based on statistical records. During the second round of immobilizations, using the same anesthetic protocol for the remaining animals as in the first round but conducted under cooler conditions (mean 6.6°C for the period June 9–18), no signs of RD were observed. Clinical and pathological investigations indicated that the animals suffered from circulatory changes possibly caused by high ambient temperatures and granulomatous interstitial pneumonia due to Elaphostrongylus rangiferi larvae. These conditions, together with the cardiovascular effects of medetomidine, were likely causes of RD and the fatal outcome. We conclude that chemical immobilization of reindeer with medetomidine–ketamine should be avoided in May–June due to the potential risk when animals partly in winter coats encounter rising ambient temperatures and usually have parasites developing in their airways.

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Section: Discussionmentioning

confidence: 99%

Case Report: Subclinical Verminous Pneumonia and High Ambient Temperatures Had Severe Impact on the Anesthesia of Semi-domesticated Eurasian Tundra Reindeer (Rangifer tarandus tarandus) With Medetomidine–Ketamine

et al. 2021

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Potential applications of assisted reproductive technologies (ART) in reindeer (Rangifer tarandus)

Lindeberg

Nikitkina

Nagy

et al. 2021

Animal Reproduction Science

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Medroxyprogesterone acetate in reindeer bulls: testes histology, cfos activity in the brain, breeding success, and semen quality

Rowell

Blake

Roth

et al. 2022

Journal of Animal Science

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A previous study reported that a 400-mg dose of medroxyprogesterone acetate (MPA) reduced male reindeer aggression and blocked development of secondary sexual characteristics but did not completely impair fertility. Here we have repeated that protocol in two separate trials. In 2017, tissues and blood samples, collected from MPA and control (CTL) reindeer bulls, euthanized at 30 and 60 d post-treatment were used to evaluate testes histology and morphometrics, cfos activity in the brain and androgen levels. While testes weight tended to decline from August to September in both groups, indices of spermatogenesis remained high. By September, indices of spermatogenesis were declining in both groups with sperm density lower (P = 0.05) in MPA compared to CTL bulls. Aug CTL bulls had the highest concentrations of androstenedione (A4) (P = 0.009) and testosterone (T) (P = 0.08), whereas these androgens were baseline in Aug MPA bulls. By September, A4 and T levels in CTL bulls declined to levels measured in MPA bulls. Cfos activity had a greater number (P = 0.02) of cfos positive neurons in the central amygdala in MPA compared to CTL bulls, suggesting a heightened fear response among the MPA bulls. In the second trial (2019), MPA-treated bulls, with (E, n = 4) and without (IE, n = 4) breeding experience, were blood sampled at key points from July through September when they were put in individual harems with estrous-synchronized cows. Concentrations of T were greatest (P < 0.001) among E bulls prior to MPA treatment but 1 mo after treatment, both T and A4 were baseline in all eight reindeer. Semen collected by electroejaculation at 60 d post-MPA treatment revealed only minor differences in sperm abnormalities between E and IE bulls using both fresh and frozen/thawed semen. Only three bulls (2 E and 1 IE) sired offspring. Breeding success was not related to previous breeding experience, body weight, or bull age. The failure of some MPA bulls to breed appears to be a behavioral, not a physiological, limitation. Limited application of MPA is clearly a useful tool for managing rut-aggression in non-breeding reindeer. However, the possibility that semen could be collected from MPA-treated bulls using restraint and mild sedation rather than general anesthesia should be investigated. This could improve the quality of semen collection while enhancing the safety of both handlers and animals.

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The effects of short-term medroxyprogesterone acetate on rut related behaviors, semen characteristics and fertility in farmed reindeer bulls

Cited by 3 publications

References 36 publications

Case Report: Subclinical Verminous Pneumonia and High Ambient Temperatures Had Severe Impact on the Anesthesia of Semi-domesticated Eurasian Tundra Reindeer (Rangifer tarandus tarandus) With Medetomidine–Ketamine

Case Report: Subclinical Verminous Pneumonia and High Ambient Temperatures Had Severe Impact on the Anesthesia of Semi-domesticated Eurasian Tundra Reindeer (Rangifer tarandus tarandus) With Medetomidine–Ketamine

Potential applications of assisted reproductive technologies (ART) in reindeer (Rangifer tarandus)

Medroxyprogesterone acetate in reindeer bulls: testes histology, cfos activity in the brain, breeding success, and semen quality

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