Use of melengestrol acetate in feed for contraception in herds of captive ungulates

Raphael, Bonnie L.; Kalk, Penny; Thomas, Patrick R.; Calle, Paul P.; Doherty, James G.; Cook, Robert A.

doi:10.1002/zoo.10096

Cited by 12 publications

(5 citation statements)

References 3 publications

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“…Despite the small number of animals used in the present study, our results suggest a suppressive effect on estrous behavior in M. gouazoubira, when offering 1.0 mg/animal/day of MGA to females (Experiment 1), similar dose that has been used for contraception proposes in other deer species and members of the family Bovidae (Roughton 1979;Raphael et al, 2003;Patton et al, 2007). On the other hand, an MGA-based synchronization protocol with daily administration of 1.0 mg/animal/day (Experiment 2) did not demonstrate an efficient estrous synchrony, due to wide range at the time of onset of estrous behavior (12 to 72 hours).…”

Section: Discussionmentioning

confidence: 57%

“…Besides, it is a cheaper and less risky alternative for these species. To date, MGA is used for contraceptive proposes in deer such as white-tailed deer ( Odocoileus virginianus ) to control population growth in zoos ( Roughton, 1979 ; Raphael et al, 2003 ), but there are no reports of MGA applied to estrous synchronization protocol in deer.…”

Section: Introductionmentioning

confidence: 99%

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Low invasive estrous synchronization protocol for wild animals: an example with melengestrol acetate in brown brocket deer (Mazama gouazoubira)

et al. 2020

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Deer are sensitive to stressful stimuli by handling and their reproductive physiology could be altered by these procedures, making it necessary to develop less invasive protocols for ART. Melengestrol acetate (MGA), a synthetic progestin administered orally, appears as an alternative for estrous synchronization protocols (ESP), such as reported in cattle. Firstly, we compared two MGA doses (0.5 and 1.0 mg/day/animal), which would have suppression effect in estrous behavior (EB). Eight females were randomly and equally distributed in Group 1 (G1) and Group 2 (G2), which received 0.5 and 1.0 mg/day/animal respectively for 15 days (D1 to D15). Two cloprostenol (CP) applications were performed on D0 and D11. Estrus detection (ED) was performed every day. All females from G1 displayed estrus during treatment period, whereas all females from G2 displayed estrus after treatment, suggesting a suppressive effect of 1.0 mg in the EB. Once the suppressive MGA dose (1.0 mg) was defined, we used this dose for assessing ESP. The same eight females received 1.0 mg/animal for eight days (D-8 to D-1), followed by 0.25 mg of estradiol benzoate on D-8 and 265 μg of CP on D0. Feces for fecal progesterone metabolites (FPM) measurement were collected from D0 until seven days after the last day of estrus. Seven females displayed estrus between 12 and 72 h after CP application, which was followed by a significant increase in FPM levels (except female MG6), suggesting the formation of corpus luteum. After ED, females were placed with a fertile male to assess the fertility of the protocol. Pregnancy was confirmed by ultrasound 30 days after mating in 3/6 individuals. Although the low effectiveness of MGA protocol, it should be considered as a promising alternative in deer ESP since this protocol has less stressful effect on the animal during reproductive management when compared to other ESP.

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Section: Discussionmentioning

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Low invasive estrous synchronization protocol for wild animals: an example with melengestrol acetate in brown brocket deer (Mazama gouazoubira)

et al. 2020

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“…There were no observed adverse effects from MGA treatment on gestation. However, posttreatment reproductive rates were lower than pretreatment rates [Raphael et al, 2003].…”

Section: Melengestrol Acetate In Feedmentioning

confidence: 74%

Review of contraception in ungulate species

Patton

Jöchle

Penfold³

2007

Zoo Biology

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Most ungulate species are herd animals. In captivity, and increasingly so in the wild, space constraints limit natural behaviors associated with group dynamics, possibly resulting in inbreeding and/or overpopulation. This situation has necessitated research regarding contraception of various species of hoofstock. Differing management situations mandate different contraception protocols to achieve optimal results. Fertility control in hoofstock has been achieved through a number of different contraceptive methods predominantly surgical sterilization, mechanical contraception, synthetic steroid hormones, and immunocontraception. In this study successes and limitations of these techniques are reviewed. Zoo Biol 26:311-326, 2007. (c) 2007 Wiley-Liss, Inc.

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“…Testosterone is converted to estradiol, which stimulates the production of egg yolk precursors in the liver. Both progestins (a synthetic compound that mimics progesterone) and antiprogestins have been utilized as methods of inhibiting steroid hormone production, particularly in zoos (Jewgenow et al 2001, Raphael et al 2003. In addition, compounds that inhibit synthesis of steroid hormones by decreasing cholesterol synthesis or by preventing the conversion of cholesterol to pregnenolone have been tested (Yoder et al 2004).…”

Section: Steroid Hormonesmentioning

confidence: 99%

Avian Contraceptive Tools: One Size Does Not Fit All

ChristiA¹,

LowellA²

2006

vertebrate_pest_conference

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Avian contraception is a nonlethal management tool that can be utilized in conjunction with other management techniques to help manage bird populations causing damage. Because management situations vary with respect to the type of damage, species involved, location, and nontarget hazards, it is necessary to develop multiple contraceptive tools to allow management flexibility. DiazaCon ™ and nicarbazin have already been developed at the National Wildlife Research Center as avian contraceptives. Although both of these are promising contraceptive agents, more are needed for a wider variety of situations. Current research is focusing on other cholesterol inhibitors, inhibitors of the P450 side chain cleavage enzyme, and aromatase inhibitors. Because cholesterol is needed for steroid reproductive hormone production, inhibition of cholesterol impairs reproduction by preventing the formation of the necessary hormones. The P450 side chain cleavage enzyme is needed to convert cholesterol to pregnenolone, the precursor to progesterone and testosterone. Progesterone is needed for egg formation, ovulation, and oviposition, and testosterone is needed for sperm production. Aromatase is needed to convert testosterone to estradiol, which is needed in females to stimulate the production of egg yolk precursors in the liver. Inhibition of either of these enzymes should result in impaired reproduction. In the future, natural plant products with contraceptive activity, such as neem seed, will also be investigated. Because development of avian contraceptives is time intensive, an efficient screening process needs to be in place. Population models can assist in choosing specific agents to test for a given species and management situation. Although contraception is unlikely to be useful as a stand-alone tool, it can be included in integrated management plans.

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Use of melengestrol acetate in feed for contraception in herds of captive ungulates

Cited by 12 publications

References 3 publications

Low invasive estrous synchronization protocol for wild animals: an example with melengestrol acetate in brown brocket deer (Mazama gouazoubira)

Low invasive estrous synchronization protocol for wild animals: an example with melengestrol acetate in brown brocket deer (Mazama gouazoubira)

Review of contraception in ungulate species

Avian Contraceptive Tools: One Size Does Not Fit All

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