Roles of Hormones on Reproductive Performances of Domesticated Animals

Roles of Hormones on Reproductive Performances of Domesticated Animals

Dr. Debasish Behera, Dr. Dipanjan Chakroborty, Dr. Sukanta Datta and Dr. Sailen Deb

College of Veterinary Sciences and Animal Husbandry, R.K. Nagar, Tripura, West-799008

Introduction: A hormone is a physiologic, organic chemical substance synthesized and secreted by a ductless endocrine gland that passes into the circulatory system for transport. They inhibit, stimulate or regulate the functional activity of the target organ. Primary hormones of reproduction are primarily derived from following major systems/organs: Like hypothalamus, anterior and posterior lobes of the pituitary gland, gonads (interstitial tissues & CL), uterus and placenta and pineal gland.

Use of hormones: its name trade names, presentation and dose rate in the treatment of different reproductive problems of domestic and pet animals

1. Gonadotropin-releasing hormone (GnRH):

Gonadorelin and Buserelin are synthetic analogues of GnRH in which specific amino acid substitutions have been made in their molecular structure resulting in reduced susceptibility to proteolytic enzymes and greater affinity for binding to GnRH receptors. Therefore, GnRH analogue has got about ten times potency than natural GnRH.

2. Buserelin:

• Anoestrus – 20 µg (5 ml) inj, repeat after 8-22 days, if required.
• Delayed ovulation and Improvement of pregnancy – 10µg (i2.5 ml)inj 6-8 hours before or at the time of insemination.
• Follicular cyst – 5ml/inj, repeat after 10-14 days if required.
• Receptal 0.0042 mg/ml, 10 ml. vial.
• Other preparations are Gynarich-2.5 ml, 5 ml (INTAS), Pregulate2.5 ml (Virvac), Provago-2.5 ml (Brihans).

3. Gonadorelin:

• Cystic ovaries – 500 µg, repeat if required, In conjunction with AI – 250 µg.
• Postpartum anoestrus – 500 µg repeat after 1-3 weeks.
• Fertagyl -100 µ𝑔 /ml, 1 ml amp (Intervet Animal Health Ltd )
• Cystorelin- 50 µ𝑔 /ml, 2 ml amp and 10 ml vial (BCAHP)

4. Human Chorionic Gonadotropin (hCG):

It is a complex glycoprotein excreted in the urine of women during pregnancy. It has primarily similar effect to LH secreted by the anterior pituitary gland. Hence it is used as a substitute for the more expensive LH. It also has longer half-life than LH.

• Pharmacological action & indications and dose: hCG mimics the effect of LH causing ovulation.
• It promotes the formation and maintenance of corpus luteum in females. Delayed ovulation or anovulation – 1500 IU-I/M at the time of A.I.
• Follicular cyst- 3000 IU-I/M,
• Repeat breeders – Chorulon- 1500 IU-I/M. ( INTERVET)

5. Pregnant Mare’s Serum Gonadotropin (PMSG):

It is also a complex glycoprotein. It is extracted from mare’s serum during the first trimester of pregnancy. The effect of PMSG is similar to FSH.

• Pharmacological action: It induces follicular growth in inactive ovaries of matureanimals.
• Indications:Superovulation, True anoestrus.
• Commercially available products: Folligon 1000 IU vial (Intervet). Dose and route: 1500-3000 IU I/M or I/V.

6. Hydroxy-progesterone Caproate:

• Pharmacological action: It mimics the action of corpus luteum.
• Indications: met-estrus bleeding, threatened abortion or habitual abortion and early embryonic death.
• Dose and route: Met-estrus bleeding- 500 mg at the time of bleeding, repeat weekly interval for 2 occasions.
• Early habitual abortion – 500 mg after 1.5 months of pregnancy, repeat at every 10 days.
• Late habitual abortion 500 mg for 3 days followed by500 mg/week.
• Commercially available products: Duraprogen -250 mg/ml, 2ml. amp (Vetcare).
• P-depot -250 mg/ml, 2ml./ amp. (Sarabhai-Zydus)
• Progesyn- 250 mg/ml, 3 ml /amp (INTAS).
• Delvosteron: proligestone-Suppression of estrous. 1st injection – in pro-estrus, or in anoestrus.
• 2^ndinjection – 3 months after 1^st injection, 3^rd injection – 4months after 2^nd injection subsequent injections – at 5monthly intervals and Dose rate – 10/33 mg /kg body weight

7. Estrogen:

• Indications: Ripening of cervix in case of dystocia, chronic endometritis, pyometra, mummification, hydramnios and hydrallantois.
• Estrogen is used in the treatment of misalliance in the bitch.
• Commercially available products: Progynon depot (Oestradiol valerate) 10mg/ml,
• Dose: 5-10 mg/ml., repeat at 7-days intervals.
• Pregheat (Oestradiol benzoate) 1 mg /ml. Dose- 2 ml
• Pregheat equivalent to 2 mg Oestradiol Benzoate per animal i/m.
• Following an unplanned mating, to prevent pregnancy it is given @0.01mg/kg, on 0, 3^rd, 5^th and 7^th day after mating, administered either by s/c or i/m route.

8. Prostaglandins, Cloprostenol, dinoprost (Natural prostaglandin),

• Luprostiol and tiaprostare synthetic PGF2α or analogues available for use in veterinary practice.
• The corpus luteum is refractory (resistant) to the action of PGF2α analogues for at least 5 days after ovulation in mares, cows, and ewes but in sows, the refractory period is up to 11 days.
• In bitches and queens, the CL is generally unresponsive at any time after ovulation unless subjected to repeated doses. The primary effect of PGF2α on the reproductive system is regression of corpus luteum.
• Indications: pyometra, mummification, endometritis, luteal cyst, iInduction of parturition, synchronization of estrus, silent heat.
• Commercially available products and their doses are Cloprostenol, Vetmate (Vetcare) 2 ml. vial, Synchromate (Prima vetcare) 2 ml. vial, PREGOVA (virvac),
• Pragma (INTAS), Clostenol (Zenex AH),
• Cattle: 2 ml equivalent to 0.5 mg Cloprostenol per animal i/m inj.
• Dinoprost: Lutalyse (Novartis) 5 mg/ml, 10 ml vial, Dose 25 mg or 5 ml. i/m inj.
• Luprostiol: Prosolvin (Intervet) 7.5 mg/ml, 2ml. vial, Dose – Cow-15 mg. or 2 ml I/M,
• Heifer & mare – 7.5 mg. or 1 ml. I/M,
• Tiaprost: Iliren (Intervet) 0.196 mg/ml,10 ml vial Dose 3.5 ml I/V or 5ml I/M.

9. Oxytocin: Myometrial stimulant – Oxytocin stimulates contraction of the estrogen-sensitised myometrium.

• This activity may be of benefit in dystocia due to secondary uterine inertia.
• Oxytocin should not be used when dystocia is related to mal-position or mal-presentation or feto-maternal disproportion.
• Oxytocin is most effective when used in an intravenous drip in saline.
• Oxytocin must be used within 12 hours of calving, after which myometrial sensitivity to its action is reduced.
• Oxytocin has been recommended to evacuate the udder of the cow in the treatment of mastitis.
• Oxytocin injections are recommended to induce contractions of the uterus after caesarean section.
• Indications: Post-partum hemorrhage, retention of placenta, uterine inertia, uterine involution after dystocia, prolapse of uterus (after replacement), agalactia due to failure of milk let-down.
• Doses for obstetrical cases: milk let down: Cow 75-100 IU 10-20 IU, Sow 30-50 IU 5-20 IU, Ewe 30-50 IU 5-20 IU, Bitch 5-25 IU 2-10 IU, Queen 5-10 IU 1-10 IU,
• Commercially available products: Pitocin (Pfizer) 5 IU/0.5 ml, 0.5 ml. amp.
• Syntocinon (Novartis pharma) 5 IU/ml, 1ml

10. Myometrial Relaxants:

• These drugs cause relaxation of the uterus and are used to aid in obstetrical correction during dystocia and to facilitate handling of the uterus during caesarean section. These drugs are also used to facilitate replacement of a prolapsed uterus.
• They can be used to delay parturition during night so that greater observation and care are available during day time. They are used in heifers, so that calving can be delayed sufficiently to allow better relaxation of the birth canal and perineum.
• Pharmacological action: Clenbuterol and isoxsuprine are beta-adrenergic agents.
• The smooth muscles of the uterus contain β2adrenergic receptors.
• A beneficial effect of clenbuterol in cases of dystocia is an improvement in the supply of blood to the placenta and foetus. Therefore, viability of calves is unimpaired and subsequent fertility is normal.
• Indications: Dystocia, fetotomy, caesarean section, prolapse of uterus, parturition in night, parturition in heifers.
• Dose and route: Clenbuterol (Planipart 30 µg/ml). Cattle – 0.3 mg or 10 ml (total dose) I/M or slow I/V or 60 µg/100 kg. body weight
• Isoxsuprine –Duvadilan (abbott) 5mg/ml, 2ml/amp, Cattle 15microgram/kg,
• Valethamide Bromide: Pharmacological action: It is a quaternary ammonium compound, with peripheral actions similar to those of atropine enabling cervical dilatation. It acts like relaxin hormone.
• Indications: Inadequate cervical dilatation at the time of parturition, kinked cervix- Dose: Cattle and mare 40-50 mg I/M, sheep, goat, pig – 10-20 mg I/M, Dog, cat 5-10 mg I/M.
• Market preparations: Epidosin vet (10 mg/ml) 10 ml. vial; Epidosin (8 mg/ml) 1ml ampoule.

11. Antiprogestins:

• These are synthetic steroids which bind with great affinity to progesterone receptors without any of the effects of progesterone.
• In bitches, 2 antiprogestins have been studied, mifepristone and aglepristone.
• In pregnant bitches, mifepristone is effective if administered after day 30 of gestation.
• The oral administration of mifepristone @ 2.5 mg/kg, twice a day.
• Pregnancy is terminated without side effects within 3-4 days after treatment.
• Commercially available products: Mefipil 200 mg/tab, Mifegest 200 mg/tab, MT Pill 200mg/tab, and Unwanted kit 200 mg/tab.

12. Clomiphene citrate:

• Pharmacological action: Clomiphene inhibits negative feedback mechanism of estrogen on GnRH, enabling the release of GnRH from hypothalamus, inducing the ovulation.
• Indications: Anovulatory estrus;  repeat breeding; delayed puberty, anoestrus, silent heat, delayed ovulation.
• Dose: Cattle, horse, sheep, goat and pig- 1-1.5 mg/kg/b.w. for 5 days, Dog 25 mg/kg b.w. orally. Just before drenching the medicine, 125 ml 10% sodium bicarbonate or 1% copper sulphate should be drenched which closes the reticular groove so that the medicine goes to the abomasum.
• Market preparations: Fertivet 300 mg/tab, Clofert 25 mg.50 mg, 100 mg. and 300 mg/ tab

Corresponding Author: Dr. Debasish Behera, (M.V.Sc. and PhD)

Assistant Professor, Department of Veterinary Pathology,

C.V.Sc and A.H., R.K. Nagar, Tripura, West-799008

Email: behera.debasish1@gmail.com

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