(Gonadorelin) on Pregnancy Rates in River Buffaloes

ArchiveIranian of JournalSID of Veterinary Research , University of Shiraz , Vol . 5, No . 2, Ser . No . 10, 1383, 2004

Short Paper Effect of GnRH analogue (Gonadorelin) on pregnancy rates in river buffaloes

Batavani, R.A.1* and Eliasi, K.2

1Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Urmia, Urmia, Iran 2Graduated from Faculty of Veterinary Medicine, University of Urmia, Urmia, Iran

*Correspondence: R.A. Batavani, Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Urmia, Urmia, Iran. E -mail: ra. [email protected]

Summary

Field trials were carried out to assess the effect of gonadorelin (Fertagyl ®, intervet, Holland) on pegnancy rates of river buffaloes . In this study 84 lactating cyclic buffaloes were randomly allotted to three treatment groups . ( 1) untreated control (n=40 ); (2) I.M. injection of 0.25 mg gonadorelin at the time of artificial insemination (n=20 ) and (3) I.M. injection of 0.25 mg of gonadorelin on days 11 to 13 post - insemination (n=24 ). Pregnancy was determined by rectal palpation of the uterus on days 42 to 55 after insemination . Pregnancy rates to first service (AI ) in groups 1, 2 and 3 were 25% , 55% and 58% , respectively . In groups 2 and 3, a greater proportion of buffaloes that received GnRH became pregnant comparing to that of those untreated (P<0.01 ). The results demonstrated that a single dose of the gonadorelin significantly improved pregnancy rates in buffaloes when administered at the time of AI or during th e mid luteal phase after AI.

Key words: GnRH agonist, Pregnancy rate, Buffaloes

Introduction et al., 1986; Ashworth et al., 1989). In attempts to reduce embryonic mortality and According to FAO (2000) there are about improve reproductive performances in sheep 166 million domesticated buffaloes (Bubalus and cattle, progesterone supplementation has bubalis ) in the five world continents. been employed during early pregnancy Subspecies of B. bubalis are referr ed to as river (T hatcher et al., 1994). However , this buffalo and swamp buffalo. Despite river and approach has produced contrasting results. swamp buffalo possessing a different number Another approach in reducing embryo loss of chromosomes , (2n=50 and 48, respectively ), during early pregnancy has been the they are able to interbreed and produce fertile administration of exogenous gonadotropin - hybrid progeny. Buffaloes play a prominent releasing hormone (GnRH). The effect of role in rural l ivestock production, particulary synthetic GnRH on conception rate in dairy in Asia where over 95% of the world buffaloes cows when injected at the time of artificial are found. Reproductive efficiency is the inseminatoin (Lee et al., 1983; Rosenberg primary factor affecting productivity which is et al., 1991; Mee et al., 1993) and between hampered in the female buffalo by inherent 11-13 days after insemination (Macmillan late maturity, poor estrous expression, disti nct and Thatcher , 1991; Rettmer et al., 1992 a ; seasonal reproductive pattern and prolonged Sheldon and Dobson, 1993; Singh et al., calving intervals (Singh et al., 2000). 2003) is widely used . In mares one report Moreover, preimplantation embryonic loss is shows that treatment with buserelin between the major limiting factor for obtaining days 8 and 12 after ovulation and service , optimum reproductive performance and increases the pregnancy rates (Newcombe inadequate luteal function has been shown to et al., 2001). Administration of GnRH on day be an important cause of embryo loss (Wilmut 12 post -ma ting has been shown to improve reproductive performance of ewes (Cam et

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al., 2002). It is thought that GnRH treatment behaviour or standin g heat) and visual may increase the chances of embryo survival observation of oestrus signs such as: by improving luteal function and/or interfering restlessness, bellowing, tumefaction of the with the luteolytic mechanism (Beck et al., vulva and clear vulval discharge 4 periods 1994; Birnie et al., 1997; Cam et al., 2002). daily , for at least 30 min . Buffaloes were Therefore, it seemed reasonable to evaluate inseminated, using fresh semen from one sire this strategy in buffaloes. The present clinical by one technician. The a nimals were trials were conducted to elucidate the efficacy randomly allotted to one of three treatment of single administration of a GnRH agonist groups. ( 1) Non- GnRH agonist treated as (gonadorelin) at the time of AI or between 11 control group (n=40); (2) I.M. injection of to 13 days after insemination on first service 0.25 mg gonadorelin (Fertagyl , Intervet, pregnancy rates in river buffaloes. Holland) at the time of artificial insemination (n=20) and (3) a single I .M. injection of the Materials and Methods same dose on days 11 to 13 after insemination (n=24). Pregnancy was A total of 84 lactating river buffaloes determined via rectal palpation of the uterus (Bubalus bubalis ), 4 to 12 year of age , 42-55 days post insemination. Data for weighing 430-650 kg were selected from a pregnancy rates were compared using the herd kept at the Buffalo Breeding Center in the (SPSS , version 10) Chi-square analysis and North -West of Iran. Buffaloes had a history of Fisher’s exact test. normal calving and had no clinically detectable abnormalities in their genital tracts.These Results buffaloes were housed in free stall confinement facility exposed to the natura l environment, The effects of gonadorelin injection at the allowance for shade, wallowing in pool, time of artificial insemination or 11 to 13 sluicing or spraying water to cool the animals days after insemination are presented in during the hot part of the day. The buffaloes Table 1. Pregnancy rates to first insemination were fed standard diet of chopped alfalfa, for buffaloes in groups 1, 2 and 3 were 10/40 concentrate, corn silage and apple pomace (25%), 11/20 ( 55%) and 14/24 ( 58%), silage. The experiment was carried out during respectively . In groups 2 and 3 a greater the months of June to October (30°C maximum proportion (30% and 33%) of buffaloes that atmospheric temperature), the time when received gonadorelin became pregnant ovarian activity normally commences in comparing to those of untreated animals buffaloes. Oestus detection was carried out by (P<0.01). penile deviated buffalo bull (heterosexual

Table 1: Effect of gonadorelin administration at the time of artificial insemination or on days 11 -13 post - insemination on pregnancy rates in river buffaloes

Treatment groups

Control Buffaloes treated Buffaloes treated on buffaloes at the time of AI days 11-13 post AI Number pregnant 10 11 14 Number barren 30 9 10 Total No. of buffaloes 40 20 24

Percent pregnant 25 55 58 Significance of difference P<0.01 P<0.01 From control

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Discussion artificial insemination at observed oestrus of normal and repeat breeder cows has been During the interval between fertilization reported to increase pregnancy rates in some and the process of implantation, some forms of experiments (Lee et al., 1983; Ax , 1985; embryonic sig naling are necessary for maternal Rosenberg et al., 1991) while others have recognition of pregnancy to occur and cause observed no improvement (Archbald et al, the hormonal changes to elicit the uterine 1993; Drew and Peter , 1994). The rationale transformation necessary for implantation. of this approach is presumably to induce Furthermore, it is during this period that most ovulation, luteinisation at the appropriate embryonic losses occur (Gandolfi et al., 1992). time relative to insemination an d its ability to In ruminants this period is characterized by increase progesterone secretion by the secretion of antiluteolytic factor, interferon tau developing corpus luteum (Lee et al., 1985; (INF -t) by the conceptus (Geisert et al., 1992; Mee et al., 1993). This might prevent early Robert et al., 1996; Spencer and Bazer 1996). embryonic loss and accounts for higher Evidence in cows suggests that embryonic conception rates. viability and growth rate during the first few Treatment of buffaloes with gonadorelin days of pregnancy are dependent on the once on days 11-13 after insemination concentration of circulating progesterone. A significantly improved pregnancy rates. delay in the postovulatory rise in progesterone Some researchers have also reported concentrations results in impaired embryonic increased pregnancy rates after development, whereas high progesterone administration of GnRH agonist on days 11 concentrations are associated with well to 13 post -insemination in cattle (Macmillan developed embryos that able to produce strong and Thatcher , 1991; Rettmer et al., 1992 a ; antiluteolytic signal. In fact there appears to be Sheldon and Dobson, 1993; Drew and Peter , a cause –effect relationship among optimal 1994), whereas others reported no beneficial progesterone production, embryo growth, effect (Jubb et al., 1990; Jayakumar and INF -t production and maintenance of corpus Vahida, 2000). Furthermore , one report luteum a nd hence pregnancy (Newcombe indicated that administration of buserelin in et al., 2001). Treatment with GnRH and its recipient cows on day 5 post embryo transfer analogues cause acute secretion of LH and increased pregnancy rate (Singh et al., 2003). FSH such that concentrations in peripheral In non-pregnant ruminants, during the normal blood are increased for 3-5 hours . GnRH - oestrous cycle the synthesis and release of induced alterations in the function of corpus prostaglandin F 2α ( PGF 2α) from the luteum or follicles appear to be indirect endometrium is stimulated by luteal oxytocin through alterations in LH and FSH secretion to cause regressinon of the corpus luteum. (Rettmer et al., 1992 b ; Thatcher et al., 1993). Oxytocin receptor concentrations increase Treatment of river buffaloes with during the luteal phase of the cycle, gonadorelin, a GnRH agonist at the time of simulated by oestradiol-17β produced from artificial insemination improved pregnancy waves of ovarian follicular growth. If rates compared with the control group. There is pregnancy occurs, both secretion of luteal no available similar information on the use of oxytocin and the development of endometr ial GnRH for buffaloes with which to compare oxytocin receptors are suppressed. Inhibition these results. However, recent findings of oxytocin secretion and suppression of indicated that Dalmarelin injection (GnRH receptor development may serve to save synthetic analogue) at the time of inseminat ion corpus luteum for pregnancy. It seems that improved the conception rates of repeat the mechanism involved in the effect of breeder Nilli -Ravi buffaloes during the low GnRH agonist on pregnancy rates is its breeding season (Ghulam et al., 2002). abil ity to luteinize or induce ovulation of Another one showed that gonadotrpins with ovarian follicle at mid -cycle following the prostaglandin F 2α can be safely used to induce acute onset of LH release after GnRH and synchronize oestrus in anestrous buffaloes injection. This may reduce oestradiol with good fertility (Thakur et al., 1992). The secretion from the ovarian follicles. Lack of administration of GnRH around the time of oestradiol late in the oestrus cycle probably

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preve nts the changes in uterine receptor mating on ovarian s tructure and plasma concentrations of oxytocin as well as other progesterone and oestradiol concentration in events that are prerequisite for luteolysis ewes . Anim . Sci ., 63 : 407 -412 . (Thatcher et al., 1993; Beck et al., 1994; Drew 7- Birnie, LM; Broadbent, PJ and Hutchinson, and Peter , 1994; Harvey et al., 1994; Mann JSM (1997 ). Failure of prostaglandin F 2α analogue to induce luteolytsis in GnRH et al., 1995; Beck et al., 1996; Birn ie et al., agonist treated heifers. Vet. Rec., 140 : 315 . 1997; Arikan and Pamukcu , 2001). By 8- Cam, MK; Kuran, M; Yildiz, S and Selcuk, E delaying luteolysis treatment with a GnRH (2002 ). Fetal growth and reproductive agonist, increases the chances for embryos to performance in ewes administered GnRH establish signals for maternal recognition of agonist on day 12 post -mating. Anim. Reprod. pregnancy before a new wave of estrogen Sci ., 72 : 73 -82 . secreting follicle develops and initiates 9- Drew , SB and Peter , AR (1994 ). Effect of luteolysis (Rettmer , 1992 b ). buserelin on preg nancy rates in dairy cows. The present study proved potential Vet . Rec ., 134 : 267 -269 . opportunities for use of GnRH agonist in a 10 - Gandolfi, F; Brevini, TAL; Modina, S and Passoni , L (1992 ). Early embryonic signals : range of pro -fertility applications in buffalo. embryo -maternal interactions before Further trials using gonadorelin in buffaloes implantation . Anim . Reprod . Sci ., 28 : 269 - are indicated to determine the optimum dose, 276 . proper time of treatment and mechanism 11 - Geisert, RD; Short, EC and Z avy , MT (1992 ). involved. Maternal recognition of pregnancy. Anim. Reprod . Sci ., 28 : 287 -298 . Acknowledgements 12 - Ghulam, A; Saeed, MA and Bashir, IN (2002 ). Use of GnRH to improve conception rate in repeat breeder buffaloes during the low The authors gratefully acknowledge breeding season . Pakistan Vet . J. 22 : 42 -44. facilities provided by the Buffalo Breeding 13 - Harvey, MJA; Renton, JP; Salaheddine, M Center of North -West of Iran and their and Robertson , L (1994 ). Ovarian and clinical colleagues. response of cattle to buserelin . Vet . Rec ., 134 : 168 -171 . References 14 - Jayakumar , C and Vahida , AM (2000 ). Effects of administration of a gonadotrophin 1- Archbald, LF; Sumarall, DP; Tran, T; Klap stein, releasing hormone an alogue at mid -cycle post - E; Risco , C and Chavatte , P (1993 ). Comparison insemination . Indian Vet . J., 77 : 454 -455 . of pregnancy rates of repeat -breeder dairy cows 15 - Jubb, TF; Abhayaratne, D; Maimo, J and given gonadotropin releasing hormone at or Andeson , GA (1990 ). Failure of an prior to the time of insemination. intramuscular injection of an analogue of Theriogenology . 39 : 1081 -1091 . gonadotrophin releasing hormone 11 to 13 2- Arikan , S and Pamukcu , T (2001 ). Role of days after insemination to increase pregnancy oxytocin and oxytocin receptors in the synthesis rates in dairy cattle . Aust . Vet . J., 67 : 359 -361 . of prostaglandin F 2α in ruminants. Kafkas 16 - Lee , CN ; Critser , JK and Ax , RL (1985 ). Universitesi Veteriner Fakultesi Dergisi . 7: 123 - Changes of luteinizing hormone and 128 . progesterone for dairy cows after 3- Ashworth , CJ ; Sales , DI and Wilmut , I (1989 ). gonadotropin releasing hormone at first post - Evidence of an association between the partum breeding. J. Dairy Sc i., 68 : 1463 -1470 . survival of embryo and p eriovulatory plasma 17 - Lee, CN; Maurice, E; Ax, RL; Pennington, progesterone concentration in ewe. J. Reprod. JA ; Hoffman , WF and Brown , MD (1983 ). Fertil ., 87 : 23 -32 . Efficacy of gonadotropin -releasing hormone 4- Ax , RL (1985 ). What causes cows to repeat ? administered at the time of artificial Dairy herd management . Feb ., 22 : 11 -12 . insemination of heifers and post -partum and 5- Beck , NFG ; Peters , AR and Williams , SP (1994 ). repeat breeder dairy cows. A m. J. Vet. Res., The effect of GnRH agonist (busere lin) 44 : 2160 -2163 . treatment on day 12 post - mating on the 18 - Macmillan , KL and Thatcher , WW (1991 ). reproductive performance of ewes. Anim. Prod., Effects of an agonist of gonadotropin - 58 : 243 -247 . releasing hormone on ovarian follicles in 6- Beck, NFG; Jones, M; Davies, B; Mann, GE and cattle . Biol . Reprod ., 45 : 883 -889 . Peters , AR (1996 ). The effect of GnRH 19 - Mann, GE; Lamming, GE and Fray, MD analogue (buserelin ) treatment on day 12 post - (1995 ). Plasma oestradiol during early

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