Multiple ovulation and ovum transfer in the goat.

Abstract

Proc. Aust. Soc. Anim. Prod. (1974) 10; 246 MULTIPLE OVULATION AND OVUM TRANSFER IN THE GOAT N.W. MOORE* Forty-three Angora does were treated with progesterone and an equine anterior pituitary extract to induce multiple ovulation at pre-determined times. Thirty-nine does were subsequently served by Angora bucks. They had shed 386 ova, of which 328 (85%) were recovered and 281 (86%) were fertilized. A total of 275 fertilized ova were transferred to 158 recipient feral goats in which the time of oestrus and ovulation had been controlled by the use of progestagen impregnated intravaginal 'sponges and pregnant mare serum gonadotrophin. Forty-six recipients subsequently kidded, producing 68 Angora kids. Multiple ovulation in donors, and control of and ovulation in recipients and donors was successfully survival and development to kids of transferred ova was suggested that the death of transferred ova was due to rather than to lack of viability of ova. I. INTRODUCTION the time of oestrus achieved, but the poor. It is maternal failure The value of the technique of ovum transfer for the rapid buildup in numbers of sheep carrying particular desired and heritable characteristics has been demonstrated (Moore and Shelton 1962), but results of similar studies in other species of farm animals are not available. The development of reliable methods of inducing multiple ovulation in donor animals selected for desired characteristics, and the effective control of the time of oestrus and ovulation in donor and recipients are essential pre-requisites of the technique of ovum transfer. The ultimate aim of the present experiment was to use the technique of ovum transfer to rapidly build up numbers of Angora goats, but before this could be achieved it was necessary to develop for goats, effective methods of multiple ovulation and of ovum transfer. II. MATERIALS AND METHODS (a) Donors Forty-three Angora does of mixed age were available. In an effort to control the time of oestrus and ovulation and to induce multiple ovulation, they were treated with progesterone and an equine anterior Progesterone was given daily by intramuscular pituitary extract (HAP). HAP was prepared as described injection (12 mg/day) for 16 to 18 days. by Moore and Shelton (1964). It was injected subcutaneously on three consecutive days commencing on the day before the final injection of progesterone and each doe received a total of 36 or 45 mg HAP divided equally between the three injections. After treatment, the donors were run with one of five entire Angora bucks equipped with ram harnesses and crayons. Four to five and one-half days after the donors were first detected in oestrus their reproductive tracts were exposed by mid-ventral The numbers of recent laparotomy under general anaesthesia (Nembutal). ovulations were recorded and the Fallopian tubes and uterine horns were flushed to recover ova. The media used for flushing and storage of ova * Department of Animal Husbandry, University of Sydney. 246 prior to transfer were Dulbecco Phosphate Buffer or TCM199 (C.S.L., Melbourne) enriched with 10% heterologous goat serum. (b) Recipients Three hundred and fifty-four feral goats were available as potential recipients. In an attempt to synchronize oestrus in the recipients with that in the donors, polyurethane intravaginal sponges impregnated with 20 mg 'Cronolone' were inserted and left in situ for 16 mto 22 days. One day before the withdrawal of sponges the recipients were given a single subcutaneous injection of 600 1-U. pregnant mare serum gonadotrophin (PMSG). After sponge withdrawal the recipients were run with harnessed vasectomized bucks and they were inspected for oestrus twice daily at 06.00 and 18.00 hours. Transfers were carried out surgically under general anaesthesia. One to four fertilized ova were transferred to the uterine horns of recipients which had been first observed in oestrus over the period 24 hours before to 36 hours after, their respective donors, III. RESULTS (a) Donors Thirty-nine of the 43 donors were served following treatment (Table 1) and of the 39 which were served, 31 were first observed in oestrus within two days of the final injection of HAP. The 39 does had shed, as estimated by numbers of corpora lutea, a total of 386 ova, of which 328 (85%) were recovered and 281 (86%) of the recovered ova showed apparently normal cleavage and were considered to have been fertilized. TABLE1 Response of Angora does to an equine anterior pituitary extract (HAP) (b) Recipients Of the 354 does treated 56 lost their sponges and were discarded. Of the remaining 298 which retained their sponges, 210 (70%) were served, 192 (91%). within two days of the withdrawal of sponges (Table 2). 247 TABLE 2 Number of recipient does served following treatment with intravaginal sponges containing 20 mg 'Cronolone' Fertilized ova were transferred to 158 recipients of which 46 subsequently kidded, producing 68 kids (Table 3). TABLE 3 Kidding performance of recipients There were no significant effects of degree of asynchronization between the time of onset of oestrus in respective donors and recipients, of age of ovum at the time of collection, or of type of flushing medium used for the recovery and storage of ova on the proportion of recipients that kidded. There was a minor effect of number of ova transferred to individual recipients. Of 66 does which received one ovum, 13 kidded, whereas 33 of 92 which received more than one ovum subsequently kidded (P ' 0.05). IV. DISCUSSION The first aim of the experiment, that of developing a successful method of multiple ovulation at preidetermined times, was achieved. There appeared to be no adverse effects of treatment on either the proportion of ova which were recovered or the proportion which were fertilized, and it may be that higher ovulation rates could have been achieved by increasing the dose of HAP. Further, the use of progestagen impregnated sponges and 248 PMSG gave a substantial degree of control of the time of oestrus and ovulation in the recipient does. However, the subsequent survival and development of the transferred ova was disappointing, but the reasons for the subsequent loss of 207 of the 275 ova (75%) which were transferred to recipients remains There was no evidence of abortions or resorption of foetuses obscure. at any stage of gestation and at no stage during gestation did the animals suffer from any extremes of environmental conditions. The number of ova transferred had only a minor effect upon the Further, where two proportion of recipients which subsequently kidded. and three ova were transferred, 20 of the 33 recipients which subsequently kidded had more than one kid. Therefore, it would appear that the loss of transferred ova was, to a large degree, due to complete failure of the recipients to support the transferred ova rather than to lack'of viability of the transferred ova.. V. ACKNOWLEDGEMENTS Grateful acknowledgement is made to the Directors, Management and staff of the Australian Mohair Company, 'Wilbertree', Brewarrina, for the provision of animals, and in particular to the Manager, Mr Geoff Goddard, for his invaluable assistance. The author is indebted to Mr Alan Trounson and to Mr Ken Old for their help in the experiment. Financial assistance was provided by the Austr alian M o h a i r Research Foundation I to whom grateful acknowledgement is made VI. REFERENCES Aust- J. agric. Res. 13: 718. J. Reprod. Fert. 7: 79. = MOORE, N-W., and SHELTON, J-N. (1962). MOORE, N-W., and SHELTON, J-N. (1964). 249