Prediction of response to superovulation treatment in Bos indicus cattle by plasma progesterone estimation

PREDICTION OF RESPONSE TO SUPEROVULATION TREATMENT IN m INDICUS CAlTLE BY PLASMA PROGESTERONE ESTKMATION J. Dhanani, D. Jiiella and P.J. Chenoweth Department of Farm Animal Medicine and Production Uniwsity of St Lucia, Queen&n 8”“““” 4072, Australia The objective of this study was to assess the efficacy of using blood progesterone values to improve predictability of both donor selection and response to superovulatory treatment in -Bos indicus cattle. Brahman cows or heifers (n=97) were subjected to 4-day superovulato regimes using either Folltropin (18 mg) or FSH (38 mg), commencing on the 10 x day of oestrus, with subsequent i.m. PGF2a on the 3rd day of treatment, either 2 or 3 times at 12h intervals. Four inseminations were made at 12h intervals from standing heat Non-surgical flushes were performed at D7 foliowing oestrus. Peripheral blood samples were obtained by venipuncture on 5 occasions; at commencement of superovulation (DIO), at PGF2a injection (Dl3), at oestrus, at Plasma samples were analysed for total subsequent D3, and at flushing (D7). progesterone (P4) using RIA A res nse was considered positive if embryo(s) were recovered. The results appear in Joe following table. Table 1.

Owxall Anhnal Responses to Txeatmenks

No.

Responded (W

Non-response (W

CL

Recovered embryos

97

65 (67%)

32 (33%)

689

465

Transferable embryos 360

Responding females had an average of 10.6 CL detected, 7.2 embryos No CL were found in non-responding recovered . and 5.5 embryos transferred. females. Mean P4 values differed between responding and non-responding animals at commencement of superovulation and on D3 of treatment (1.58 f 0.58 and 2.00 No difference occurred between groups in P4 values at f 0.69 respectively). oestrus. However, mean P4 values differed significantly (PcO.01) between responding and non-responding animals on D3 following induced oestrus and on the day of flushing (3.90 i 0.64 and 10.89 f 1.54, respectively). P4 values at commencement of treatment were significantly (P
192

JANUARY

1991 VOL. 35 NO. 1