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The effect of LH concentration in a porcine pituitary extract and season on superovulatory response of Bos indicus heifers
THERIOGENOLOGY THE EFFECT OF LH CONCENTRATION IN A PORCINE PITUITARY EXTRACT AND SEASON ON SUPEROVULATORY RESPONSE OF BOS INDICUS HEIFERS H. Tribulo*, G.A. Bo, F. Jofre **, J. Car&o*,
A. Alonso* and R.J. Mapletoft
Department of Herd Medicine and Theriogenology, W.C.V.M., University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N OWO * Universidad National de Cordoba, ** Universidad Catolica de Cordoba, Argentina Willmott, et al. (Theriogenology 1990,33: 347) have previously shown that treatment of Bos mm~~ cows with FSH from a purified porcine pituitary extract or FSH with 16% LH contamination induced significantly more (PcO.05) corpora lutea (CL) (14.9; n=20 and 15.9; n=20, respectively), than FSH with 32% LH contamination or the unpurified porcine pituitary extract (100% LH) (8.3; n=20 and 9.2; n=2 1, respectively). In addition, the numbers of nonresponding cows decreased as the LH content of the pituitary extract decreased. An experiment was designed to determined the effect of LH contamination in a porcine pituitary extract on superovulatory response in Bos indicus heifers on pasture in Argentina during summer or winter. Ninety Brahman heifers were selected and divided in two replicates (winter and summer) of 45 heifers each. On days 8, 9 or 10 of the cycle (estrus = D 0) heifers in each replicate were placed at random into one of three treatment groups to be superstimulated with a total dose of pituitary extract equivalent to 400 mg NIH-FSH-PI over 4 days. Heifers in group I received a standard unpurified porcine pituitary extract (100% LH), whereas heifers in group II received a preparation with 84% LH removed (16% LH), and heifers in group III received a preparation with 98% LH removed (pure FSH). Forty-eight h after gonadotropin treatments were initiated all heifers received 500 ltg of cloprostenol IM and were inseminated 60 and 72 h later. On D 7 reproductive tracts were recovered at slaughter for ova/embryo collection and ovaries were examined for numbers of CL and follicles. Ova/embryos were classified as total (TOE) and fertilized (FO), however, the numbers of transferable embryos are not reported because of the period of time from slaughter to embryo collection. Overall, there were more ovulations (CL) in group III (Pure FSH), compared to group I (100% LH), with group II (16% LH) being not different from either (PcO.05). The numbers of heifers with no response also tended to decrease (P=O.O6) as LH concentration decreased; group I - 17 (63%), group II - 11 (41%), group III - 10 (34%). In addition, the percentage of large unovulated follicles classified as luteinized was 36%, 5%, 14% for groups I, II and III, respectively. Although superovulatory response did not differ between winter and summer in groups I and III, heifers in group II (16% LH) had a higher superovulatory response in the summer (P
I 100% LH II
16% LH
III Pure FSH
13
8.5
4.7
4.2
14
3.7a
5.9a* 1.6 0.8
4.4
3.4
12 19.2* 9.6
7.0
15
14 16.5
5.7
15 19.4b 10.6 8.3
7.0
27
6.0a
4.6
3.9
27 11.7ab 5.8
4.0
29 18.lb
6.8
8.5
ab - Means within a column with superscripts not in common are different (PcO.05) * - Group II differred between summer and winter (PcO.05) Data suggest that pituitary extracts with LH removed will improve superovulatory response in Bos indicus heifers and that more purified FSH extracts may be preferred for superovulation in winter months.
286
JANUARY 1991 VOL. 35 NO. 1
A. Alonso* and R.J. Mapletoft
Department of Herd Medicine and Theriogenology, W.C.V.M., University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N OWO * Universidad National de Cordoba, ** Universidad Catolica de Cordoba, Argentina Willmott, et al. (Theriogenology 1990,33: 347) have previously shown that treatment of Bos mm~~ cows with FSH from a purified porcine pituitary extract or FSH with 16% LH contamination induced significantly more (PcO.05) corpora lutea (CL) (14.9; n=20 and 15.9; n=20, respectively), than FSH with 32% LH contamination or the unpurified porcine pituitary extract (100% LH) (8.3; n=20 and 9.2; n=2 1, respectively). In addition, the numbers of nonresponding cows decreased as the LH content of the pituitary extract decreased. An experiment was designed to determined the effect of LH contamination in a porcine pituitary extract on superovulatory response in Bos indicus heifers on pasture in Argentina during summer or winter. Ninety Brahman heifers were selected and divided in two replicates (winter and summer) of 45 heifers each. On days 8, 9 or 10 of the cycle (estrus = D 0) heifers in each replicate were placed at random into one of three treatment groups to be superstimulated with a total dose of pituitary extract equivalent to 400 mg NIH-FSH-PI over 4 days. Heifers in group I received a standard unpurified porcine pituitary extract (100% LH), whereas heifers in group II received a preparation with 84% LH removed (16% LH), and heifers in group III received a preparation with 98% LH removed (pure FSH). Forty-eight h after gonadotropin treatments were initiated all heifers received 500 ltg of cloprostenol IM and were inseminated 60 and 72 h later. On D 7 reproductive tracts were recovered at slaughter for ova/embryo collection and ovaries were examined for numbers of CL and follicles. Ova/embryos were classified as total (TOE) and fertilized (FO), however, the numbers of transferable embryos are not reported because of the period of time from slaughter to embryo collection. Overall, there were more ovulations (CL) in group III (Pure FSH), compared to group I (100% LH), with group II (16% LH) being not different from either (PcO.05). The numbers of heifers with no response also tended to decrease (P=O.O6) as LH concentration decreased; group I - 17 (63%), group II - 11 (41%), group III - 10 (34%). In addition, the percentage of large unovulated follicles classified as luteinized was 36%, 5%, 14% for groups I, II and III, respectively. Although superovulatory response did not differ between winter and summer in groups I and III, heifers in group II (16% LH) had a higher superovulatory response in the summer (P
I 100% LH II
16% LH
III Pure FSH
13
8.5
4.7
4.2
14
3.7a
5.9a* 1.6 0.8
4.4
3.4
12 19.2* 9.6
7.0
15
14 16.5
5.7
15 19.4b 10.6 8.3
7.0
27
6.0a
4.6
3.9
27 11.7ab 5.8
4.0
29 18.lb
6.8
8.5
ab - Means within a column with superscripts not in common are different (PcO.05) * - Group II differred between summer and winter (PcO.05) Data suggest that pituitary extracts with LH removed will improve superovulatory response in Bos indicus heifers and that more purified FSH extracts may be preferred for superovulation in winter months.
286
JANUARY 1991 VOL. 35 NO. 1