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Effect of superovulation on milk production
THERIOGENOLOGY
EFFECT OF SUPEROVULATION ON MILK PRODUCTION A. Bak, T. Greve, M. Schmidt and T. Liboriussen' Department of Reproduction Royal Veterinary and Agricultural University Bulowsvej 13, 1870 Frederiksberg C, and 'National Institute of Animal Science, Foulum, Denmark Several studies have shown that certain high-yielding dairy cows may experience a drop in milk production following superovulation and nonwas undertaken to surgical collection of embryos. This investigation examine the effect of superovulation on milk production in donor cows that entered the national Banish embryo transfer program. High-yielding donor cows (n=130) with at least two normal estrous cycles were treated in their mid-luteal phase with 2250-3000 I.U. PMSG or 32-50 mg FSH followed 60-72 h later by a 0.75 mg cloprostenol injection to induce heat. Artificial insemination was performed approx. 60 and 72 h after prostaglandin administration and non-surgical recovery occurred 6-7 days later. Milk production (kg milk, % milk fat) of all donor cows was measured monthly in the official Danish milk recording system. Oata from at least the last two recordings (AI1 & AI) prior to the superovulatory treatment and the first (PI) after the embryo recovery were available from a total of 119 donor cows. Embryo recovery was performed an average (k SO) of 152.4 f 61.6 days after calving. The initiated 12 days earlier, and the superovulatory treatment was treatment period was considered to end 5 days after embryo recovery. Within this period (SO) a total of 59 recordings were carried out. the variance in the % milkfat (~~0.05) was During this period, significantly larger than the variance during the other production periods. In the period before treatment the average decline in daily butterfat production was 3.5 g/day, corresponding to 0.23% compared to 3.1 g/day (0.22%) in the period where superovulation and embryo recovery were carried out. In conclusion, the results of this study showed that milk production, in general, was not affected by superovulation and embryo recovery. Control milking
AI1
Days post partum
kg milk
(SD)
% milk
fat
g milk fat
33.5
(8.2)
4.64
(l.04)b
1528
AI so
125.4 152.4
31.3 29.1
(7.7) (7.5)
4.64 4.80
(l.02)b (1.25)a
1422 1397
PI
171.9
27.3
(7.1)
4.75
(l.Ol)b
1278
Means within (peO.05).
96.1
the same
column
with
different
-_ superscripts
are different
the last and the second last from control milking before treatment. SO: control milking within. PI: first control milking after treatment. The work was supported by grants from The Joint Collnittee for Agricultural Research and Experiments (A. Bak) and DANOVA LTD.
AI & AII:
170
JANUARY1989VOL.31NO.l
EFFECT OF SUPEROVULATION ON MILK PRODUCTION A. Bak, T. Greve, M. Schmidt and T. Liboriussen' Department of Reproduction Royal Veterinary and Agricultural University Bulowsvej 13, 1870 Frederiksberg C, and 'National Institute of Animal Science, Foulum, Denmark Several studies have shown that certain high-yielding dairy cows may experience a drop in milk production following superovulation and nonwas undertaken to surgical collection of embryos. This investigation examine the effect of superovulation on milk production in donor cows that entered the national Banish embryo transfer program. High-yielding donor cows (n=130) with at least two normal estrous cycles were treated in their mid-luteal phase with 2250-3000 I.U. PMSG or 32-50 mg FSH followed 60-72 h later by a 0.75 mg cloprostenol injection to induce heat. Artificial insemination was performed approx. 60 and 72 h after prostaglandin administration and non-surgical recovery occurred 6-7 days later. Milk production (kg milk, % milk fat) of all donor cows was measured monthly in the official Danish milk recording system. Oata from at least the last two recordings (AI1 & AI) prior to the superovulatory treatment and the first (PI) after the embryo recovery were available from a total of 119 donor cows. Embryo recovery was performed an average (k SO) of 152.4 f 61.6 days after calving. The initiated 12 days earlier, and the superovulatory treatment was treatment period was considered to end 5 days after embryo recovery. Within this period (SO) a total of 59 recordings were carried out. the variance in the % milkfat (~~0.05) was During this period, significantly larger than the variance during the other production periods. In the period before treatment the average decline in daily butterfat production was 3.5 g/day, corresponding to 0.23% compared to 3.1 g/day (0.22%) in the period where superovulation and embryo recovery were carried out. In conclusion, the results of this study showed that milk production, in general, was not affected by superovulation and embryo recovery. Control milking
AI1
Days post partum
kg milk
(SD)
% milk
fat
g milk fat
33.5
(8.2)
4.64
(l.04)b
1528
AI so
125.4 152.4
31.3 29.1
(7.7) (7.5)
4.64 4.80
(l.02)b (1.25)a
1422 1397
PI
171.9
27.3
(7.1)
4.75
(l.Ol)b
1278
Means within (peO.05).
96.1
the same
column
with
different
-_ superscripts
are different
the last and the second last from control milking before treatment. SO: control milking within. PI: first control milking after treatment. The work was supported by grants from The Joint Collnittee for Agricultural Research and Experiments (A. Bak) and DANOVA LTD.
AI & AII:
170
JANUARY1989VOL.31NO.l