Background: Livestock is a major contributor to the national (11.9%) and agriculture (55.4%)
economy in Pakistan. Milk and meat are major livestock products of Pakistan, which is ranked
fourth largest milk-producing country in the world. The growth rate of dairy sector is growing
very fast for last several years, however, the genetic potential of elite cows is continuously
deteriorating due to unavailability of reproductive biotechnologies such as embryo transfer.
Normally one calf per year can be obtained from elite mothers. Maximum number of offspring
can be obtained by superovulation. This will helpful in production of genetically superior
offspring in limited time thus resulting in maximum exploitation of genetic potential of elite cows.
In Pakistan more than 80% farmers are small holder having 2-3 animals with low genetic
potential. The use of elite mothers by these farmers is limiting due to high cost. Superovulation
is a strategy that can be used to make low cost embryos available for small holders. This will
result in maximum spread of genetic potential of superior females. Use of follicular wave
emergence based super stimulation and timed ovulation with help of CIDR can improve the
results of super ovulation protocols and may be an effective tool to improve the per unit time
embryo production.
Hypothesis: Use of EB or GnRH in CIDR based superovulation protocols may result in
improved super ovulatory response in cattle.
Methodology: This study was conducted at Centre of Excellence for Bovine Genetics Embryo
Transfer Wing Okara. Seventy Donor cows (mix of crossbred and Holstein Frisian) were selected.
Animals coming into natural heat, were randomly assigned into one of the following
superovulation protocols; (A) In first group (n=37), which was considered as control, on 8th day
after heat animals were palpated for presence of a good quality CL and super ovulatory treatment
CHAPTER 6
SUMMARY
38
i.e. twice daily FSH injection were started on “Day 11” of its cycle for four consecutive days. On
day 3rd of FSH treatment PGF2α was injected both in the morning and evening. Animals were
inseminated in the morning and evening on the 5th day of superovulation treatment and next day
morning based on detected heat. Embryos were collected from the animal on 7th day after first
insemination. A PG injection was administered to the animal three days after embryo collection.
(B) In second superovulation protocol (n= 15), the animals were palpated for the presence of a
good quality CL on “Day 8” and a CIDR was placed after the confirmation of CL. An injection
of 2mg EB (Estradiol Benzoate) was also administered on the same day. Super ovulatory
treatment was initiated by “Day 11” of its heat cycle as narrated in first superovulation protocol
with only difference of CIDR removal along with 7th dose of FSH. Animals were inseminated
with a single straw of semen if on heat in the next day morning (Day 16 after natural heat) or with
double straw at “3 pm” if not on heat in the morning. Animals were also inseminated on next day
morning if heat sustained till next day morning. Animal were collected by non-surgical flushing
seven days after first insemination at super estrus. A PG injection was also given to the animals
three days after embryo collection. (C) In third superovulation protocol (n=18), the animal were
palpated for the presence of a good quality CL on “Day 8” and a CIDR was placed after the
confirmation of CL. An injection of “2ml Dalmaralin” was administered on the same day. Super
ovulatory treatment was initiated by “Day 11” of its heat cycle in similar sequence as narrated in
second superovulation protocol. At least 5 animals of each category (i.e. Crossbred and Holstein
Frisian) were treated with each super stimulatory protocol. In conclusion, CIDR plus GnRH or
CIDR plus EB protocols are better than normal superovulation protocol for embryo production in
cattle.
Summary
39
Outcomes: This study remained helpful to improve the existing superovulation protocols for
bovines with promising results which will help the genetic improvement programs of bovine in
Pakistan.