2 A dairy farmer uses artificial insemination (AI) to breed cows on the farm. (a) State what is meant by artificial insemination. [2] (b) Give three advanta...

(a) Artificial insemination (AI) is defined as the collection of semen from a selected male animal [1], followed by the deliberate introduction of that semen into the reproductive tract of a female animal using specialised equipment, without natural mating taking place [1]. The process bypasses the need for physical contact between male and female, allowing the farmer to control which genetics enter the herd.

(b) Three advantages of using AI instead of natural mating on a dairy farm:

1. Semen from genetically superior or progeny-tested bulls can be used, improving the genetic quality of calves without the farmer needing to own an elite bull [1].
2. A single ejaculate can be divided into many straws, so one bull can serve far more cows than would be possible through natural mating [1].
3. The risk of transmitting sexually transmitted diseases (such as trichomoniasis or brucellosis) is greatly reduced because there is no direct contact between animals [1].

Other acceptable advantages include: semen can be frozen and transported over long distances; no need to keep a dangerous bull on the farm (reducing costs and safety risks); and access to progeny-tested bulls for herd improvement.

(c) Prostaglandin (PGF2-alpha) [1]. This hormone causes the corpus luteum on the ovary to regress, ending the current luteal phase and triggering the cow to come into oestrus within a few days. GnRH or progesterone-based implants may also be used as part of a synchronisation protocol.

(d) Synchronising oestrus allows all cows to be inseminated at approximately the same time [1]. This is useful on a large dairy farm because it means calving dates are grouped together, making the management of calving, feeding schedules, and milking routines far more efficient and reducing the labour needed to monitor individual animals over a long calving season.