Pakistan is blessed with a large livestock population well adapted to the local environmental conditions. Pakistan is home tract of best buffalo breeds of the world i.e. Nilli-Ravi and Kundi. Similarly, Sahiwal and Red Sindhi cattle are recognized milch breeds of zebu cattle with known resistance to hot weather and ticks. Although Pakistan ranks 4th in the milk production in the world, low productivity per animal is the major issue of our livestock. This low productivity can be attributed to many factors including poor genetic potential of a large number of animals, poor nutrition, inadequate veterinary health services, delayed puberty, long calving interval, acute shortage of quality breeding bulls and inefficient marketing. Livestock sector is still largely dependent on low technology and capital investment. Most of the dairy animals (>50 %) are owned and reared by smallholders keeping less then six animals per family in subsistence production system.
Reproductive efficiency is an important factor in determining the profitability of a dairy farm. Poor reproductive efficiency is caused by delayed maturity, high age at first calving ,longer calving interval and dry period. These factors not only result in reduced milk production at the farm but also shorten duration of milk production and animals produce less number of calves. Poor feeding is the principal cause of delayed puberty resulting in at least loss of one lactation per animal under local management conditions. Under field conditions, the average calving interval is around 18 to 24 months which can be reduced to 12 to 14 months with improved management of the farm animals. It is estimated that during productive life, each animal losses 2 to 3 lactations due to poor reproductive efficiency which badly affect the economics of dairy farming in the country.
Artificial Insemination (AI) is the deposition of semen (fresh, diluted or frozen) from male into proper place of female genitalia by mechanical means to make the female pregnant. Its history can be traced back as far as 1332 A.D to an Arab Horse Breeder. Scientific research on AI was first conducted by an Italian Physiologist on dogs in 1780. The AI is extensively being used in genetic up-gradation since 1930 throughout the world. The principle objective of AI is to utilize and widely spread genetic potential of a superior male on wider scale. Through AI, a bull can produce more than 500,000 calves in his life time. In Pakistan AI was started at College of Animal Husbandry, Lahore in 1954. Government of Punjab started 10 AI Centres at Changa Manga, Shiekhupura, Sialkot, Ghakhar, Nathuwal, Chakwal, Rawalpindi, Mianwali, Sargodha and Jhang using fresh semen. Use of frozen semen in AI was started in late sixties. Since then AI has spread to all other provinces and currently about 10-15 percent of breed able cows and buffaloes are serviced through AI. The success of AI depends upon many factors, the important being reproductive health of the animal, time of insemination, quality of semen and expertise of the technician. The selection of bull for use in AI is of prime importance as it transmits genetic characteristics to a large number of animals. To ensure the quality of bull for use in AI, elaborate systems of bull selection have been evolved and followed in the world.
Embryo transfer technology is a technology in which embryos from elite female are collected and transfer to other female animals. Both surgical and non surgical methods are available for embryo transfer but non surgical method is usually performed in cattle and buffaloes. It is one of the techniques for genetic improvement. The principal advantage of embryo transfer is increased reproductive capacity of a valuable female animal. Thus increased number of calves (usually 15-30 per year) can obtained from a genetically superior female cow/buffalo rather than getting one calf per 12-18 months. First successful embryo transfer was performed by Walter Heate in 1890 in rabbits. Embryo transfer in food animal began in 1930s in sheep and goat but it was not, until 1950s that successful embryo transfer was reported in cattle. However, most of the applicable embryo transfer technology, as it is practiced today, was developed in 1970s and 1980s. Embryo transfer is expensive technique, thus only practiced in elite animals. The standard embryo transfer procedure consist of treating donor female with the hormone which induces maturation and ovulation of large number of ova (this step is called superior ovulation). These ova after being fertilized through artificial insemination using semen of a superior bull are removed from the donor animal and transferred to foster female for gestation to complete. Embryo transfer involves number of steps and requires well trained personal and conscientious attention to detail.