Why semen sorting could revolutionise dairy sector
Cattle husbandry in the past was an activity aimed mainly to cater to the farming operations.
But the utility of the cattle is diminishing due to mechanization, and the objective of cattle keeping is progressively turning towards dairying.
As per the estimates, the contribution of the draft animals to India’s total energy needs in the farming sector has reduced from the levels of 71% in 1961 to 23.3% in 1991. The declining trend continues and calls for production of more number of heifers. If, India has witnessed tremendous growth in dairy sector; it is mainly due to the growth in the crossbred population, which is growing at 7.6% annual rate.
Among the growing crossbred population, males have almost no value or negative value because of the declining need for draft animals coupled with the legal ban on cattle slaughter.
The crossbred male animals are eliminated either through early calf mortality due to neglect, or release into the village commons where they roam uncared for. The stray bulls become a nuisance due to the indiscriminate crossing and transmission of venereal diseases, and also cause damage and loss to farmers’ crops and a significant loss of feed resources.
The need of the hour is a technology that can boost production of crossbred heifers without generating unwanted males, is highly desired for building a profitable smallholder based dairy sector. The earliest research on semen sorting was done in the 1980s. This technology has been continually improving.
Sexed semen is assorted semen either containing X or Y chromosomes and the use of it would produce the desired sex – male or female animal. Semen sexing uses the principle of DNA concentration of X and Y chromosomes. X chromosomes contain 3.8% more DNA than Y chromosomes. The sorting of chromosomes (X or Y) is done using the flow – cytometer technology.
Semen sexing technology was introduced in the late 1990s in the domestic dairy industry.
Under Rastriya Krishi Vikas Yojana (RKVY), a pilot project has been taken up in Odisha for using 3,138 doses of Jersey sexed semen procured from VikingGenetics, Denmark.
Similarly, BAIF Development Research Foundation is also going to use sex-sorted semen in 25 high-performing Cattle Development Centres (CDCs) in five districts by March 2018. It is planned to use 5,100 sex-sorted semen.
The sorted semen from HF pedigreed bull namely, Regancrest Tabber Benhart and Phil – RU Bogart Kronk ET and Tollenaars Mascoltea 718 ET with an average milk yield of more than 12,500 kg per lactation will be used. Sorted semen from the Jersey pedigreed bulls, Wilsonview Jevon Magnum ET and GR Comsdale CC Celebrity Cindy ET with average milk yield of 10,403 kg per lactation and 9,566 Kg per lactation respectively, will be used.
These bulls have genetic merit to produce cows to yield maximum 40 litres milk per day.
This intervention will help the state to benchmark the conception rate of sorted semen under different agro-climatic and socio-economic conditions; and benchmark the conception rate of sorted semen in different categories of the cows like heifers and multiparous cows, of different localities; and to also benchmark the sexing ratio in the progeny produced from sorted semen usage.
Use of sexed semen will result in the birth of heifer calves 90% of the times in contrast to non-sexed semen, which could result in the birth of female calves only in 50% of the times.
Production of such genetically superior daughters will result in improving the desired traits in a shorter period, resulting in faster genetic progress. Use of sexed semen tends to produce more female calves, which biologically weigh less than the male calves and the percentages of difficult calving are reduced almost to half.
Reduced calving difficulties will help the cows to settle into milking quickly. The costs associated with handling difficult births and loss of calves could be reduced. The use of sexed semen will result in the elimination of the male calves right at the birth. This will result in the increased availability of feed and fodder resources. The overall reduction in the population will result in less production of methane and other greenhouse gases (GHGs) from livestock, which is a climate change mitigation measure.
The overall gain from the use of sorted semen will be much higher compared to the use of frozen semen. Our country needs to create own sex-sorted semen technology for the indigenous cow breeds like Gir, Rathi, Red Sindhi, Sahiwal, Binjharpuri and Haryana since the US companies have technology primarily for exotic cow breeds such as Holstein-Friesian and Jersey.
There are a large number of indigenous non-descript breedable cows; descript breedable cows and breedable she-buffaloes, and cross-bred breedable cows in the state. The cross-bred produce nearly 41% of the milk and they are more productive than the indigenous cows.
There is scope for huge improvement in total yields of milk in the state from indigenous non-descript cows by using sorted semen of indigenous cow breeds Gir, Red Sindhi, Sahiwal, Binjharpuri and Haryana. Small to moderate use of female sexed semen will increase the supply of replacement heifers enough to satisfy the demand and in turn would have a significant impact. Using sexed semen will increase the supply of good dairy cows, leading to overall enhancement of milk production.
All these efforts will make India’s milk revolution sustainable in days to come.