Sexed Semen. Is It A Good Decision?
Looking at the pros and cons of sexed semen to see if it is a good decision for your operation.
What is Sexed Semen?
Sexed semen is what it sounds like. It is semen that has a larger concentration of male or female sperm. A flow-cytometer is used to separate the male and female sperm. This device can detect the 3-4% difference in the content of the DNA between the two sperm to separate them. The sperm is first diluted and then dyed. At 60 mph, the sperm travels through the flow-cytometer under pressure. This excites the dye which shows up more on X chromosomes. Since the X chromosomes admit more light, lab technicians can assign different charges to different sexed sperm. A charge deflector then splits sperm into its sex category. If the sperm is unidentified then it does not receive a charge and goes straight through (Morell. 2011). So why use sexed semen? There is some discussion in the dairy industry on the pros and cons to using this new technology. I elaborate on some of the main points below.
Morell, J.M., H. Rodriguez-Martinez. “Practical Applications of Sperm Selection Techniques as a Tool for Improving Reproductive Efficiency.” 23 June, 2011. http://Hindawi.com. 22 Oct. 2016. http://dx.doi.org/10.4061/2011/894767
1. More Ladies
A major goal of a dairy producer is to increase the number of heifers being added through reproduction. By increasing the number of females being born, a herd increases the number of replacements. This is one of the biggest economic factors in managing a dairy (McCullock et al., 2013). Bull studs claim a 90% purity in sexed semen. Meaning that 9/10 calves should be a heifer calf. Studies have shown this to be fairly accurate statement, making sexed semen economically attractive in this area. For a dairy operation, more replacements means less costs of purchasing additional replacements. It also allows operators to do more culling in order to improve the herd (Van Doormaal. 2010).
McCullock, K., D.L. Hoag, J. Parsons, M. Lacy, G. Seidel Jr., and W. Wailes. 2013. Factors effecting economics of using sexed semen in dairy cattle. J. Dairy Sci. 96:6366-6377.
Van Doormaal, Brian. “The Impact of Sexed Semen on Breeding, Management, and Profitability of a Dairy Herd.” Feb. 2010. Cdn.com. 2 Nov. 2016. file:///C:/Users/Samuel/Downloads/ImpactofSexedSemenCDNVersion-February2010%20(1).pdf
2. Decrease Dystocia
Dystocia is a costly ailment to producers affecting both dams and calves. Producers try to avoid dystocia when possible. One factor in causing dystocia is the sex of the calf. Bull calves tend to be larger, there for creating a greater risk of dystocia (Statham. 2015). In a study conducted by H.D. Norman, they found that when using sexed semen, difficult births decreased by 64% and 28% for cows and heifers (Norman et al., 2010). By taking away over a half and a quarter of births involving dystocia, producers will have less labor, and medical bills. This also will increase dam health and percent of live calves being born. Another factor to consider is that of your sire selection. By using sexed semen and expecting female claves, producers would not be subject to only high calving ease sires. They would be able to choose from more bulls with a lower calving ease, within reason (Van doormaal. 2010).
Norman, H.D., J.L. Hutchinson, R.H. Miller. 2010. Use of sexed semen and its effect on conception rate, calf sex, dystocia, and stillbirth of Holsteins in the United States. J. Dairy Sci. 93:3880-3890.
Statham, Johnathan. “Dystocia Management.” April 2015. Merckvetmanual.com. 2 Nov 2016. Web. http://www.merckvetmanual.com/mvm/management_and_nutrition/management_of_reproduction_cattle/dystocia_management.html
Van Doormaal, Brian. “The Impact of Sexed Semen on Breeding, Management, and Profitability of a Dairy Herd.” Feb. 2010. Cdn.com. 2 Nov. 2016. file:///C:/Users/Samuel/Downloads/ImpactofSexedSemenCDNVersion-February2010%20(1).pdf
3. Improved Genetics
Genetics are a huge part of the dairy industry. From high-flying show cows to the commercial cow that's being pushed to her max for production. Every dairy operation focusses on genetics at some level. Most sexed semen is produced from higher traited, more desirable bulls (Van Doormaal. 2010). Using sexed semen in a herd with these high ranking bulls increases the genetic value of progeny. When these progeny are 90% female, your replacements have that added genetic value increasing the next generations potential. In a study produced by the University of Aarhus Denmark, researchers concluded that by using sexed semen on all heifers, genetic value was increased by 2.7% (Sorensen et al., 2011). According to Van Doormaal, Using sexed semen of 90% progeny proven sires increased life time net merit by 7% in one generation of animals. These statistics are believable seeing that U.S. per cow milk production has continued to increase (Van Doormaal. 2010). To keep up with other producers and continue to produce high quality cows, sexed semen seems like a reasonable use for improving genetics.
Sorensen, M.K., J. Voergaard, L.D. Pederson, P. Berg, A.C. Sorensen. 2011. Genetic gain in dairy cattle populations is increased using sexed semen in commercial herds. J. Animal Breeding Gen. 128:267-275
Van Doormaal, Brian. "The Impact of Sexed Semen on Breeding, Management, and Profitability of a Dairy Herd." Feb. 2010. Cdn.com. 2 Nov. 2016. file:///C:/Users/Samuel/Downloads/ImpactofSexedSemenCDNVersion-February2010%20(1).pdf
4. Conception Woes
Sexed semen is not without some setbacks. Studies show that sexed semen ranges in its fertility percentage compared to conventional semen. Multiple studies had an average of twenty percent lower conception rates for Holsteins bred to sexed semen (Vries. 2015). A lower conception rate is a big deterrent to any breeding program. Using conventional semen, virgin heifers tend to have a 60-70% conception rate on their first service vs lactating cows who have a 40-50% conception rate for the first service. This coupled with a negative 20% conception rate with sexed semen makes it harder to get cows pregnant using sexed semen (DeJarnette et al., 2008).
DeJarnette, J. R.L Nebel, C.E. Marshall, J.F. Moreno, C.R. Mcleary, R.W. Lenz. 2008. Effects of Sex-Sorted Sperm Dosage on Conception Rates in Holstein Heifers and Lactating Cows. J. Dairy Science. 91:1778-1785.
Vries De Albert. “Economics of Sexed Semen in Dairy Heifers and Cows.” ufl.edu. Jan. 2015. 22 Oct. 2016. Web. http://edis.ifas.ufl.edu/an214
5. Cost Considerations
Sexed semen also has an increased cost. It takes an average of three services to get a cow pregnant again. Adding another service to this increases your reproduction costs. Using sexed semen comes with the average cost increase of $30 dollars a straw (Olynk et al., 2007). With increased service numbers due to decreased fertility, producers may have to invest more money than desired to get a better chance of getting a female. Other costs that relate to decreased conception rates are knowing that your animals days open will increase. For cows this hurts their production and keeps them in a positive energy balance longer. Keeping heifers out of the herd longer increases the cost to raise the animal. Also the older a heifer is when she enters the herd the less productive she will be (Vries. 2015). Increased costs and decreased fertility does not favor a good breeding program. Producers should consider all of these factors into their decision on whether or not to use sexed semen (Parsons. 2012).
Olynk, N.J., C. Wolf. 2007. Expected Net Present Value of Pure and Mixed Sexed Semen Artificial Insemination Strategies in Dairy Heifers. J. Dairy Sci. 90:2569-2576.
http://www.sciencedirect.com/science/article/pii/S0022030207717551
Parsons, Jay, K. McCullock, I. Roman-Muniz. “Extensions Guide to Sexed Semen: A Case Study.” Aug. 2012. joe.org. 2 Nov, 2016. https://joe.org/joe/2012august/rb7.php
Vries De Albert. “Economics of Sexed Semen in Dairy Heifers and Cows.” ufl.edu. Jan. 2015. 22 Oct. 2016. Web. http://edis.ifas.ufl.edu/an214
Works Cited
DeJarnette, J. R.L Nebel, C.E. Marshall, J.F. Moreno, C.R. Mcleary, R.W. Lenz. 2008. Effects of Sex-Sorted Sperm Dosage on Conception Rates in Holstein Heifers and Lactating Cows. J. Dairy Science. 91:1778-1785.
McCullock, K., D.L. Hoag, J. Parsons, M. Lacy, G. Seidel Jr., and W. Wailes. 2013. Factors effecting economics of using sexed semen in dairy cattle. J. Dairy Sci. 96:6366-6377.
Morell, J.M., H. Rodriguez-Martinez. "Practical Applications of Sperm Selection Techniques as a Tool for Improving Reproductive Efficiency." 23 June, 2011. Hindawi.com. 22 Oct. 2016. http://dx.doi.org/10.4061/2011/894767
Norman, H.D., J.L. Hutchinson, R.H. Miller. 2010. Use of sexed semen and its effect on conception rate, calf sex, dystocia, and stillbirth of Holsteins in the United States. J. Dairy Sci. 93:3880-3890.
Olynk, N.J., C. Wolf. 2007. Expected Net Present Value of Pure and Mixed Sexed Semen Artificial Insemination Strategies in Dairy Heifers. J. Dairy Sci. 90:2569-2576.
Parsons, Jay, K. McCullock, I. Roman-Muniz. "Extensions Guide to Sexed Semen: A Case Study." Aug. 2012. joe.org. 2 Nov, 2016. https://joe.org/joe/2012august/rb7.php
Sorensen, M.K., J. Voergaard, L.D. Pederson, P. Berg, A.C. Sorensen. 2011. Genetic gain in dairy cattle populations is increased using sexed semen in commercial herds. J. Animal Breeding Gen. 128:267-275
Statham, Johnathan. "Dystocia Management." April 2015. Merckvetmanual.com. 2 Nov 2016. Web. http://www.merckvetmanual.com/mvm/management_and_nutrition/management_of_reproduction_cattle/dystocia_management.html
Van Doormaal, Brian. "The Impact of Sexed Semen on Breeding, Management, and Profitability of a Dairy Herd." Feb. 2010. Cdn.com. 2 Nov. 2016. file:///C:/Users/Samuel/Downloads/ImpactofSexedSemenCDNVersion-February2010%20(1).pdf
Vries De Albert. "Economics of Sexed Semen in Dairy Heifers and Cows." ufl.edu. Jan. 2015. 22 Oct. 2016. Web. http://edis.ifas.ufl.edu/an214
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