Having spent over 30 years in the dairy artificial insemination (A.I.) industry, I have seen many changes. A majority of the changes have occurred through overall herd management practices in areas connected co cow care and comfort. A few examples include changes in herd sizes and facilities (stanchion barns to freestalls and pipelines to parlors). The industry has also seen practices such as grazing come full circle. Some of the changes introduced to the dairy genetics and A.I. sector have had a large impact on our industry. From new reproductive programs to the introduction of sexed semen and now the widespread use of genomics, these changes have all added important tools to the producer's toolbox.
The computer age brought about the introduction of software programs allowing the industry to become more efficient in applying and monitoring reproduction programs and herd events. Reproduction programs themselves have undergone many changes too. The introduction of prostaglandins in 19721 brought about the establishment of breeding protocol programs. For cows, these included: every Monday Lutalyse® program, Ovsynch®, Presynch®, Cosynch, Double Ovsynch®, G6G/Ovsynch® just to name a few. On the heifer side, many have also used EAZI-BREEDTM CIDRs® and Oral MGA.
My favorite protocol is Presynch with timed A.I. this is my favorite because, if followed properly, you will get 100% submission rate on all new animals entering the program. Conception rates may not be as high, but I am willing to sacrifice some conception results to attain 100% submission rate.
Real Example of Presynch with Timed A.I.
Let's look closer at this protocol: If 100 cows are enrolled and compliance is followed, the submission rate is 100 percent. If the herd's conception rate is 35 percent, we can assume 35 pregnancies are created in the first 21 days past the voluntary waiting period. In comparison, if visual heat detection is utilized on 100 cows with an average 60 percent heat detection, we have 60 cows inseminated within the first 21 days past the voluntary waiting period. Even if we assume a 50 percent conception rate, we have achieved 30 pregnancies. In order to equal the number of pregnancies created through the Presynch with timed A.I. protocol, a producer would need to attain 70 percent heat detection with a 50 percent conception rate! Many times these numbers are almost impossible to attain. Yes, there is a cost for running any synchronization protocol when drugs and labor are factored in, but don't forget to calculate the value of the additional pregnancies. Often times, this value far exceeds the cost of the program.
Over time, many changes have also taken place in how reproduction programs are monitored and how cows are managed. Indicators such as days in milk, days open, services per conception, calving interval or cull rate are great monitoring tools, but not the best. In my opinion, the best monitoring tool in today's fast-moving world is the 21-day pregnancy rate. This tells the level of success in finding heats and getting cows pregnant during the first 21 days after reaching the voluntary waiting period and every 21 days following. As always, in any good reproduction program, herd health, nutrition, compliance to protocol programs and teamwork play a major role.
The Role of Sexed Semen
In the last few years, sexed semen has been introduced for dairy and beef cattle. Although there has been negative press indicating sexed semen has caused lower milk prices. While sexed semen may be among the contributing factors, numerous variables come into play. The huge advantage sexed semen provides for producers needs to be addressed. Producers not only have the option to determine how many heifers to produce, but which cows or heifers they should come from. No one dictates that a producer has to raise every heifer calf; it's their individual choice. Each farm needs to consider their unique situation.
The Genomic Generation
None of the previous changes mentioned can match the opportunities that now exist with genomics. Genomics has shortened the generation interval within herds. The increase in speed at which genetic improvement can now occur is simply mind boggling. Through the use of genomics, we are able to determine a sire's genetic ability at 65 to 70 percent reliability before the bull even has milking daughters.
Genomic testing can also be conducted on females. In the last few months, the 3K chip has become available at a more reasonable cost. The 3K genomic test allows producers to test more females and gain production and trait information on them.
Which Tools to Use?
Today's dairy producers have several questions to ask. How do I position myself for the future? What breeding program will work best for me? What group of sires do I want to use on what group of heifers or cows? Should I use sexed semen? Do I need to raise every calf? Should I have more ‘do not breeds'? What do I want my cows to look like in the future and how will I achieve this?
With all these changes comes the knowledge to formulate different breeding strategies. No one knows for sure what new technology is yet on the horizon. All the tools listed above are available and can help a producer to position themselves for the future and the new things yet to come. The question remains, what technology fits with your long-term strategy to achieve the profits necessary for the future?
1Lauderdale, J. W. 1972 Effects of PGF2α on pregnancy and estrous cycles of cattle. J. Anim. Sci. 35:246