You spend hours pouring over the data of various bulls in different AI company catalogs, trying to find the perfect match for your cow herd and heifers. Then you find what you think will make a great pairing and decide to order the semen as breeding season nears.
But all that effort you spent analyzing the data to make an ideal mating may not be much use if you have low conception rates due to inadequate preparation or faulty equipment. Follow these tips to make sure you're doing everything possible to make AI breeding a success.
Facilities and equipment
The semen tank is an important piece of equipment considering it's the storage center for your investment. Begin by looking at where you keep the semen tanks. These should be in a well- ventilated but protected area to keep clean, dry and out of the sun. Also, consider placing a pallet or boards under the tanks to raise them off the ground to prevent moisture from gathering on the bottom causing rust or corrosion. Try to eliminate any unnecessary movement of the tanks, since increased movement increases the likelihood of damage.
To keep the semen frozen yet viable when thawed, check the tanks" nitrogen levels regularly for changes in temperature. You also may want a good backup tank in case a tank fails. Frost on the tank is an indication that liquid nitrogen has been or is evaporating. Glenn Selk, beef cattle reproduction specialist at Oklahoma State University, says that if you suspect this is happening, use a wooden yardstick to measure the amount of liquid in the tank. If there is still liquid nitrogen in the tank, immediately transfer the semen to a good tank. If there is no liquid nitrogen remaining, the semen may be ruined and should be evaluated to determine if it is still viable.
Dr. Selk adds that one of the details that is often overlooked when checking equipment is the accuracy of the thermostat on the thaw thermos. The recommended temperature of the thawing water is 95'F to 98'F, and when that varies too much, then semen fertility is negatively impacted. He says, "You need to check these thermometers before each breeding season against a reliable mercury- type thermometer." Adjust the dial thermometer on the thermos by using a box-end wrench on the collar below the dial, then use vice-grips or pliers to turn the rim of the dial to get the thermometer to the right reading.
In addition, the working facilities used to AI cows should be checked prior to breeding to ensure everything is in working order so that cows and heifers can be worked with minimum stress. Make sure your chute is modified to facilitate AI with ample room so the technician has room to do the necessary work.
Besides the physical facilities and equipment, you need to make sure your cow herd or heifers are ready for AI. Nutrition is a key component for any successful breeding program, and numerous research studies show that cows and heifers in thin condition going into breeding season typically have delayed estrous, which lowers conception rates.
"Make sure you have a good understanding of the body-condition scoring system," recommends Rick Rasby, University of Nebraska beef cattle specialist. He says this is especially important for young cows and heifers. If cows and heifers that you're considering for your AI program are less than a body-condition score 5, then consider supplemental feeding to improve that condition with an energy-rich supplement.
Also, as you enter breeding season, monitor heifers‚ level of feed consumption or grazing. While body-condition scores may remain stable, any changes such as heifers going off feed as they're moved to drylot or heifers moving to pastures where forage is of poorer quality compared to where they were before can negatively impact ovulation. Research at Oklahoma State University shows that restricted nutrient intake for 14 days prevented ovulation in beef heifers without altering body condition. Therefore, heifers should be managed to avoid short-term nutrient restriction to maintain normal estrous cycles, says Dr. Selk.
Estrous synchronization is a part of most AI programs, and there are a number of protocols you can follow with different costs. You need to evaluate each protocol and determine potential benefits in your production system. Doug Zaleskey and Ryon Walker at Colorado State University San Juan Basin Research Center presented a report on cost and benefits of different estrous synchronization systems at the Range Beef Cow Symposium last December (see chart) based on research from various studies over the years.
Different methods work better on different types of animals, for instance heifers versus cows. So know what group you're synchronizing, then do your research into which method might work best. This may seem intimidating, but you can consult your AI service representative or your state extension service and discuss options with the reproduction specialist.
Iowa State University also offers a synchronization planner on their beef center Web site that allows you to plug in the numbers for the various methods and helps you walk through different strategies and cost. You can access that information at www.iowabeefcenter.org/synchplanner/synchplanner.asp