Cattle: Plan artificial insemination protocols now
Artificial insemination has the potential to increase calf crop uniformity and weaning weight, reduce birth weight and calving difficulty, shorten the calving season and even produce calves of a known sex.
However, less than 8 percent of U.S. beef operations have incorporated artificial insemination (AI) as a routine management strategy, according to Carl Dahlen, North Dakota State University Extension Service beef cattle specialist.
“In recent years, estrous synchronization protocols have been developed that address producer concerns about lack of time and labor, complicated synchronization protocols and cost,” he said.
“Reliable protocols successfully synchronize estrous cycles of cows cycling at the beginning of the breeding season and those that are not, which are up to 60 percent of cows,” he added. “These protocols also offer options that rely on heat detection, use fixed-time AI to eliminate heat detection or use a period of heat detection followed by a fixed-time AI.”
Factors that determine the success of an AI breeding season are:
• Body condition score: It serves as an indicator of overall nutritional status.
Ideally, cows would be in adequate body condition (score of 5 to 6 on a 9-point scale). Cows with inadequate or excess body condition will have difficulty becoming pregnant, and increasing the body condition of thin cows after calving is very difficult because of the high nutrient requirements of lactation and high feed costs.
• Days postpartum: After calving, every cow must go through a period of uterine repair and recovery before resuming normal estrous cycles. The suckling stimulus from calves increases the amount of time required for cows to start cycling after calving. To have success with AI protocols, cows should be at least 45 to 50 days postpartum at the time of breeding.
• Ability to work cows: Synchronization protocols may require producers to work cows up to three times. From experience with vaccinating or pregnancy checking cows, producers know how well their herd moves through their working facilities.
Producers always should practice calm, low-stress handling techniques through adequate facilities because stress may lead to poor results.
• Heat detection efficiency: Producers wishing to use protocols that include heat detection must identify cows that are in heat. Not catching cows that come into heat will lead to disappointing results.
• Proper semen handling and insemination technique: Proper semen handling begins when the semen arrives on the ranch. Transfer semen from dry shippers to storage tanks as soon as possible, and make sure the tanks have plenty of nitrogen and are kept in a safe place. Thawing semen, loading AI guns and insemination all need to be done correctly. Producers wishing to AI their cows should be proficient at AI or consider hiring an AI technician.
• Recordkeeping: Good records allow producers to know how many days have passed since a cow calved, whether a cow had problems calving, breeding dates, service sires, any other observations at breeding time and predicted calving dates.
• Weather: Adverse weather stresses cattle and can contribute to poor results.
“Plan ahead to make sure you have all of the products needed for estrus synchronization,” Dahlen advised.
The Estrus Synchronization Planner is a Microsoft Excel-based spreadsheet program available free of charge at http://www.iowabeefcenter.org/estrus_synch.html to aid in protocol selection and evaluation.
This program allows producers to enter their desired breeding dates, review available protocols, compare total input costs of the different systems and select the protocol appropriate for their operation. After selecting a protocol, the program develops barn sheets and a monthly calendar that describes the timing of injections and melengestrol acetate feeding or controlled internal drug release insertions.
Other resources, including information on specific synchronization protocols and cattle reproduction, can be found at http://beefrepro.unl.edu/resources.html.
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