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by Mel DeJarnette,
Select Sires Reproduction Specialist

Prostaglandin based breeding programs are known by many names. "Controlled Breeding", "Target Breeding", and "Monday Morning Breeding" are the more popular names with which you may be familiar. Although known by many names, don't let that confuse you. The foundation of all these programs is a common basic principle which involves the systematic use of prostaglandins to improve reproductive efficiency in dairy herds.

PROSTAGLANDIN FUNCTION
Prostaglandin is a natural occurring hormone that plays an important part during a normal estrous cycle. Prostaglandin is released from the uterus every 21 days in cycling animals resulting in the initiation of a new heat cycle. Prostaglandin based breeding programs use our knowledge about the cow's natural cycle to gain control of her reproductive processes and time them to fit the management program.

THE BASIC SYSTEM
Groups of eligible cows are injected with a form of prostaglandin (Lutalyse, Estrumate, or Bovilene). There are four categories of eligible cows:

All open cows that are approaching or have just past the voluntary waiting period (VWP is 45-60 days following calving in most herds).

Cows not responding to a previous prostaglandin injection. (Animals not responding to three successive injections should be checked by the veterinarian for cyclicity.)

Inseminated animals that have been diagnosed open by palpation.

Early post-partum cows. Early post-partum injections have therapeutic benefits in helping cows with low-grade uterine infections to clean. Additionally, the more times a cow cycles before you breed her, the better the chance that she will conceive when she is inseminated. Prostaglandin given two weeks prior to the end of the VWP will also increase the percentage of animals in the proper stage of the cycle to respond at the first breeding injection.

INJECTION FREQUENCY
The frequency of injection will vary depending on your herd size and other management factors. Prostaglandin programs work by allowing you to systematically schedule reproductive management procedures into short time periods for "groups" of eligible cows. While large herds (> 400 cows) may have dozens of eligible cows each week, smaller herds (< 60 cows) may only have one or two eligible animals. Therefore, smaller herds may choose to inject groups of cows at two or three week intervals.

The key is to choose a specific day of the week for injections that will complement your labor availability for heat detection and breeding. Then, inject all eligible cows on the injection day regardless of the number of weeks since the previous injection. This facilitates simplicity and minimizes confusion.

Example 1. Farmer Jones has a 60 cow herd. He and his wife do most of the chores except for weekends when the kids are out of school. Because of the small size, this herd should probably only inject once every two weeks. Because more labor is available on weekends, injections should be given on Wednesdays (see figure below).

[Farmer Jones Chart]

Example 2. Farmer Smith has a herd of 400 milking animals and adequate hired labor during the week. In a herd this size, there would likely be 7 to 10 eligible animals available each week. Injections on Monday would allow most animals to respond and be inseminated prior to the weekend (see figure below).

[Farmer Smith Chart]

ADVANTAGES

IMPROVED HEAT DETECTION
A major benefit of prostaglandin programs is that it groups cows so they all come into heat at the same time. This facilitates more efficient use of labor for heat detection. Mounting activity also increases two-to-four fold with multiple cows in heat. Thus, not only can you focus time and labor to a period when cows should be in heat, but the cows are also more willing to display the many signs associated with estrus. This may be particularly important during the warm summer months when cows are harder to catch in heat.

REDUCED DAYS TO FIRST SERVICE
The more efficient you are at detecting heat, the greater the impact on "days to first service." But, prostaglandin programs also have a more direct impact. With a voluntary waiting period of 60 days between calving and breeding, the average days to first service would typically be around 70 days (if all cows cycled and were detected during that 21 day period). In a herd on a prostaglandin program, responding animals are generally inseminated three to four days after each injection. Thus, on average, days to first service are cut by about seven days for each responding animal.

POSSIBLE INCREASED CONCEPTION
Most herds on a prostaglandin program have enjoyed increased conception rates. Prostaglandin has no direct effect on fertility, however better heat detection results in fewer cows getting bred when they're not actually in heat.

FOCUS ON CYCLICITY
An organized prostaglandin programs "forces" you to focus more attention on the cyclicity of your herd. Any non cycling cow on the program will be diagnosed as a problem within two to three weeks of her VWP. You can then seek veterinary intervention early to get her back on track. Equally important is the fact that cows, that are cycling and healthy, get inseminated early. These are the cows that make money for an operation.

FLEXIBILITY
Some producers may limit the number of animals bred during the warm summer months. In the fall and winter, cows may be injected weekly and gradually back the program off to once every two weeks or three weeks as a higher percentage of the herd becomes pregnant. In the spring, a prostaglandin program can be used to get more animals pregnant before the summer breeding slump arrives.

PRECAUTIONS!


  1. Prostaglandin programs require accurate identification of cows and excellent record keeping systems to ensure that previously inseminated cows are not mistakenly injected with prostaglandin.

  2. Inseminate cows based on observation of standing estrus. Although many prostaglandin labels recommend breeding cows 80 hours after the injection, that's not conducive to optimum fertility.

  3. Although a prostaglandin program allows you to focus heat detection during a short period of time, some heat detection should be done every day to detect naturally cycling animals and possible returns to estrus of previously inseminated animals.


WORK WITH YOUR VET
Prostaglandin programs require a good relationship with your veterinarian. Prostaglandin is available by prescription only, and your veterinarian's help is critical in setting up a protocol that will work in your herd. Once the system is in place he will spend less time palpating cows that don't actually need to be palpated (cows that are cycling normally) and can spend more time on more important issues such as problem cows, herd health, nutrition, and management. What's more, your veterinarian's time is more efficiently utilized palpating cows for pregnancy as opposed to palpating them for cyclicity.

To order product contact:
Select Sires Inc., 11740 U.S. 42 North, Plain City, Ohio 43064 / Phone: (614) 873-4683 Fax: (614) 873-5751