Stay Proactive with Your Dairy Reproductive Program
Not long after a cow calves, the clock begins to tick on when that animal should be bred again. According to Donna Amaral-Philips, dairy professor at the University of Kentucky, timely pregnancies have a positive impact on the performance and profitability of dairy cows, not only during this lactation, but as importantly, their next lactation.
“Cows that do not become pregnant in a timely manner spend more time in later lactation as revealed by longer days in milk and longer calving intervals,” Amaral-Philips notes. “During later lactation, milk production is lower than in early lactation, especially in second lactation and greater cows. Dairy cows with long days in milk also are more likely to be culled, or if retained, go dry and calve over-conditioned. These over-conditioned cows often times have a higher incidence of health issues after calving, lower fertility and higher early pregnancy losses the next lactation. Thus, continuing this unproductive and vicious cycle.”
To keep an efficient and profitable reproductive program humming, proactive reproductive management practices need to be practiced daily. Some key areas to evaluate to see if you are achieving a proactive reproductive system include the voluntary waiting period, heat detection rate, conception rate and pregnancy rate.
Voluntary Waiting Period
Within a few short weeks after calving, an animal will already begin to show signs of estrus. However, just because she is showing signs of heat does not mean she needs to be bred. Generally, most farms start breeding cows an average of 60 days post calving. This may vary depending on the lactation stage. First-calf heifers might benefit from a slightly longer voluntary waiting period since their milk production is more persistent than mature cows, Amaral-Philips notes. The majority of cows should become pregnant by the 130 to 150 days in milk to help prevent cows from becoming over conditioned and minimize health issues.
“Fertility is slightly higher with a slightly later voluntary waiting period, especially with first-calf heifers. However, the magnitude and whether these differences are real depends on lactation number, method of insemination, season, milk production, and voluntary waiting period used,” Amaral-Philips says. “When utilizing a planned longer voluntary waiting period, the reproductive management program needs to be even more tightly managed to achieve a goal of having the majority of cows pregnant by 130 to 150 days in milk.”
Heat Detection Rate
Heat detection rate, also known as the insemination rate, refers to the number of cows that have been detected in heat and bred versus the number that are eligible to be bred within a 21-day period or other defined period. According to Amaral-Philips, the difference between heat detection rate and insemination rate is that heat detection rate also includes cows which are detected in heat but are not bred.
For most operations, a good target to shoot for is to have more than 60-65% of cows who are eligible to be bred inseminated within a 21-day interval or other defined interval. If this target is not being met, Amaral-Philips recommends evaluating these areas:
- Are you reporting all services for cows bred during this reporting period?
- Are you detecting cows in heat?
- According to Amaral-Philips, cows should be observed for signs of standing heat 3 times daily for 20 to 30 minutes each time.
- Check to make sure visual heat detection aids such as tail paint are replaced frequently to ensure proper performance.
- When using an activity monitoring system, be sure those using the technology understand how to use and interpret the data.
- Are cows cycling?
- Management of cows pre- and post-freshening plays a critical role in getting cows rebred in a timely manner. Cows that lose body condition in the first 21 days in milk after calving have lower pregnancy rates compared to cows who either maintained or gained body condition during this time frame.
Conception rate can be defined as the percentage of cows who conceive after being bred. However, this measure of fertility does not account for pregnancy losses between 30 to 60 days bred since cows are checked pregnant around 30 days. For most operations, a good goal to shoot for is having 45-55% of cows bred pregnant within a 21 or 30 day period. Areas to evaluate include:
- Reviewing semen handling procedures.
- Ensuring semen is being deposited into the uterine body (no more than 1 inch beyond the cervix) and not into a uterine horn.
- Cows are being inseminated at the proper time after standing heat or 14 to 18 hours post the last GnRH injection as part of a timed AI program.
- Vaccines to prevent reproductive diseases have been given, administered as directed, and follow the guidance of your veterinarian, timing of administration, and type of vaccine needed.
- Heat abatement practices are in place.
In comparison to the conception rate, pregnancy rate is the percentage of cows who are pregnant within a 21-day or month in relation to the total number of cows in the breeding herd. This value reflects the success rate of getting cows pregnant.
According to Amaral-Philips, a good percentage to aim for is 26% or greater. “Improvements in pregnancy rates increase profit. When pregnancy rates are around 15%, an insufficient number of heifers are born yearly to serve as replacements for the dairy herd. Generally speaking, pregnancy rates need to be around 20% to produce enough replacement heifers,” she notes.
If pregnancy rates fall below this target, some areas to evaluate include:
- Timely open cow checks – not pregnancy checks – are done routinely to identify open cows 30+ days post breeding.
- Pregnancies should be reconfirmed after 60 days pregnant to account for early pregnancy losses.
- Since pregnancy rate is a function of heat detection, insemination and conception rates, management practices associated with these areas impact this reproductive benchmark.
For a reproductive program to operate at peak performance, it’s important to ensure proper management practices are being followed routinely and that benchmarks are put in place.
“Unfortunately, parameters such as calving interval, average days open, and number of cows culled for reproductive reasons are more historical and do not reflect current performance within the current breeding program,” Amaral-Philips says. “These benchmarks are important since they will impact the overall performance and profitability of the herd but are not as helpful in managing the successes and shortcomings of the current and on-going breeding program.”