The Goal: First calvings by 24 months of age.
The Strategy: Begin planning for her to calve at 24 months the day she is born.
Getting a heifer to calf at 24 months of age starts the day she is born. Every step in your heifer rearing process from newborn, to weaning and on to breeding directly impacts the time it takes to get your heifers into the pipeline, and generating profits.
Reaching a 24 month calving age means the first breeding must occur at 13 months. A herd with an average heifer conception rate of 60% with good heat detection should start their breeding program at 13 months to ensure the majority of heifers are pregnant by 15 months, reaching the 24 month goal.
In order to have your heifers in top shape for breeding at 13 months, the first 12 months of her life are key. A heifer’s nutrition and health from the day of birth until she reaches the breeding group determines her breeding eligibility and her effectiveness in the breeding program. A general rule of thumb is that a heifer should be at 60% of her mature body weight when first breeding occurs.. The recommended weight for a breeding age Holstein heifer is approximately 395 kgs (870 lbs); the recommended height is 127 cm (50 inches). Subpar nutrition and disease in the first few months of life will greatly affect whether these growth targets are met.
If your heifers are not reaching these growth targets by the time breeding begins, it is better to alter management practices in order to reach these targets, rather than breeding later in life. Breeding her later will put her into the milking line later, keeping her on the wrong side of the ledgers.
Regularly identifying heifers to be moved into the breeding group is a challenge. Too often, the first mistake is not moving heifers into the breeding group in on time. Additionally, many dairymen fail to do regular pregnancy checks on heifers, leaving their reproductive status unknown. By not pregnancy checking heifers, open heifers may go unnoticed until they are past 15 months of age. A protocol should be established in which heifers are regularly moved into the breeding group and their pregnancy status is checked during every herd health. This data should be recorded and uploaded to Dairy Herd Management (DHI )during test days. DHI can also give you a list of heifers > 12 months of age on each test day which will keep you focussing on the heifers that need to be bred.
Sire selection is often overlooked as part of the heifer breeding program. With heifers having the best overall conception in the herd, and some of the newest genetics they provide a unique opportunity to maximize genetic gain at a low breeding cost. When choosing a sire for heifers, one item to pay particular attention to is calving ease. First lactation heifers are more likely to have calving difficulties, making the choice of a calving ease mating sire critical to the heifer as she begins her productive life and the resulting calf.
Herd sires are too commonly used on heifers in Ontario, as they’re seen as a low input to get heifers pregnant. Although it can appear to be an attractive financial option, there are many costs and risks associated with using a herd sire. A bull in the herd, removes the opportunity to optimize sire selection, possibly leading to higher inbreeding and less productive cows. Additionally, the all important calving ease becomes the great unknown; with A.I. sires, selection to reduce hard calvings is easy and reduces the associated losses. Many herds that use a herd sire end up having 35% or more of their herd resulting from natural service in a very short time.
Considering that the breeding program begins at 13 months of age and finishes by 15 months of age, there are only three estrous cycles to get your heifers pregnant. This makes estrous detection key to any breeding protocol. Proper visual heat detection involves watching your heifer for 30 minutes, twice a day. With heifers often “out of sight, out of mind,” this hour spend on heat detection is often not delivered in most herds.
Over the past decade, many tools have been developed to assist dairymen in overcoming some of these heat detection shortfalls. Electronic activity monitoring accuracy and cost effectiveness has improved over the past decade making it an attractive option for heifers. Using electronic activity monitoring can help bridge some of the heat detection gaps that commonly develop, by monitoring heifers on a 24 hour basis. As well, better estrous synchronization protocols have also been achieved, which can help to deal with non-cycling animals and problem breeders.
Monitoring is a critical and overlooked part of a heifer breeding program. In order to manage and focus our resources on the right parts of the breeding program, we need to monitor our results. As an industry, we need to start using pregnancy rate more effectively when talking about heifer reproduction. Although pregnancy rate is becoming the common measurement for assessing the performance of the lactating herd, it is still under-utilized when it comes to heifer reproduction. Remember, pregnancy rate answers two important questions: 1.Are your heifers getting bred? 2: Are they getting pregnant from those breedings? Your heifer reproductive performance can be summed up into this one number.
Other key numbers we should monitor in regards to heifers are age at first breeding, age at first calving, first service conception, overall conception and percentage of first lactation calvings that result in stillbirths. Monitoring these numbers will help you assess what is working well with your breeding, and will also help find opportunities for improvement.
