Replacement Heifers are Essential
Farmer should have a good replacement heifer ready to take a cow’s place when it is time to be sold.
Acquiring or raising high quality replacement heifers is an essential and major investment for the cow-calf producer. The replacement heifer becomes the genetic building block for the cow herd. The producer hopes that a replacement heifer will become a fertile cow that produces a calf, annually, for a long time.
But, Avoid Herd Imbalance
There are very few situations when an open stall is preferable to an occupied stall or vice-versa. Such an imbalance can lead to suboptimal cow sale decisions, choke cash flows, destabilise manpower, put pressure on infrastructure, have adverse impact on herd growth, and lower herd profitability.
The dairy needs enough animals in each age group to ensure that future sale decisions are not constrained by a lack of available replacements. Heifer inventory management must take into consideration long and short to medium-term planning steps so that a dairy can meet their goals.
Two Important Questions – How Many To Retain? Which All To Retain?
Managing Heifer inventory is a delicate balance. Farmers prefer having animals at the ready, so appropriate cow-sale decisions can be made. But keeping extra inventory around is expensive. So the question is how many, and which all replacement heifers to retain in inventory?
How Many Replacement Heifers to Retain?
Not all heifers that grow at the farm need to be milked at the farm. Only those carefully chosen should continue at the farm. Keeping in mind the potential threats to animal health and to the business, to decide on how many Replacement Heifers to retain the farmer needs to ask himself these broad questions:
- How many animals am I going to need in the future?
- How many animals can my farm accommodate in the future?
- What are my liquidity needs?
- How much minimum and maximum milk do I need?
Which All Replacement Heifers To Retain?
Deciding which all to retain a complex cookie to crack.
- Target parentage – A thorough evaluation of mature females in a herd may identify cows from which we simply don’t want to keep calves. Cows or cow families that are overly aggressive, have a history of heavy calves or calving difficulty, or are too large, too small or otherwise do not match our vision of a structurally sound cow, may be good candidates to sell.
- Have a vision of your ideal herd – Every farmer has the image of his ideal cow and herd. These ideals can vary based on who you ask. This could set the parameters outside of which you may want to sell.
- Keep older heifers – Early-born heifers are older and often heavier at weaning, compared with their later-born contemporaries. Early-born heifers also have a greater chance of becoming pregnant earlier than later-born herd mates.
- Sell female twins to male calves – Females born twin to a male calf have higher probability of infertility and should automatically be sold from the replacement group.
- Evaluate growth performance/ heifer size – Some farmers use the growth rate from birth to weaning, or from weaning to a yearling age, as a selection criteria. The same selection pressure likely is used, indirectly, if the biggest heifers are selected at any given time point. You must use caution with this selection criteria to stay away from selecting extremes that have potential to move mature weights away from your ideal.
- Study the genetic potential viz pedigree or genomics – Heifers may look alike and meet all other selection criteria; genetic potential can be used to narrow the replacement pool to a target number. Consider using traits that are of high value to cow herd profitability.
- Reproductive tract scores/pelvic measurements – About 45 days before the breeding season, a veterinarian can evaluate the reproductive tract and pelvic measurements of the heifers, assigning a score of 1 to 5. This test can help identify heifers with narrow pelvic areas that might go on to have calving difficulty.
- Select to achieve early pregnancy – Selecting only heifers that become pregnant early can have major impacts on herd reproductive rate and productivity. Heifers becoming pregnant early have greater longevity and wean more and heavier calves, compared with heifers becoming pregnant later in the breeding season.