Planning Introductions
Cows are best induced when 9-12 weeks from their natural calving date. To acheive this the most important information needed is when the cow is due to calve. The most accurate method available for knowing when a cow is going to calve is manual rectal palpation. See the Pregnancy Testing page for more information.
Due to the limitations of late gestation preg testing the later the pregnancy testing is done, the harder it is to accurately age the foetus and we are forced to leave inducing cows until we are happy they will respond favourably. This may be only 4-6 weeks before they are due.
These cows may take more than a week to respond to the injection and calve, and are therefore only calving 3-5 weeks before they were due. If the cow has a post calving infection her cycling may be delayed and the end result is she will again be late next season.
There is little if anything gained in this situation. If these cows were identified earlier and the induction planned to occur 9-12 weeks before the due date, the maximum benefit of inductions can be realised.
Induced cows should have a dry period of at least 7 weeks. The condition of induced cows at the time of induction is critical to the success of the program. Cows gain condition easier when lactating, it is easier to feed concentrates at milking time and grain is cheaper than hay on a dollar per energy ratio. In some situations it may be best to delay drying off to get cows in appropriate condition for inducing. This will also delay inductions.