Synchrony programs form an integral component of successful reproductive management in the modern dairy herd. Synchronisation involves the management of the cow oestrus cycle so that a cow may be bred in a controlled and planned manner.
SYNCHRONISING COWS CAN HAVE MANY ADVANTAGES INCLUDING: EASIER HEAT DETECTION
Simultaneous display of heat by many cows enables easier detection of cows showing subtle or weak signs of oestrous. Heat detection aids such as scratchies, Kamars and tail paint tend to be more reliable when many cows are showing heat at the same time.
NB- Some synchrony programs have a fixed time for insemination and do not require heat detection for the first insemination. However, good heat detection after the initial insemination can be a critical factor to achieve overall good herd fertility. Good observation and application of heat detection aids are important for the full duration of the AI period.
EARLIER DETECTION OF NON-CYCLING COWS
Detection of heat earlier in the AI period allows those cows which are not cycling to be identified and therefore treated earlier. Pre-mating heat detection can also work well for some herds. Regardless, all cows that have not displayed a heat by day 21 into the mating period should be vet-checked. Delaying examination of these animals will cost more money in the long-term.
TIGHTER CALVING PATTERN
Breeding more cows over a shorter time frame can help tighten the calving pattern. The earlier cows calve, the more likely they are to get back in calf at the subsequent mating period. An increased number of earlier calving cows also increases milk production early in the season.
MORE HEIFER CALVES BORN EARLY
Early-born heifers have the advantage over later-born heifers in that they are more likely to achieve target weights for joining. Having a good replacement rate of heifers allows a greater ability to selectively cull cows with problems.
EFFICIENT USE OF LABOUR
On many farms, having a tight calving pattern allows more efficient use of labour and better observation of calving cows. Transition feeding is also easier to organise with groups of cows calving at a similar time.
ALLOWS USE OF ARTIFICIAL BREEDING IN HEIFERS
Synchronising heifers can also be advantageous:
- Early calving heifers (sometimes 2 weeks before the cows) can improve reproductive performance at the next mating period.
- Decreased number of bulls required.
- Increased genetic gain by using sexed semen.
- Efficient use of time and labour. Synchronising allows you to efficiently plan when you will treat and AI heifers without the need for constant heat detection. This is useful when heifers are not close to the dairy.
WHY NOT SYNCHRONISE?
Synchronising cows or heifers is not a magic cure for an extended calving pattern. Synchronising may be part of the solution to the problem, but there are many other aspects to consider. Synchronising alone is unlikely to help if:
- Cows are only recently calved.
- Cows are in extremely poor condition and are not cycling.
- Heifers are poorly grown and are significantly below target weight.
- There are limited resources to handle a large number of cows and heifers calving over a short time next year.
