Sucklers: is synchronising an option for breeding this spring?

Most suckler farmers are very aware of the increased benefits that can be obtained through AI. The primary benefit is, of course, access to a wide selection of proven, high-genetic merit sires and the ability to select these sires individually for each cow or heifer.

Other benefits include the eradication of carrying a stock bull on the farm for the year and the associated safety risks this animal brings.

Yet, despite these benefits, figures show that, in 2019, only 16% of beef calves born in Ireland were AI-sired.

Put off

The reality is that many more suckler farmers would like to use AI, but are put off by a combination of heat detection and/or the workload of bringing in cows and heifers on a daily basis.

Technology, such as the MooCall heat detection system, is making big strides in assisting farmers with heat detection, while a gradual improvement in farm infrastructure is helping somewhat with bringing in cows and heifers for service.

One less common option that can be used to help with both heat detection and animal handling is synchronisation.

Synchronising involves hormonally manipulating the female’s reproductive system to trigger oestrus and/or to determine when females should be inseminated.

Advantages

The obvious advantage of synchronisation is that it facilitates AI.

In fixed-time AI synchronisation programmes, all females can be served at the same time, but even in a standard synchronisation programme, it is possible to somewhat predict when females will be in heat. This obviously eliminates or reduces the need for heat detection in the first cycle.

With females’ heats essentially being grouped together, it also reduces the need for bringing animals into the yard daily during the breeding season, albeit they will have to be handled two to four extra times prior to breeding.

Beef cows are much slower than dairy cows to re-commence oestrous cycles after calving

Synchronisation can be used to induce heat in anoestrus cows. This is particularly useful to pull late-calving cows back into the main calving period.

Beef cows are much slower than dairy cows to recommence oestrous cycles after calving because of the bond between the cow and her calf. In many herds, 30% to 40% of beef cows will still be anoestrus (non-cyclic) at 60 days after calving. While the conception rate achieved at the induced heat is generally low (30% to 50%), fertility at subsequent repeat heats is normal (55% to 70%).

Some would argue over the following point being an advantage or disadvantage, but with groups of cows and heifers being served at the same time, they are also going to calve in or around the same time.

This can be an advantage during the calving season to organise labour, housing and calf management.

Disadvantages

The greatest disadvantage with synchronisation is the variability in conception rates. Conception rates to first service vary between 35% and 75%. A good target would be two-thirds (66%).

Combined with this is the prohibitive cost. A typical synchronisation programme can cost between €20 and €30 per animal, excluding AI costs and veterinary call-out costs if required.

Furthermore, synchronisation does not eliminate the need for heat detection completely. Cows that do not go in-calf to the first service must be detected in heat for the second service and re-inseminated.

Alternatively, a bull can be used to breed cows returning to service. It is worth noting that the repeats will come in 18 to 21 days after the first service, so they will be somewhat grouped.

Options

The options for cows and heifers vary greatly and should be discussed with your vet (most synchronisation drugs are prescription-only medicines) and your breeding adviser.

Some programmes will facilitate fixed-time AI, while others will require a period of observation to complement fixed-time serves.

These decisions will obviously affect costs, with simple heifer programmes being quite inexpensive and fixed-time programmes costing as much as €30/head.

The questions you need to ask are:

Once you have settled on a programme, be sure to ask your vet and/or breeding adviser to write out clearly the steps that you need to take and the exact times these need to be carried out. Some steps can be very specific, down to the hour even.

Tips for best results

Cows should have a moderate body condition score (BCS) of 2.5 to 3.0 at time of commencing the programme.

It is equally important that cows are a minimum of 35 days calved at the time of commencement and they are on a good plane of nutrition for a minimum of three to four weeks prior to, during and after treatment.

If grass quality is low, consider going with 1kg to 2kg in the 10 days prior to starting the programme and while the programme is ongoing.

Synchronisation should only be used in herds where the levels of management, and in particular heat detection skills, are high in order to detect heats - particularly repeat heats.

Alternatively, if you are not in a position to or do not feel confident detecting heats, a stock bull should be turned out with cows following the synchronised AI.

It is vitally important that high-fertility semen is used and the competence of the inseminator is high. Semen must be thawed carefully (15 seconds in water at 35°C) and inseminated into the cow within one to two minutes of thawing. Each straw should be thawed separately.