There is renewed interest in synchrony programmes for breeding dairy cows and heifers this season. The objective of any synchrony programme is to get more cows in calf earlier in the season and with less effort.

However, not all synchrony programmes achieve this for a variety of reasons so it’s important to keep that in mind before jumping headfirst into a new programme.

All synchrony programmes introduce hormones to the cow that will alter the timing of her natural reproductive cycle

In most cases, putting more effort into making sure cows are in the right body condition score, breeding cows with good fertility and improving heat detection techniques would make a much greater difference to the six-week calving rate for less effort and at a far lower cost than any synchrony programme.

All synchrony programmes introduce hormones to the cow that will alter the timing of her natural reproductive cycle.

Prostaglandin (PG) and progesterone (PRID/CIDR) are the two main hormones involved but depending on the type of programme being adopted, secondary hormones such as GnRH (Receptal, etc) are often used in fixed-time AI protocols.

Hormone treatment will help to cure these issues much faster than if left to their own devices

There are two instances where synchrony programmes are used on dairy farms. The first is to treat problem cows. These are cows that are not cycling, cystic or are dirty.

Hormone treatment will help to cure these issues much faster than if left to their own devices. The vet will be able to determine which treatment is best for each issue.

The second way it is used is to adjust the timing of otherwise normal and healthy cycles.

The aim here is to get as many animals as possible submitted in the first three weeks. The following protocols are designed with this in mind.

Why-Wait programme

Kilkenny-born but New Zealand-based dairy farmer Enda Hawe spent 17 hours talking to over 150 Irish dairy farmers in seven discussion group video conference meetings last week. The meetings were arranged by dairy consultant Matt Ryan, with the purpose of motivating his groups for the upcoming breeding season.

Enda is excellent at breeding, achieving a 6% empty rate after 11 weeks of breeding with all AI. He uses the Why-Wait PG-based programme as outlined in Table 1 on the opposite page.

The programme involves moving cows that would ordinarily come in heat in week two to come in heat in week one and moving cows that would ordinarily come in heat in week three to come in heat in week two. Effectively, this programme condenses three weeks of breeding into two.

The objective is to get extra days in milk the following spring because a higher proportion of the herd will be calving earlier.

The programme is only possible if pre-breeding heat detection is carried out

Furthermore, because more cows calve earlier they will have more time between calving and breeding in the following year, so compact calving should compound fertility improvements.

The programme is only possible if pre-breeding heat detection is carried out. Enda paints cows a different colour depending on when they cycle pre-breeding.

He then scans cows between 28 and 35 days post-service and will use PG to short-cycle a cow if she is not in-calf at that scanning as she is most likely to be a missed heat.

Enda Hawe speaking to the Greenshoots discussion group via Zoom last week.

Enda places a huge emphasis on record-keeping and heat detection, with all staff on the farm trained to recognise the signs of heat. One shot of PG costs in the region of €5.40 per cow.

Fixed-time AI

Fixed-time AI (FTAI) synchrony programmes do away with the requirement for any heat detection. There are many different variations of FTAI programmes available for both cows and heifers.

Common FTAI programmes are outlined on page 50. A full FTAI programme will cost in the region of €26/animal.

Heifers

The most common type of synchrony programme for heifers is to give a shot of PG to heifers not served six or seven days into the breeding season.

A double PG programme involves giving all heifers a shot of PG 13 days before the start of breeding. Another shot of PG is given two days before the start of breeding and heat detection aids are applied.

The majority of the heifers should come bulling in the first three days of the breeding season.

However, for PG to work on heifers, they must be cycling. If they are underweight and not cycling, the PG won’t have any response.

Comment

In my view, there are only two classes of stock that a synchrony programme should be considered for. These are non-cycling or problem cows and maiden heifers. I’m not at all convinced of the merits of synchrony programmes for widespread use across a herd.

Firstly, CIDR-based programmes override natural selection because they present cows for AI that would otherwise not be presented until later in the season, if at all.

Extra days in milk is often used as a counter-balance to the cost of a synchrony programme and that is true

Breeding replacements from these cows is passing on their bad traits to the next generation of cows coming into the herd. This is less of an issue with PG-based programmes as they only work on cows that are already cycling.

The next issue I have with it is the cost. Extra days in milk is often used as a counter-balance to the cost of a synchrony programme and that is true.

However, the question should be asked at what stage is that extra milk going to come at? How many already high-performing dairy farms have spare grass in February or March? If the mean calving date is brought earlier because more cows calve earlier, it will have a big impact on the feed budget.

There is a risk that a lot of the extra gain from days in milk could be undone by higher feed costs or having to delay mating start date, which would be counterproductive.

Some farmers get on very well and achieve good results, while others achieve what I would consider poor results

The other thing to be aware of with all synchrony programmes is the level of risk and workload involved.

Some farmers get on very well and achieve good results, while others achieve what I would consider poor results even though they supposedly follow the same procedure.

There are of course a lot of factors involved but a synchrony programme isn’t a magic bullet to get cows in calf.

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