InCalf Program Set to Tackle Low Fertility in NZ Herds

By Barry Easton, Autumn 2008

The InCalf programme developed in Australia from 2003, is being adapted for New Zealand dairy farmers.

Mark Blackwell, the project manager for InCalf New Zealand, says the programme comes in response to an observed decline in the reproductive performance of the New Zealand dairy herd over the last 15 years.

There are no apologies for adopting the Australian model, which he says, translates well to the New Zealand situation.

 “The original (Australian) InCalf project was the most comprehensive study of commercial dairy farms of its kind in the world,” he says.

 “It was influenced by New Zealand so it is not as if it was something they stole a march on.

Adapted to NZ Conditions

 “In adapting InCalf for New Zealand conditions, we have adopted a policy of minimal change because we recognised that the Australians had done a really good job.

 “We found that we could pick up 90% of the Australian project. The changes for the New Zealand project include different targets because we are actually aiming to achieve higher reproductive performance targets.

 “A lot of the Australian feeding systems are based on feeding a lot more grain and supplementary feeding. They have dairy cows in tropical environments and herds which calve all year round in those sorts of environments. We have largely discarded year round calving. While we recognise that split calving is occurring in New Zealand to a small degree, whatever applies to seasonal calving also applies to split calving.”

Essentially InCalf is trying to help farmers achieve the weight-for-age targets that are established in the industry for the different animal types in terms of their liveweight breeding values, says Mark Blackwell.

 “What we are saying to farmers is that it is unlikely that they can solve all of the problems on their own and that they need to look at opportunities whether these are to feed their dairy cows or to feed their calves better in order to achieve those targets,” he says.

 “If dairy farmers are unable to monitor and achieve liveweight targets for heifers, then they should consider contracting them out to a reputable grazier who can do the job.”

No Single Factor

There is no single factor which can be attributed to low herd fertility in New Zealand, says Mark Blackwell. There are multiple reasons.

“That’s why it’s such a challenge to grapple with, because it is a multi-factorial thing going on,” he says.

 “There are a number of ingredients in the herd fertility cake. InCalf describes how the Australians have seven ingredients in the herd fertility cake, and we have eight.

 “In order to determine any single factor causing low herd fertility you would probably need to go to an individual herd situation.

 “For example, it could be a heat detection problem in a herd and that might be the single most important factor to address in that particular herd. In the herd next door it may be a totally different factor such as nutrition.

 “Genetics are a contributor to the level of performance, and possibly this is one of the factors which have contributed to the decline in performance in New Zealand over the last decade.

Replacements Grown to Size

 “Then there is the issue of replacements being grown to sufficient size. This is well known as a contributor to the fertility of heifers at puberty. Liveweight is a major contributor to this so heifers need to reach a certain bar to get to puberty. This determines when they calve in their first year and so on.

 “A heifer with an expected mature cow liveweight of 500kg should reach 30% of this target (150kg) at six months, 60% (300 kg) at 15 months and 90% (450 kg) at 22 months.”

Many Stakeholders

New Zealand’s InCalf project, says Mark Blackwell, is being aimed primarily at this country’s dairy farmers while at the same time recognising that there are a lot of other “stake holders” in the herd fertility area. Veterinarians, farm consultants, herd improvement field staff, those involved in pregnancy testing and graziers all fall into this category.

 “It’s not something focused solely at dairy farmers,” he says.

 “Even though it is written for New Zealand dairy farmers it is equally relevant to the people who are advising them and providing products and services to farmers.”

If the InCalf programme achieves its targets, says Mark Blackwell, the numbers of carry-over cows will diminish within the New Zealand herd.

“Carry-over cows are an option used to avoid the cost of culling a cow,” he says.

 “There will always be some animals which are empty, but farmers want fewer of them! There’s no point having a third of your herd not in calf and having to re-cycle a whole lot of cows. It’s extremely expensive to the farmer.

 “Our whole focus is to improve the in-calf rate at six weeks, which is two oestrous cycles into the mating. It is a point where the relative performance of different herds is actually most evident.

 “After 12 weeks, 15 weeks, or 18 weeks, the relative performance of herds is much harder to identify whereas at six weeks it is pretty clear who has done well and who has not!

 “The percentage of cows which remain empty is a bi-product of this. If we get the six week in-calf rate up, the empty rate will hopefully come down and then a number of things will happen. The number of cows which will need to be re-cycled as empties will reduce and we will have voluntary culling instead of culling by compulsion.”

While the likes of sexed semen is seen as being technologically very interesting and exciting it wasn’t a considered as an influencing factor for the New Zealand InCalf programme, says Mark Blackwell.

 “Sexed semen is not going to be any damn good if you can’t pick cows on heat!” he suggests.

 “This is fundamental stuff which a lot of farmers still struggle with, especially in large herd situations where there are young staff.”

 “The thing about InCalf is that it firstly asks the farmer where he is in terms of his herd. It is like those farmers who don’t weigh their yearlings, and as a result, they don’t know the starting point for their herd.

A Series of Steps

 “InCalf offers a series of steps, with step one being for the farmer to find out where he is at. Step two asks him to determine those areas in which he needs to improve, and these are weighed up using indicators and other tools, depending on professional help.”