by Malcolm Ellis, LIC bull Acquisition Manager.
The economic climate of the dairy industry is causing farmers to ask searching questions.
A number of those questions are about farm systems, as management seeks a farm set up that is sustainable and possesses adequate insulation in a world of fluctuating milk returns.
For many years a small portion of New Zealand dairy farmers have opted for a year-round, once-a-day (OAD), milking regime in their dairy farm operation. The motivation typically varies from lifestyle to long walks between paddocks and the dairy (due to farm layout). In some cases, cow shed design, or labour structure, contributes to the decision.
The industry is now experiencing a sharp increase in the practice of OAD milking, and a new motivation appears to be a desire to reposition the farm business. The decision to go OAD has been made easier by numerous examples within the industry of outstanding OAD farmers.
With my work in this space at LIC, I’ve had the pleasure of meeting a number of these successful OAD farmers. Once they are four to six years into their OAD journey, they frequently display an ability to produce very similar milksolids output from their farms as they would under a twice-a-day regime.
Cows may not peak as high as they once did, nor record the same per-cow per-day performance at different stages of the lactation, but the majority of extra productivity comes from days-in-milk. Some of the farms I’ve seen achieve an 80+% 6 week in-calf rate, and 4% to 7% empty rates. Put these statistics into the mix of the farm business and the impact of OAD is looking altogether positive and compelling.
LIC’s new OAD Selection Index (OADSI)
For the past 10 years LIC has operated an OAD index, with calculations largely aligned to the-then small amount of OAD herd performance data to the much larger twice-a-day (TAD) data sets. The upshot of the maths was a set of predictions for OAD breeding values.
In June 2015 the above method at LIC was overhauled. After considerable consultation with the OAD community, LIC identified non-negotiable functional OAD traits that were essential to reducing wastage in OAD regimes.
Udder support, front teat placement, milking speed, and body capacity are critical success factors in an OAD cow; these traits acknowledge the key differences, and challenges, between OAD and TAD herds. The four traits ultimately dictate survival of a cow in an OAD herd and require a weighting within the new desired gains OAD Selection Index – and potentially in place of the Residual Survival weighting within BW.
On the flipside, fertility – which has a current weighting of 15% in BW – is much less of an issue to an OAD farmer (with the regime going a long way to drive fertility improvement on farm).The weighting for the somatic cell count (SCC) trait has been an interesting discussion point. There is a common, misunderstood, perception that SCC can be an issue particular to OAD milking. Unfortunately, this opinion frequently comes from TAD farmers who have negative experiences brought about from putting their herd onto OAD late in a dry season (when there appears to be few other options); this can result in a bulk count doubling and running into the grading zone.
The majority of the OAD farmers I have met admit they must be vigilant with mastitis, treating and culling appropriately. However, if best practice is observed, bulk counts are kept under good control. A statistic that supports this, and really blows me away, is that the average SCC for OAD farmers (supplying milk to Fonterra) is actually lower than TAD counterparts across the season.
We wanted the new OAD selection index (OADSI) to be strongly correlated to BW, because at the end of the day BW is an outstanding predictor of productive efficiency. However, with the added pressure of only extracting milk once a day, OAD cows need to last.
The following weightings for OADSI were settled on:
When the breeding values (BVs) of these traits are calculated for bulls (or cows) it re-ranks some animals noticeably. However, the range of numbers is similar to BW: To make the number distinctly different, we simply add 1000 to the OADSI to avoid any possible misunderstanding of the two numbers.
This year LIC will offer a team of OAD bulls for each breed selected on the OADSI. The OAD bulls are outlined in the Alpha Catalogue at a reduced price, but come as a ‘no-choice OAD Pack’. Bulls will remain competitive on BW but will have the added advantage of being outstanding across the additional traits.
The decision to convert a farm system to OAD is not as simple as ‘just not getting the girls in tonight’. The breeding of the best cows to perform on OAD is a long game. Many will convert extremely well, but some don’t, and some won’t last.
The new OADSI will be a valuable tool in driving the rate of genetic gain in OAD herds as a result of driving down herd wastage. For the most up to date OADSI values, see the Alpha Sires page on our website.
Matt and Emma Dark of Aria, making a real success of OAD in a challenging farm situation, discuss the use of LIC’s new OAD selection index with Malcolm Ellis