To date, research work, such as that undertaken at Ballydague, has only involved small numbers of cows. Such trials are expensive to carry out and cow numbers are a constant battle. However, the results are evaluated from a statistical point of view and stand up internationally. Larger sets of data would help to propel the argument to a new level.
One such large Irish study, published in the Journal of the American Dairy Science Association, looked at the milk production and fertility performance of Holstein, Friesian and purebred Jerseys and their respective crosses in 40 Irish spring-calving commercial dairy herds from the years 2008 to 2012 inclusive. For the purposes of the study, a total of 24,279 lactations from 11,808 cows were examined.
The results from this study were again along expected lines. Milk yield per cow was greatest for the Holstein (4,965 litres), intermediate for the Friesians (4,458 litres), and least for the Jerseys (4,099 litres).
In percentage terms, the Holsteins were 12pc ahead of the Friesian and 19pc ahead of the Jerseys. However, the milk constituents were highest for the Jersey (9.38pc), intermediate for the Friesian (7.91pc), and least for the Holstein (7.75pc).
The table (left) tells you all you need to know about the benefits of crossbreeding from a cow-yield point of view. The Holstein-Jersey cross cows produced 256 litres extra milk volume over the average of the two parent breeds. This extra milk also had higher constituents. In fact, the Holstein-Jersey cross cows produced 425kg of milk solids, 21kgs more than the Holstein, 30kgs more than the Jersey, and 64kgs more than the Friesian.
The extra kick in volume is explained by heterosis. Heterosis or hybrid vigour means that crossbred animals usually perform better than the average for the two parent breeds.
What of the reproductive performance from the study?
As we know, reproductive performance is fundamental to the profitability of seasonal calving systems. It is underpinned by the ability of cows to resume cyclicity earlier post-calving, express estrus, conceive, and both establish and maintain pregnancy.
Crossbreeding has been proposed as a method to rapidly reverse the decline in reproductive performance that occurred due to the 'Holsteinisation' of the dairy herd.
Back to the reproductive performance of the cows in the study. The Holstein-Jersey cows calved 12 days earlier as heifers compared to the average for the parent breeds.
This result is consistent with previous research which demonstrated superior reproductive performance in crossbred cows relative to their parental purebreds, including a 22pc greater in-calf rate to first service, a 19pc greater in-calf rate at six weeks of breeding, and an 8pc greater in-calf rate after 13 weeks.
What are the overall economic implications of crossbreeding?
The ideal cow for future milk production in Ireland has been characterised as a robust, healthy, efficient, fertile, easy-care cow that produces a large quantity of high volume milk solids. The introduction of the A+B-C milk payments rewards milk solids production.
The economic benefit from superior milk production and reproductive performance in the study just described, equate to an additional €162 per cow per lactation relative to the parental breed average. For this economic analysis, a milk price of 31c per litre was assumed.
This additional profit is consistent with Frank Buckley's work in the Ballydague trial and is also consistent with previous economic analysis that attributed greater profitability to greater lifetime production, increased longevity, and lower replacement rates in crossbred herds, relative to their purebred contemporaries.
All the research work carried out to date indicates increased farm profit when the dairy farmer makes the decision to go the crossbred route.
However, dairy farmers continue to vote with their feet and cite reasons such as increased variation in crossbred stock, low calf and cull cow value as reasons for not going down this route.
Milk recording agencies can today put groups of animals in the same herd into different categories and any farmer with crossbred stock can see first-hand how these cows are doing relative to their peers on the farm.
This is real on-farm data that will enable the farmer to make an informed decision about the direction their breeding needs to go.
As stated, the numbers of farmers crossbreeding remains very low. Only 5pc of cows are classified as crossbred, and crossbred replacements are difficult to source. The 5pc figure equates to approximately 70,000 crossbred animals.
There is one fundamental point you should not ignore: If you are going the crossbreeding route, only select the highest EBI semen you can purchase.
John Donworth is recently retired from Teagasc and was a former dairy specialist and regional manager with the agency. email: firstname.lastname@example.org
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