Significant commercial pressures have been identified within the New Zealand Thoroughbred and Standardbred breeding industries in a just-published scientific review of the country’s commercial equine production.
New Zealand’s Thoroughbred breeding industry is the sixth largest in the world, with the Standardbred breeding industry assessed as fifth largest.
Massey University researchers Erica Gee, Chris Rogers and Charlotte Bolwell included findings from 34 scientific papers in their 10-page industry review published in the journal Animal Production Science.
The Thoroughbred and Standardbred studbooks are the largest in New Zealand, both with well structured systems in place for recording breeding data.
The review team found there were about 70 commercial Thoroughbred stud farms in New Zealand, most concentrated in the Waikato and South Auckland regions of the North Island.
Stud farms in these regions tended to be larger and stood more stallions than those in other parts of the country.
In the 2014–2015 breeding season, 5424 Thoroughbred mares were bred, with 132 Thoroughbred stallions covering 10 or more mares.
They noted that, over the past decade, there had been a reduction in the number of private Thoroughbred stud farms and an increase in the size of the remaining operations.
“This change,” they said, “represents the altered economics of the Thoroughbred racing industry and the increased trade and use of shuttle stallions from the northern hemisphere.”
They said there were significant commercial pressures on both racehorse breeding industries, with declining broodmare numbers and increasingly large book sizes for popular stallions.
Commercial breeding farms in New Zealand were pasture-based, with high stocking rates during the breeding season, which fortunately coincided with a period of good pasture growth.
The breeding season for Thoroughbreds was very short, they noted, with a disparity between the official breeding season and the physiologic breeding season for mares.
These issues were confounded by variable gestation lengths in mares, making it difficult for them to maintain yearly foaling patterns.
However, the reproductive efficiency of Thoroughbred mares was improving, they said, mainly due to veterinary and stud management practices. As a result, more foals were being produced from fewer mares and sires.
The review team identified a bias towards breeding younger mares with high fertility in preference to older mares, unless the mares had desired genetics or successful offspring.
“Careful management of popular Thoroughbred stallions ensures that large books of mares can be covered by natural service,” they said.
“In contrast, Standardbred stallions are collected every-other-day using an artificial vagina, allowing the breeding of mares at distant locations by artificial insemination, using chilled or frozen semen.”
The researchers said there was limited data on the size and scope of Standardbred breeding farms and common management practices.
“The use of artificial insemination within this industry and the clustering of breeders, owners and trainers of racehorses is associated with many participants with smaller numbers of mares managed on their own property.”
Such a system encouraged the few larger farms to operate as stallion stations, focusing on the collection and distribution of semen.
They said an investigation into the feasibility of using artificial light on the country’s commercial studs to lengthen the breeding season and improve the outcomes for foals was warranted.
The authors also suggested New Zealand would benefit from having a centralised recording system for sport horses. Such a resource would improve understanding of the sport-horse breeding industry, they said.
“The lack of a well structured and universally recognised integrated registry for sport horses in New Zealand means that current numbers and distributions of sport-horse broodmares, sires and stud farms are not known.”
Estimates have suggested that there are about 4000 sport-horse broodmares, with 1000 foals born annually. An estimated 300 sires stand at stud.
The authors said breeding horses kept at pasture under New Zealand conditions required excellent stud management and veterinary management to achieve good outcomes.
The review is the first of three in a series exploring elements of commercial equine production in New Zealand.
Commercial equine production in New Zealand. 1. Reproduction and breeding
Erica K. Gee, Chris W. Rogers and Charlotte F. Bolwell.
Animal Production Science http://dx.doi.org/10.1071/AN16728