The head of dairy research at Teagasc spoke at the Australasian Dairy Science Symposium late last year about the best standoff structures to complement pasture systems.
The high rainfall in Ireland and minimal grass growth during winter months meant cows had to be off paddocks for two to three months, he said.
The climate was similar to Southland where housing cows indoors for warmth purposes was no longer considered essential.
During the past 15 years the predominant wintering system in Ireland was free-stall cubicle barns, but uncovered free-stall systems had become more popular in recent years.
The main challenge to taking cows off pasture for long periods of time was to ensure cows could be fed and had enough space and a suitable surface to lie down in comfort.
Cows housed indoors on slatted floors were often under stress because they didn’t have enough space.
If there was adequate space and comfortable surfaces for animals, different wintering systems had little impact on cow performance, he said.
A two-year study at Moorepark compared four groups of 50 cows, one group in a traditional free-stall barn, the others in a covered and an uncovered woodchip surface with concrete feedpads alongside, and a woodchip surface where silage was fed directly.
The study showed no significant difference in cow liveweight or body condition score. Cows without cover outside didn’t need to be fed more to maintain body condition. Those cows did lose more heat, but didn’t increase their drymatter intake because the digestion of feed exceeded the heat lost to the environment.
From an animal welfare perspective there was little difference. For example, there were a similar number of mastitis cases in the different groups of cows. The only difference was the cows outdoors had a general sensitivity to lameness when they came back into milk. This was probably because their hooves had became soft from constantly being wet during winter and they had to get used to walking on hard surfaces again, French said.
Positive findings from various studies in Ireland found cows outside during winter had better milk production in the first few months of lactation – between 10 and 15kg milksolids (MS) extra.
“They adapted much faster to the outdoor environment. They also had bigger calves.”
The most important thing when discussing off-pasture systems was maintaining the proportion of grass in the diet, he said.
The Irish dairy industry planned to grow its milk production another 50% by 2020 once the European Union milk quota was lifted in April and maximising pasture intake was key to that.
Ireland’s milk production was on par with New Zealand’s before the quota was implemented 30 years ago, but had been unable to match it since, currently producing 400 million tonnes milksolids a year.
The crash of global milk prices was a reminder of how important the low-cost pasture system was for Ireland and NZ to remain competitive, he said.
