Grass tetany cases confirmed in Cork with late-calving cows

Dairy farmers in East Cork are reporting cases of grass tetany, according to Teagasc regional manager Gerard MacMahon.

“Grass tetany is an unusual problem at at this time of the year,” he said.

“But the issue seems to be arising with late calving cows that are now in full milk. The first sign of grass tetany is a sudden fall-off in yield, which will be followed by full blown clinical symptoms.”

MacMahon confirmed that dairy farmers should review their grass tetany control strategies, where late calvers are concerned.

“Generally, cows are performing well in this area with 21L the average daily output being achieved. But the really good news relates to the quality of milk now available,” he said,

“Proteins of up to 3.45% are now commonplace with butterfats of 4.10% also achievable. This level of performance is helping to boost actual farmgate milk prices above the 27c/L base reported by a number of the processers for June milk.”

MacMahon said that getting second cut silage harvested is a priority for dairy farmers in the East Cork area.

“And they will need a dry weather window of at least 36 hours to make this happen. We are advising farmers that grass sugar levels have fallen over recent days with nitrate levels also rising. Both of these trends are a consequence of the recent wet weather.

“Last week daily grass growth rates on Glanbia monitor farms averaged 74kg DM/ha/day with demand at 59kg/ha. Surplus grass is building up on farms at present. As a consequence, grass quality is deteriorating.  Many dairy farmers will be pushing to take surplus paddocks out as baled silage, as soon as the weather improves.”

Looking towards the autumn, MacMahon said that dairy farmers will have an excellent opportunity to extend cow lactations and produce significant volumes of additional milk.

“But to make this happen, producers should consider feeding 3kg of concentrate per day from the beginning of September onwards. This will be dependent on grass supply.”

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