What is winter calving and why do farmers calve their herds in autumn and winter months?
On the dairy side for the purpose of this article, we are suggesting it’s cows calving from September to December inclusive to supply fresh milk over the winter.
It means that the bulk of the milk produced from these autumn-calving cows will mainly be from cows milking indoors on silage.
Winter calving for some suckler farmers is an attempt to even out work across the year
Dairy farmers get a premium for milk produced in these months because it takes a lot more money to produce the milk during the winter months.
On the beef side, it’s cows calving in autumn, so that they calve outside and then calves are strong before they are housed for winter, meaning they are well grown when they hit grass in the spring. Winter calving for some suckler farmers is an attempt to even out work across the year.
How many cows calve in winter?
In the Republic of Ireland, just shy of 10% of total calvings take place in the four months from September to December inclusive – this is 9% to be specific or 216,880 calf registrations of the 2,387,821 registrations in 2020 (Figure 1).
Of those 216,880 calvings, there are 92,932 Friesian cows that have a calf and 123,948 beef cows that have a calf in that four-month window (Figure 2).
If we isolate the beef cows, the majority of them are Limousin-bred cows, followed by Charolais, Angus and then Simmental (Figure 3).
Of the calves registered in this four-month window, what is the breakdown of the breeds?
Figure 4 shows the breakdown of the 216,880 calves registered in 2020 by breed. So there were 57,247 Friesian calves born, 52,409 Limousin calves and so on.
So by far the majority of calves that are born in this period are beef-sired calves.
Of the 57,247 Friesian-bred calves, approximately half will be female dairy replacements, so in effect there are only approximately 28,000 Friesian bull calves born in the Republic over the four-month period from September to December inclusive.
In Northern Ireland in total, 528,950 cows (dairy and sucklers) calved in 2020. The approximate percentage breakdown per month of dairy calvings can be seen in Figure 5.
As expected, the profile is pretty flat with a dip in the summer months, but peaking in October.
So if approximately 45% of the milking cows in Northern Ireland calve in the four-month window from September to December inclusive, that’s about 150,000 dairy cows calving during this period.
So that 150,000 cows is about half of the total dairy cows in Northern Ireland, while the 92,000 dairy cows calving south of the border during this four-month window is only about 9% of the total cows that calve in the Republic.
Of calf registration in the beef breeds, Aberdeen Angus and Limousin were the biggest with 25% of calves sired by each, respectively, followed by 22% sired by a Charolais sire.
Hereford comes next at 7%. These calf registration numbers don’t include Holstein Friesian-sired calves.