Providing cows are well conditioned and not over fat, it should be fairly straightforward for a large number of suckler herds and some of the less extreme dairy herds to economically sell cull cows back into the food chain.

But early pregnancy diagnosis is necessary, as the best time to start preparing the cow for finishing is during late lactation when nature switches the metabolism to weight gain.

Cull cows do not need to be fat.

A body condition score of four will be more cover than the market wants.

For an average sized cow one body condition score represents about 65kg liveweight. When they gain an average 0.75kg a day in late lactation, it would take less than 90 days to go from an average score of 2.5 to a more saleable 3.5.

Their killing out percentage is likely to be about 50%, so they gain about 50p a day.

Summer or autumn calvers fit perfectly for finishing at grass, which is the cheapest way of doing it.

Where there is an abundance of grass in spring and early summer run a few extra cows with lactating animals.

With winter and spring calvers, feed costs will be higher, but it will prove cheaper to finish them quickly in winter than trying to hold them until spring when grazing becomes available.

To get a decent return from dry cows on winter rations, they have to be gaining more than 1.5kg a day.

To do this they need to be on well balanced rations equivalent to 60% good forage and 40% high energy concentrates.

Then the feed conversion ratio should be 10:1-12:1, which equates to 12kg dry matter intake for 1kg liveweight worth 65p.

To leave a margin over feed alone, feed would have to cost less than 54/t dry matter, so on most farms cost for 1kg gain would be higher than the value of the gain.

When dairy cows are fed mixed rations, leaving prospective culls on the high yielders’ ration will probably suffice.

In feed to yield situations, ways should be found to feed high-energy, low-protein concentrates to culls.

The target should be to sell them finished as soon as they are fully dried off.

Specialist finishers will have access to suitable accommodation and cheaper feeds, either farm grown or local byproducts.

They will be looking for thin cows that can be bought cheaply and exhibit considerable compensatory gain during the feeding process.

Any cull cow going into winter scoring less than BCS 2.5 would best be sold for about 50p/kg liveweight, as it will cost the dairy or suckler farmer more to put on the extra weight than can be recouped from the abattoir.

The best of the compensatory gain will be achieved in the first month.

These gains are profitable, but after that response drops off, so the longer the animal is on intensive feed the more it eats into the profit made in the first month.

After 80 days on feed most animals will have used up all the financial benefit of compensatory gain, so it is worth sourcing animals from assured farms that can be turned over faster.

Rations should be high in energy and low in protein and 11-12% in dry matter.

They should contain some effective long fibre in the form of straw to spread carbohydrate load to avoid acidosis.

Some figures from the Republic of Ireland for average carcass grades of cull cows sold in 2003 show more than 42% of cows were P grade.

For these extreme dairy animals it is likely that the 87.4p/kg deadweight they will receive through the OTMS until the turn of the year will be the best return achievable.

With such animals a lower than 45% kill out can be expected, this would be equal to about 40p/kg liveweight.

The best demand will be for tall, well muscled cows that are naturally heavy.

Adding extra weight in fat will not be acceptable either from cost of production or wastage in manufacture.

Big 800kg plus suckler cows, particularly Continentals, should kill out at least 55%, make R grade or better and, provided they are not too fat, come to at least 600.

fwlivestock@rbi.co.uk