THIS is the time of year when thousands of weaned beef calves, or suckled calves as we call them, are sold at markets around Scotland.

Scotland has a relatively small national herd of about 440,000 beef cows that produce around 400,000 suckled calves, of which about 40,000 are kept as herd replacements and the rest fattened as prime beef.

Although beef cows, like dairy cows, can calve all year round, most are either calved in the spring or autumn, with spring calving being the most popular.

Autumn calving herds calve in September and October, and the resulting calves are fattened off grass in their second grazing season, or finished indoors to be slaughtered in the run-up to the lucrative Christmas trade.

Spring-born beef calves also spend their second summer at grass and are then fattened indoors during the winter to be slaughtered at about 22-months of age around January, February and March.

Autumn calving has fallen out of favour over the years for a number of reasons, the main one being it is a more expensive option.

Cows suckling their calves during the winter months have to have their rations of forage supplemented with expensive concentrated feed, while their growing calves also need expensive feed in addition to their diet of milk and fodder. That additional supplementary feeding often continues while the calves are suckling their mothers at grass, and after weaning in July or August until they are put indoors for the winter.

Another problem with autumn-calving cows is that, unless they winter out-of-doors, they have to be served by the bull when they are indoors, and that can lead to bulls being seriously injured as a result of slipping on concrete.

To overcome that, many stockmen move cows that are in heat to an area bedded with straw, or outside to a field where the bull can serve them without risk of injury.

Spring-calving cows don't suckle calves during the winter months and as a result can be fed cheaper, forage-based diets and only a small amount of expensive concentrated feed in the run-up to calving. Better still, their rapidly-growing young calves are big enough to take advantage of their mother's increased milk production as a result of grazing the lush grass that grows in the spring.

While spring calving is a cheaper system of beef production, it runs the risk of various diseases among the young calves while they are indoors. To overcome that, many now calve their cows in April or May, rather than February and March, and turn the cows with their young calves out-of-doors to a healthier environment at grass, once everything is seen to be OK.

Another problem with the increased popularity of spring-calving is that there is now a glut of 22-months-old prime cattle on the market around the end of February that depresses prices.

Some keep their weaned calves through the winter to fatten at a later stage, while many sell them as growing, store cattle the following spring to be fattened on better farms. Quite a few, with limited supplies of winter fodder, particularly those on poorer, hill and upland farms have calculated that it is more profitable for them to sell their suckled calves at this time of year, rather than face the expense of buying in extra fodder or feed.

Between 2010 and 2013 the number of store cattle and suckled calves being bought out of Scottish auction marts to travel south of the border for fattening rose to a peak of about 23,000 head per year, or about 12-13 percent. Those "official" figures didn't include private deals done between farmer and farmer.

The attraction of Scottish marts was that they tend to have big sales of quality beef cattle - often with six or seven hundred, and several regularly selling over 2000. That gives southern buyers the confidence of being able to fill a large cattle transporter at one sale.

The other attraction was that Scotland is free of bovine TB, unlike England and Wales where the disease is widespread and buying down there ran the risk of introducing the disease to a "clean" farm.

The loss of those cattle to southern buyers was a concern for Scottish abattoirs keen to maintain their throughput of valuable Scotch Beef to meet demand from export markets. Fortunately for them that trade has declined in recent years to between seven and eight per cent of Scotland's throughput of store cattle.