The heifer above was slaughtered recently. At 20 months of age, a U+ carcass weighing 327kg was produced. Her sire is the impeccable Charolais bull LGL, and let it be known that I do not hold a bias toward any particular breed – he is simply doing the business here. The dam is by ROX, a terminal Limousin. The weight may sound decent, but it is slightly behind what we’d expect from such a gene pool. There is a valid reason however.

The question is her fat score – what was it?

Three main principles affect fat deposition in cattle. Firstly, as an animal progresses towards maturity it fattens. Mature weight is typically lower for an Angus than a Charolais, hence we see breed differences in terms of fatness at a given age or weight. A loose definition of mature weight is that point at which the animal’s body composition is 25% fat.

Secondly, gender-driven hormones cause heifers to be fatter than bullocks, which in turn are fatter than bulls. And thirdly, if the energy density of an animal’s diet is such that there is surplus once all other needs have been met, fat will be laid down. This is the principle that finishers use to produce fit cattle at a young age. Feeding young cattle intensively can almost re-program mature weight if enough fat deposition occurs.

Leg break

My heifer had an uncomfortable first few days. She was accidentally trodden on by her mother, breaking a front leg and damaging her hip. Her break healed, but the animal had a visible limp stemming from her hip. The vets were happy that she was pain-free and encouraged us to keep her on straw and finish her early.

She turned out in March and ran with cows and calves for four months, before hitting straw again. She received 4kg of 13% crude protein ration with silage for a further four months and was slaughtered last week. Usually, our beef heifers get no more than 80 days on such a ration, but this was an exception.

Though her carcass weight seems healthy, it was obvious that her thrive had slowed in the final six weeks. Her fat score was a 1-, i.e. she could not have been leaner. Baffled, I went to the chill to investigate and sure enough she was as red as a Honda Civic in an empty Tesco carpark.

There’s a Blue Peter badge waiting for any of you who guessed right. So what happened? What does science say?

Theory

My theory is that her intake plateaued early-on in the finishing period. She ate her concentrate allowance enthusiastically each day, but silage is a vital component in such a diet too. As far as silage goes, she ate enough to keep her stomach happy and sat for the rest of the time. Her impaired mobility affected her desire to eat. There wasn’t enough energy going in to encourage the laying down of fat.

This week, we kill a number of genetic carbon copies. I am confident they’ll creep into the 400kg’s. She was docked 60 cents per kilo and there are few viable destinations for such carcasses.

It’s a shame. So much potential; like a promising young footballer who discovered the bar stool and the fairer sex too early.