Quick questions on Animal growth and development explained: HSC Agriculture Animal Production

Growth follows a sigmoid (S-shaped) curve. Early growth is slow, then accelerates rapidly through the juvenile and adolescent phase, then slows and plateaus as the animal approaches mature size. The fast middle phase is when feed converts most efficiently into liveweight gain, so producers aim to grow young stock quickly through this window to reach market weight sooner, which lowers cost and emissions per kilogram of product.

Tissues mature in a set order: nervous tissue and bone develop first, then muscle, and fat is laid down last and most heavily as the animal approaches maturity. This is why a young, growing animal is lean and a finished animal carries more fat. It also means that the same liveweight can represent very different carcases depending on maturity and breed: an early-maturing breed fattens at a lighter weight than a late-maturing breed. Producers use this to match breed and finishing weight to the fat specification the market wants.

Finishing is the process of bringing an animal to the target weight and fat cover for a specific market. A producer chooses the market (domestic trade lamb, heavy export lamb, feeder steer, grain-fed export beef), works back to the required weight and fat score, and feeds accordingly. Finishing may be on quality pasture, on a forage crop such as lucerne or brassica, or in a feedlot for grain-fed specifications. Drafting stock by weight and condition lets the producer turn off even lines that meet the buyer's requirements and attract premiums rather than discounts.