Growth, or ‘gain in weight’, has a crucial effect on the commercial value of livestock. The value of an animal which is to be sent for slaughter depends mainly on:

> the amount of muscle on the carcass, i.e. its ‘conformation’

> the quantity and quality of its adipose tissue (a criterion which affects the price per kilo of the beef), i.e. its ‘fattiness’, called ‘marbling’ by the butcher.

Other factors, such as the conditions in which the livestock was raised, or its breed, can also affect value, independently of the effect they may have on conformation and finish (degree of fattening), because of the image they conjure up. For instance, some consumers are ready to pay more for beef reared extensively, or on farms which meet the criteria of organic farming, or from a particular breed.

At puberty (15 months, from 350 to 400 kg live weight), the animal grows at its fastest rate, which then drops off as it gets older.

In cattle production, an animal’s growth curve is not constant but depends on available feed (or forage), as well as on the animal’s future role in production (replacement female, store animal, steer, etc.) The calf must be in good health both before and after weaning if it is to develop well. In all cases, before it is one year old, the bovine’s feeding should not be subject to too many restrictions, so that it may develop well and subsequently express its maximum capacity for beef production or breeding.

Weaning: in suckler production, the calf remains with its mother from the time it is born until the age of 6 or 8 months, so as to get the most benefit from its milk for growth. The calf is said to be ‘at foot of dam’. At this age, when the dam’s milk production is relatively low, the calf is separated (‘weaned’) from its mother, and from then on is given exclusively ‘solid’ feed, based on forage and concentrate, as well as water to drink. This allows the dam to rest and complete gestation of her next calf. The aim of the producer is to obtain one calf per cow per year.

We can distinguish between three different types of growth:

> constant, steady, rapid growth for livestock raised intensively, such as beef calves (slaughtered between 5 and 6 months old, from 200 to 260 kg live weight, or early maturing young bulls (slaughtered before 20 months, over 500 kg live weight) (line 1),

> irregular growth, with one phase of slower growth lasting 2 years, for young steers and ‘early maturing’ heifers (line 2),

> irregular growth, with several phases of slower growth in winter, lasting more than 3 years, for extensively reared livestock, steers and heifers (line 3).