2.2. Growth study animals, and treatments
Based on the mean of two consecutive daily live-weights at
the start of the experiment and on breed, seventy continental
crossbred finishing steers were grouped into blocks, and from
within blocks were allocated at random to one of 5 dietary
treatments (n=14):
1. Grass silage plus 3 kg concentrates/head/day (GS)
2. Maize silage plus 3 kg concentrates/head/day (MS)
3. Fermented whole-crop wheat plus 3 kg concentrates/head/
day (FWCW)
4. Urea-treated, processed whole-crop wheat plus 3 kg concentrates/
head/day (UPWCW)
5. Ad libitum concentrates plus 5 kg grass silage/head/day
(ALC).
Animals were housed in groups of 4 or 5 in slatted floor
pens (i.e. one treatment/pen). Replicate pens within a treatment
were positioned in different parts of the building. Forages in
treatments 1–4 and concentrates in treatment 5 were offered
ad libitum (at 1.15 times each animals daily intake) through
individual electronically controlled Calan gates (American
Calan Inc., Northwood, NH, USA) for 160 days. The same
concentrate, fed at 3 kg/head/day, was used to supplement the
four forage-based treatments in order to maximise the proportion
of the forage in the total diet and to be able to compare
the forages without the supplementary concentrates having a
confounding effect. It was formulated to a target crude protein
(CP) content of 190 g/kg DM in order to meet the animal's
requirements on the lowest protein forage, maize silage. The
supplementary concentrate contained 650 g rolled barley,
280 g soya bean meal, 50 g molasses and 20 g minerals and
vitamins/kg (839 g DM/kg) and was fed each morning before
animals were offered their daily allocation of forage. The
concentrate used in the ALC treatment contained 830 g rolled
barley, 100 g soya bean meal, 50 g molasses and 20 g minerals
and vitamins/kg (838 g DM/kg). All animals had continuous
access to clean, fresh water. Feed refusals were weighed daily
and discarded twice per week.