Whilst nutrition is a key element to get right, Kevin urged farmers to take a holistic view of farm management and also focus on environmental and health factors, in order to ensure that animals achieve their full potential.
“Barriers to optimum feed efficiency can often be lifted quite simply, by removing areas of stress such as abrupt pen moves or bullying at the feed barrier,” explained Kevin.
Increasing head space at feed barriers can result in increased intakes and lying times, with animals spending less time and energy standing and waiting for feed. Farmers operating total mixed ration feeding systems or forage plus concentrates (for liveweights of 400kg-650kg) should aim to provide 55-65cm of head space per animal, and those running ad lib, hopper-based feeding systems, 28cm of space. Providing a smooth trough surface, with good footing and consistently fresh feed (and with rejected feed regularly removed), were some of Kevin’s other recommendations for helping to achieve optimum intakes.
Kevin warned that, management-wise, there are many invisible areas on the farm where profits can disappear under the radar. It could be a silage clamp where unseen losses are occurring due to aeration, or a poorly ventilated building causing respiratory disease challenge to the herd. In terms of the former example, research in Ireland from Teagasc (P. O’Kiely, 2014) has estimated that 15-30% DM silage never reaches the animal due to losses in the field, the clamp, the face and in the trough. Similarly, ventilation-wise, research by Westpoint Vets found that dairy crossbred calves with severe lung damage caused by pneumonia displayed a 0.2kg/day reduction in liveweight gain from birth to slaughter.
Common diet targets - beef cattle
|
Growing cattle |
Finishing cattle |
|
|
Dry matter intake (DMI) |
2-2.5% bodyweight |
~2% bodyweight |
|
Target daily liveweight gain (DLWG) kg |
0.7-1.2 |
>1.3 |
|
Metabolisable energy (MJ ME / kg DM) |
10.5-11.5 |
>12.2 |
|
Crude protein (CP) % |
12-16 |
12-14 (16% young bulls) |
|
Starch & Sugar % |
<20 |
>20-25 |
AHDB (2016)
From a nutritional standpoint, looking after the rumen is critical for obtaining the best growth rates in beef animals. Here a consistent diet, appropriate to the breed, sex and age, is hugely important, as Kevin explained: “Every diet should have a roughage element which for finishing cattle should ideally be straw and preferably wheat, chopped between 2-4 inches/muzzle width to avoid sorting. Also, ensure cattle do not run out of feed when on ad lib rations or high levels of concentrate feeding, as this can lead to gorging and increase the risk of rumen upset.”
“Any ration changes should be made over a two to three-week period to allow the rumen microbes to adapt gradually. Always change diets slowly, building up every three days if there is no sign of digestive disturbance. For cattle coming from grass it can be beneficial to introduce the finishing ration whilst still grazing to ease the transition onto the new diet.
Rapid diet changes can cause digestive disorders such as acidosis as the rumen bugs don’t have time to adapt, resulting in long-term damage to rumen papillae, which are vital for nutrient absorption which will negatively effect feed efficiency.
“The diet needs to include balanced energy sources, such as digestible fibre in the form of beet pulp/soya hulls etc., as well as starches and sugars, e.g. forages, cereals & byproducts. It is important to test home-grown forages regularly and formulate diets accordingly. Protein-wise it is essential to tailor the protein level to the type of cattle you are feeding with young, fast growing animals having the highest requirements and mature cattle the lowest. As with all ruminants, always ensure that there is a clean, palatable supply of water available - finishing cattle can require as much as 80 litres of water a day.”
A key point that Kevin highlighted was that animals of different breeds and genetics will respond differently to the same management.
“Every animal brings with it a package of genetics, which determine its feed efficiency potential. Genetics and animal factors include breed but also whether the animal is a heifer, steer or bull and its age and stage of maturity. If you take a native breed, such as an Aberdeen Angus or Hereford, they are much more genetically predisposed to lay down fat. Diets for these animals should also contain less starch to prevent heifers in particular becoming over fat at an early age, this can be easily achieved through an increased utilisation of grass/forage in the diet. Remember fat gain is four times less efficient than lean gain and we should be targeting the minimum required to hit the desired specification. Similarly, bulls are more feed efficient than steers, which in turn are more efficient than heifers. The way we manage each animal determines how much of the genetic potential we realise,” said Kevin.
With feed efficiency decreasing with age, he reminded farmers that it is essential to maximise high feed efficiency early in life and be very clear on the length of time an animal remains economically feed efficient on the farm: “Maintenance is largely a function of weight, so a heavier animal requires more feed to maintain itself. Furthermore, for a fixed rate of liveweight gain, the feed energy required to achieve this gain is higher for heavier animals.
|
Comparison of feed efficiency |
|||
|
Bulls |
Steers |
Heifers |
|
|
Start weight (kg) |
130 |
148 |
135 |
|
Slaughter age (months) |
13.6 |
13.0 |
13.1 |
|
Daily liveweight gain (kg from birth) |
1.29 |
1.23 |
1.12 |
|
Carcase weight (kg) |
317 |
283 |
261 |
|
FCR (kg Feed DM: kg liveweight gain) |
5.43 |
5.69 |
5.81 |
S. Marsh (1997)
“Feed efficiency is therefore better in lighter, fast growing animals, which in turn help producers avoid overly long finishing periods and ensure that animals achieve optimum carcass fat score without impairing carcass value.” As well as being feed efficient, however, Kevin stressed that diets must also be cost effective and fit with the farm system (i.e. make use of ruminant’s propensity to consume by-products, forages etc.)
When animals are ready to move on and the time has come to sell cattle, Kevin urged farmers to be pragmatic in their decision making and get cattle off farm as soon as they have hit their target weights, irrespective of market conditions. "When looking to sell cattle, it never pays to keep animals beyond their optimum weight,” concluded Kevin. “Even if prices are low, let cattle tell you when they are ready to go, rather than the markets.”
Summary:
To improve feed efficiency:
-
Provide a balanced diet
-
Tailor diet to the type of animal
-
Be consistent from feed to feed
-
Minimise opportunities for animal stress
-
Maximise growth in early life
-
Finish animals earlier