FEED EFFICIENCY ▶▶▶
Phytogenics improve the energy efficiency of ruminants
The efficiency of energy utilisation in ruminants co- determines the profitability of meat production, as well as its environmental
impact.Through genetic selection and the development of new technologies and methodologies the efficiency of ruminants converting feed energy into meat for human consumption can be improved.
BY GONÇALO MARTINS, DELACON BIOTECHNIK GMBH T
Feces consistency score(1) Fibers presence score(2) Sieve residue (%)
Starch in feces (g/kg DM) (1) 1 liquid à 5 hard (2) 1 short à 5 long 24 ▶ ALL ABOUT FEED | Volume 29, No. 8, 2021
he efficiency of energy utilisation in ruminants is a major determinant of the profitability of meat production, as well as its environmental impact. This is why it has long been a concern for animal
nutritionists and farmers. Through genetic selection and the development and application of new technologies and meth- odologies, animal scientists and producers have improved the efficiency of ruminants converting feed energy into meat for human consumption.
Energy efficiency Ruminants depend on microorganisms, through rumen fermentation, for digestion. During rumen fermentation, bacteria produce byproducts that can affect the efficiency of digestion. Furthermore, ruminants have a high maintenance requirement compared to other livestock (more than 50%
Table 1 – Effect of Actifor Power on fiber and starch digestibility (Delacon in vivo trial, Germany 2015).
Control 3.3 3.8
37.5 1.99
Actifor Power 2.8 3.6
29.0 1.82
of their feed intake). When comparing meat production through raising cattle to that involving other livestock, simple energetic efficiency is typically lower due to their reliance on forage and fibrous co-products as feeds and the role of fermentation in their digestion. Furthermore, fat and meat deposition are more energy expensive than milk production, leading to some differences even among ruminant animals.
Metabolic disorder: acidosis Feeding high-concentration diets favours growth in beef cattle, but an excessive amount of rapidly fermented starch could result in subacute ruminal acidosis (SARA). This intensive feeding system requires good control of ruminal fermentation since beef cattle diets are very low on fibre, impacting chew- ing and ruminating activities and saliva production and thus reducing the physiological buffering capacity of the animal. One of the most significant impacts of acidosis in beef cattle is the decrease of dry matter intake, which directly impacts the performance of the animals. This feed depression is linked with ruminal hypomotility by the direct action of the volatile fatty acids (VFAs) since chemical receptors in the epithelium send a feedback signal to the brain to reduce ruminal motility. In addition, severe liver abscesses, which result from acidosis, may reduce daily gain by 11% and feed efficiency by 9%. Also frequently associated with acidosis is diarrhoea, usually along with undigested feed material. Impaired ruminal function in terms of rumination, bacterial breakdown, and passage leads to changes in faecal aspects. When formulating diets for beef cattle, we should consider the total amount of starch and the ruminal degradability of cereal grains. We can consider two types of starch sources according to the starch degradation rate: - Fast degradable starch in grains and roots: cassava, wheat, barley and triticale.
- Slow degradable starch in grains and roots: rice, maize, sorghum and potatoes.
Intestinal digestion of starch As mentioned previously, starch from cereal grains is the pri- mary dietary energy source for highly productive cattle. For
PHOTO: RUUD PLOEG
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