Methionine-balanced diets improve cattle performance in fattening young bulls fed high-forage diets through changes in nitrogen metabolism

Abstract

Ruminants fed high-forage diets usually have a low feed efficiency, and their performances might be limited by methionine (Met) supply. However, the INRA feeding system for growing cattle does not give recommendation for this amino acid (AA). This study aimed to assess the effects of Met-balanced diets on animal performance and N metabolism in young bulls fed high-forage diets formulated at or above protein requirements. Four diets resulting from a factorial arrangement of two protein levels (Normal (13·5 % crude protein) v. High (16·2 % crude protein)) crossed with two Met concentrations (unbalanced (2·0 % of metabolisable protein) v. balanced (2·6 % of metabolisable protein)) were tested on thirty-four fattening Charolais bulls for 7 months before slaughter. Animal growth rate was greater in Met-balanced diets (+8 %; P = 0·02) with a trend for a greater impact in High v. Normal protein diets (P = 0·10). This trend was observed in lower plasma concentrations of branched-chain AA only when Met supplementation was applied to the Normal protein diet (P ≤ 0·06) suggesting another co-limiting AA at Normal protein level. Feed conversion efficiency and N use efficiency were unaffected by Met supplementation (P > 0·05). However, some plasma indicators suggested a better use of AA when High protein diets were balanced v. unbalanced in Met. The proportion of total adipose tissue in carcass increased (+5 percent units; P = 0·03), whereas that of muscle decreased on average 0·8 percent units (P = 0·05) in Met-balanced diets. Our results justify the integration of AA into dietary recommendations for growing cattle.

Common and diet-specific metabolic pathways underlying residual feed intake in fattening Charolais yearling bulls

“…As previously reported 14 , the RFI differences between Low and High-RFI animals averaged 1.48 kg DMI. Accordingly, the daily intake of organic matter, crude and metabolizable protein, neutral detergent fiber and net energy were also lower (− 13 % on average, P < 0.01) for Low- versus High-RFI animals, irrespective of diet (Table 1 ).…”

“…The average daily gain (ADG) of each animal was calculated as the slope of body weight regressed on time. Ultrasound echography (Easi-Scan, BCF Technology Ltd., Vienne, France; equipped with a linear probe) was conducted in three different anatomical regions at end of the RFI test as previously described 14 . Distances analyzed from each anatomical place were the skin (D0) and back fat thickness (D1) that include both subcutaneous tissues and skin.…”

Analysis of Chemical Composition, Amino Acid Content, and Rumen Degradation Characteristics of Six Organic Feeds

“…Amino acid content is an important indicator for judging the protein nutrition of roughage. Protein content and composition can directly affect the growth of the cattle [27] and can also indirectly affect nitrogen metabolism [28]. Our study showed that the EAA content of SC is the highest, or it can be used as a source of high-quality EAA to adjust the balance of amino acids in the diet.…”

Identifying cattle with superior growth feed efficiency through their natural 15 N abundance and plasma urea concentration: a meta-analysis.

“…This is because on one hand, DM intake and N intake correlate positively at the individual level even if feed sorting occurs (Dykier et al, 2020). On the other hand, BW gain and N retention are highly correlated since protein and the associated water retention may account for 55-75% of the BW gain in growing-fattening cattle (estimations from values reported in Geay, 1984 andCantalapiedra-Hijar et al, 2020a). The theoretical association between feed efficiency and NUE has been empirically confirmed in dairy cows with contrasted RFI values (Liu and Van de Haar, 2020) and in beef cattle ranked according to FCE (Nasrollahi et al, 2020).…”