Effect of supplementation with urea, blood meal, and rumen-protected methionine on growth performance of Holstein heifers grazing kikuyu pasture

Abstract

Supplements with corn grain, molasses cane, and different nitrogen sources were evaluated in 16 growing Hosltein heifers [227 ± 33 kg body weight (BW)] grazing kikuyu (Pennisetum clandestinum) pasture in a 10-ha sward (rotational grazing with electric fences) during 90 days in the summer season. The nitrogen sources were urea (U); urea and blood meal (U+BM); and urea, blood meal, and rumen-protected methionine (U+BM +RPM). Heifers were randomly assigned to four experimental supplements defined as follows: control (no supplementation), U, U+BM, and U+BM +RPM. Two kilograms (as fed) of supplement was offered daily. The final BW of heifers fed U+BM +RPM was higher (P<0.05) than heifers not supplemented. The total and average daily weight gain of heifers supplemented with U+BM +RPM were higher than heifers not supplemented or supplemented with U and U+BM (P<0.05). The average daily gain of heifers supplemented with U and U+BM were higher than heifers not supplemented (P<0.05). Grass intake was not affected by supplementation, but total dry matter intake was increased by supplements with U, U+BM, and U+BM +RPM (P<0.05). Feed conversion was improved by U+BM +RPM (P<0.05). Total tract digestion was not affected by supplements. Blood urea nitrogen concentrations of heifers supplemented with U, U+BM, and U+BM +RPM were higher than heifers not supplemented (P<0.05). It is concluded that supplements with U+BM +RPM improved growth performance and feed conversion in heifers grazing kikuyu pasture.

Effect of herbal choline and rumen-protected methionine on lamb performance and blood metabolites

“…Sanchez et al (2012) evaluated 5 g/d of RPM in growing lambs fed with rations based on corn stover and did not find any effects of the amino acid on growth, intake or feed efficiency. In contrast, Gomez et al (2011) demonstrated that grazing heifers exhibited improved growth in response to the dietary addition of RPM when a source of bypass Lys was included in the supplement. Madsen et al (2005) found a positive effect in dairy goats in milk production, but only when Met was combined with rumen-protected Lys at a Lys to Met ratio of 2.55 : 1.…”

“…Previous experiments using rumen-protected methionine (RPM) in growing lambs have not been successful, presumably because the diets were based on low-quality forage with inadequate lysine (Lys) and Met flows (Sanchez et al, 2012). In contrast, grazing heifers supplemented with RPM and complemented with sources of bypass Lys improved average daily gain (ADG) (Gomez et al, 2011). The NRC (2007) indicated that choline requirements have not been established for sheep, but suggested that production could be improved by using it as a supplement.…”

Effects of 2‐hydroxy‐4‐(methylthio) butanoic acid isopropyl ester on growth and blood components in growing Holstein steers

“…It has also been found that the total and average daily weight gain of heifers supplemented with U (urea) + BM (blood meal) + RPM (rumen‐protected methionine) were higher than the corresponding rates of heifers either not supplemented or supplemented with U or U + BM (Gomez et al . ).…”

Effect of ruminally protected methionine on body weight gain and growth of antlers in red deer (Cervus elaphus) in the humid tropics

“…Some grazing experiments with cattle have shown positive responses of the growth of steer to the dietary addition of RPM (Gomez et al 2011), whereas other studies have shown no effect (Liker et al 2006) at doses of 10 g/day. The reason that the intermediate dose decreased weight gain in this experiment is unclear, but the possibility that deer respond to higher doses than those used in this experiment should not be excluded.…”