ABSTRACT: The high moisture content of wet distillers’ grains with solubles (WDGS) has limited its feeding value despite the relatively high nutritive value. The co–ensiling with whole–plant maize, as a complementary feed, was evaluated for growing lambs by formulating diets whose contents were: whole plant maize silage (WPMS) + sunflower oilcake meal (SOM) (control, WPMS + SOM), whole plant maize silage + dried distillers’ grains (WPMS + DDGS), and whole–plant maize (WPM) co–ensiled with WDGS (WPM – WDGS). Rumen fermentation parameters and in situ degradability of the diets were evaluated using three cannulated Merino wethers in a cross over 3 × 3 Latin square design experiment that lasted 39 days. Concurrently, feed intake and growth performance of South Africa Mutton Merino lambs (29.7 ± 3.6 kg) were evaluated over 45 days. The WPMS + DDGS diet had a lower rate of dry matter degradation (p < 0.05) compared to the WPMS + SOM and WPM–WDGS diets. However, the rapidly fermentable fraction, as well as the progressively fermentable fraction of the diet dry matter, was not different (p > 0.05). No differences in rumen volatile fatty acid, ammonia nitrogen concentration nor rumen pH of the wethers as a result of diet differences were observed. Lambs consuming the WDGS–based diet had a lower average daily intake and average daily gain (p < 0.05) compared to lambs consuming the DDGS and WPMS–based diets. However, the feed conversion ratio was not affected by diet differences (p > 0.05). In conclusion, co–ensiling WDGS with whole–plant maize provides the opportunity for the long–term storage and utilization of WDGS in lamb feeding.

ABSTRACT This study evaluated the potential utilisation of African yam bean (AYB) seed as a supplement to Guinea grass on in vitro gas and methane (CH4) production, as well as the effect of processing on AYB nutritive value. In experiment 1, unprocessed AYB meal at 10, 15, 20, and 25% inclusion levels was added to Guinea grass substrate and evaluated for in vitro gas production, CH4, and in vitro organic matter digestibility (IVOMD). In experiment 2, the effect of soaked, boiled, toasted, and fermented AYB meal at 20% inclusion on in vitro fermentation was evaluated. In vitro gas production as well as in vitro organic matter digestibility of Guinea grass increased with AYB supplementation. The associative effect of Guinea grass with AYB showed an increase in gas and CH4 production. At 20% inclusion level, AYB processing methods did not affect the gas production, CH4, and IVOMD of the substrate. Fermentation improved the crude protein, iron, and zinc contents, reduced acid detergent fibre concentration but did not reduce the concentrations of alkaloid, total phenol, saponin, and trypsin inhibitors of AYB. Seed soaking for 48 h reduced the total phenol, tannin, oxalate, and phytate content, while seed boiling reduced the concentrations of alkaloid, total phenol, tannin, and trypsin inhibitors. Compared with the raw AYB, boiling is the most effective processing method to reduce the investigated phytochemicals, followed by soaking, toasting, and fermentation, in that order.