Effects of liquid protein feed on growth performance and ruminal metabolism of growing lambs fed low-quality forage and compared to conventional protein sources

Abstract

The present study was conducted to assess the inclusion of liquid protein feed (maize steep liquor; MSL) in growing lambs fed low-quality forage (400 g/kg wheat straw, dry mater basis) compared with two protein sources (soybean meal; SBM, and cottonseed meal; CSM). Eighteen male Farahani lambs, average body weight 36 ± 3.3 kg, were allocated to individual pens for 9 weeks. Three protein sources were: (1) MSL; (2) SBM and (3) CSM. Feed intakes did not differ among treatments. Growth rate and feed conversion ratio were improved in SBM-fed lambs. Nitrogen efficiency was improved in MSL v. CSM-fed lambs. Digestibility of fibre was enhanced in lambs fed SBM diet. Ruminal short chain fatty acid was highest in lambs fed SMB and lowest in lambs fed CSM. The urinary allantoin concentration was greater in SBM-fed lambs, with improved microbial crude protein synthesis. Blood urea nitrogen tended to be reduced in SBM-fed lambs. Dressing percentage improved in SBM-fed lambs. Lambs fed with SBM also grew faster and more efficiently than lambs fed either of the other two diets. However, regardless of the positive effects of SBM on the performance and ruminal fermentation profile observed in the current study, the MSL diet could be a profitable protein source in comparison to CSM in growing lambs fed low-quality forage. In conclusion, the present study indicates a positive outlook for feeding a liquid protein source to growing lambs fed low-quality forage such as wheat straw.

Protein Supplementation Improves Performance of Lambs Fed Low-Quality Forage

“…[22] The lambs' performance was improved by the addition of SMB to their diets. These results agree with those reached by other researchers [20,23] who reported that the ADG and the BW gain of different sheep breeds that consumed higher levels of protein supplements were enhanced by protein supplementation. In this study, the increase in the lambs' performance might be related to a moderately greater nutrient availability combined with higher supplement levels of SBM in their diets.…”

“…In the current study, the increase of hay intake may have increased the passage rate as well as the time needed by rumen microbes to access substrates indicating the positive response on digestibility due to protein supplementation. However, other studies have reported that supplementation of protein has no effect on nutrient digestibility [17,19,20]. They attributed that to the low-quality forage source and small particle size of the ration ingredients.…”

Effects of linseed oil and rumen undegradable protein:rumen degradable protein ratio on performance of Holstein dairy calves

“…All the above-mentioned performance traits responded to time throughout the study. This indicates that intake level, ADG and FE are influenced by animal age, which is mostly related to whole-body metabolism of the animal at different ages (38) . Zhao et al (39) clarified that younger animals have better nutrients efficiency in comparison with older animals, which could influence whole-body metabolism towards better efficiency.…”