| Abstrakt: |
Commercial concentrates are the main supplemental feeds used by farmers in Trinidad and Tobago (T&T) to off-set nutritional or herbage deficit of forage-based diets for ruminants. While the crude protein (CP) contents of these commercial feeds are known, the quality of the protein for different classes of ruminants is unknown. Therefore, this study examined the nitrogen and crude protein fractions and ruminal CP degradability of the most popular concentrate feeds used for feeding ruminants in T&T. Eight commercial concentrate feeds from two leading manufacturers were collected over a 5-month period. These feeds comprised three dairy rations (DR-1, DR-2 and DR-3), two small ruminant rations (SR-1 and SR-2), two all-purpose rations (APR-1 and APR-2), and a dry cow ration (DCR). The eight feeds were evaluated for total nitrogen (N), buffer soluble N (BSN), buffer insoluble N (BISN), non-protein N (NPN), neutral detergent insoluble N (NDIN), acid detergent insoluble N (ADIN), protein fractions A, B1, B 2, B3, C, true protein, rumen degradable protein (RDP), rumen undegradable protein (RUP) and in vitro ruminal crude protein degradability. CP contents were highest in DR-2 (206 g/kg DM) and lowest in SR-2 (139 g/kg DM). APR-2 had the highest BSN (336 g/kg DM) and NPN (189 g/kg DM) and the lowest ADIN (21.1 g/kg DM) and BISN (664 g/kg DM) contents. Crude protein fraction B1 was lowest and B2 was highest in DR-2. Feeds with the highest and lowest RUP contents were DR-2 (150 g/kg DM) and SR-1 (82.6 g/kg DM), respectively. Highest 3-hour in vitro ruminal CP degradability was observed in APR-2. It was concluded that protein quality of commercial ruminant feeds in T&T varies with feed type, with DR-2 and SR-2 having the highest RUP contents to support the lactating dairy cow and fattening lamb, respectively. [ABSTRACT FROM AUTHOR] |
