Three studies evaluating palatability, nutrient utilization/N balance, and performance responses to long-term feeding of expeller-pressed (EKC) and solventextracted (SKC) Pongamia seedcake (PSC) were conducted. In Experiment 1, increasing amounts of either EKC or SKC mixed with wheat middlings (WM) were offered to steers to evaluate the palatability of PSC. Rate and extent of consumption were measured. Observations indicate that SKC is more palatable than EKC, and could be included at up to 40% of supplement without impacting consumption; 20% EKC may be effective for cattle consuming low-quality forage. In Experiment 2, isonitrogenous
(100 mg of N/kg BW) amounts of supplements containing EKC or SKC were infused into steers consuming low-quality forage to compare effects of provision and level of PSC on forage utilization. Forage intake was not affected by 20% EKC or 40% SKC. An increase in forage intake was observed with the supplement when no PSC was included, but supplementation with 40% EKC decreased forage intake. Total tract digestion was not affected. All steers were positive for N balance. Nitrogen retention for all PSC-containing supplements was less than the positive control, but more than the negative control. Karanjin and pongamol intake and absorption was greatest for 40% EKC and least for 40% SKC when comparing PSC supplements. Based on these results, 40% EKC does not seem to be a viable option, but 40% SKC and 20% EKC could potentially be utilized as protein supplements for beef cattle on forage-based diets. In Experiment 3, fifteen steers were fed either a positive control (0% PSC), 20% EKC, or 20% SKC supplement for 126 days to determine the long-term effects of feeding PSC. The control supplement resulted in greater OM intake compared to 20% EKC and 20% SKC. Average daily gain of steers on either PSC supplement was significantly lower than that of control steers, but similar to one another. Control steers were more efficient than PSC supplemented steers, and 20% EKC steers were more efficient than 20% SKC steers. Further research comparing performance of animals fed EKC and SKC should be conducted as PSC research in cattle is limited.
- Sawyer, Jason Associate Professor and Associate Department Head