A study has revealed that pumpkin seed cake, a by-product of pumpkin seed oil processing, can successfully replace soybean meal in the diet of dairy cows without negatively effecting milk performance and rumen fermentation.
Furthermore, an improvement in antioxidant functions of dairy cows was discovered.
Soybean meal is an excellent protein source used for ruminants because of its high protein content and excellent amino acid profile, however, high and variable soybean meal prices have led to attempts to partially or totally replace soybean meal.
Pumpkin seed cake (PSC), a by-product of pumpkin seed oil processing, could offer dairy farmers a valuable alternative feed as a beneficial protein source.
Researchers in China, therefore, conducted a study to evaluate PSC as a substitute for soybean meal in the diets of lactating cows based on performance, rumen fermentation, antioxidant function and nitrogen partitioning.
According to the researchers, PSC has a higher crude protein (CP, 598 g/kg) concentration than many commonly used oilseed-based feed ingredients, has high lysine (32 g/kg) and methionine (18 g/kg) content, and improves the palatability of concentrates to ruminants.
6 multiparous Holstein lactating dairy cows (body weight = 610 ± 21.5kg, days in milk: 95 ± 10.1, parity: 2, and milk yield = 28.7 ± 1.9) were randomly divided into 3 treatment groups:
The diets were isonitrogenous and contained identical roughage.
The replacement of soybean meal with PSC and DDGS did not influence:
Plus nitrogen partitioning between milk, faeces, and urine did not differ in the animals fed 1 of the 3 diets.
However, compared with a diet containing no PSC, the total antioxidant capacity and antioxidant enzyme (total superoxide dismutase, glutathione peroxidase, and catalase) activities were increased in the animals that received the 50PSC and 100PSC diets. In contrast, the addition of PSC significantly reduced concentrations of aspartate transaminase, alkaline phosphatase and malondialdehyde in the plasma.
These results demonstrate that PSC can substitute soybean meal in the diet of dairy cows without negatively impacting milk performance, rumen fermentation or apparent digestibility and that this dietary change improves antioxidant functions and blood parameters in dairy cows. The researchers, therefore, conclude that the study indicates that pumpkin seed cake has the potential for use as a feed source for dairy cows.
*The research team in China consisted of Y. Li, G. N. Zhang, X. P. Fang, C. Zhao, Y. X. Lan, L. Che, Y. K. Sun, J. Y. Lv, Y. G. Zhang from the College of Animal Sciences and Technology, Northeast Agriculture University, as well as H. Y. Wu from Jinlin City Academy of Agricultural Sciences, and C. F. Pan from Heilongjiang Technical Appraisal Station of Agricultural Products, Veterinary Pharmaceuticals and Feed in Harbin.
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