FRESH COW NUTRITION: EFFECTS OF WHOLE COTTONSEED & FAT SUPPLEMENTATION

Nutritional strategies that increase the energy content of the diet without compromising rumen function are critical during the immediate postpartum period. Supplemental fatty acids (FA) and oilseeds in diets have been used to increase postpartum energy intake. Specifically, whole cottonseed (WCS) is commonly included in dairy cow diets due to its high FA and crude protein content. However, more research is needed on how WCS and FA supplementation interact, and the effect of feeding WCS immediately postpartum.

A recent study by Parales-Girón et al. (Journal of Dairy Science, 2025) at Michigan State University sought to address these questions. The study evaluated the effects of supplementing whole cottonseed (WCS) and a palmitic- and oleic-acid–based fat source on dry matter intake (DMI), milk production, and metabolic responses of dairy cows immediately after calving. These findings can provide farmers with valuable insights into how these fat sources can be used to improve milk fat yield, energy-corrected dairy, and feed efficiency in fresh cows.

In the study, 52 multiparous cows were either fed a diet (1) containing no WCS or supplemental FA, (2) containing WCS at 10% diet DM, (3) supplemented with calcium salt containing 60% palmitic acid and 30% oleic acid at 1.9% diet DM, or (4) containing WCS and the palmitic + oleic acid calcium salt. Treatment diets were fed only during the first 21 days postpartum, which, although metabolically relevant, may have reduced the ability to detect effects of longer-term supplementation.

Cows fed a palmitic and oleic acid blend had improved milk production responses without compromising DMI or body energy reserves. Specifically, improvements in milk fat yield by 14.6% and energy-corrected milk (ECM) by 8.5% were observed. The same improvements were observed in cows fed WCS, with a 16.2% increase in milk fat yield and a 12.6% increase in ECM. Additionally, cows fed WCS showed increased protein yield by 8.2% and an increased lactose yield. Furthermore, the DMI intake of cows fed WCS increased by approximately 3.0 kg/d (14%) during the treatment period. This is likely due to the fiber provided by WCS, which helps maintain a healthy rumen environment and can prevent excessive acid buildup that reduces appetite.

Although WCS and FA supplementation improved milk production when fed individually, co-administration did not yield additional benefits; rather, the positive responses observed were attenuated. This suggests that their individual benefits may not be complementary. This is simply due to the different pathways WCS and FA follow during digestion. FA are inert in the rumen, meaning they do not break down and pass directly through the rumen. They are then broken down once they reach the abomasum, with further absorption occurring in the small intestines. On the other hand, WCS are slowly broken down in the rumen, allowing for a gradual release of oil. Additionally, the moderated intake from the combined treatment is likely due to increased duodenal flow of fatty acids, which stimulates gut peptides that can suppress appetite.

Body weight and body condition score loss were not affected by any treatment in this study. Additionally, blood markers indicated normal metabolic adaptation during early lactation, with no major health concerns.

Overall, the major takeaways from this study suggest that feeding either WCS or supplemental FA can improve milk production immediately postpartum. WCS can improve milk fat and protein yield, and supplemental FA can improve milk fat yield, but feeding them together offers no added benefit.

̶ Corina Warren

cwarren@whminer.com