Milk fat secretion in lactating dairy cattle is influenced by soybean fatty acid profile and particle size Kristina weld November 3, 2015 Dairy showcase

Milk Fat Depression  Biohydrogenation Theory  Rumen microbes form bioactive FA from unsaturated feed FA  Absorption of bioactive FA in the small intestine  Bioactive FA act on genes in the mammary gland to downregulate milk fat synthesis and uptake of FA from the blood

Biohydrogenation Pathways

Linoleic Acid Pathway

Oleic Acid Pathway

Oleic vs. Linoleic Oils high in linoleic acid have been shown to be more fat depressing than oils high in oleic acid (He et al., 2012)  Produce more bioactive FA (trans-10, cis-12 CLA)

Linoleic vs. Oleic LOLL MOLL LOML HOLL LOHL MOML No FAT He et al., 2012

Particle Size Oil availability also influences biohydrogenation (Chilliard et al., 2009)  Free oil is more fat depressing than whole oilseeds  Too much at once for microbes to biohydrogenate successfully?

Particle Size

Much of the vegetable fat in dairy diets is linoleic acid. If that linoleic acid is replaced with oleic acid, then milk fat will increase. Summary

Soybean Fatty Acid Profiles Fatty AcidPlenishConventional 16: : : : :

Trial 1 Design 63 cows (28 primiparous, 35 multiparous) 111 ± 20 DIM Housed in one pen containing 32 Insentec RIC gates Covariate period followed by 3 a week treatment period Treatment diets containing whole raw Plenish beans (WP) or whole raw conventional beans (WC)

Diets Diet ComponentWCWP Alfalfa Haylage Corn Silage Concentrate16.8 High Moisture Corn Soybean Meal3.2- Whole Conventional Beans15.9- Whole Plenish Beans-19.1 Diets Diet Analysis WCWP aNDF CP Ether Extract Ash NFC

Production Treatments Multiparous (MP) Primiparous (PP) P-Value Variable WCWPWCWP SE dietparity Parity *diet MP diet PP diet DMI (kg/d) Milk (kg/d) Fat % Protein % Lactose % Fat (kg/d) Protein (kg/d) Lactose (kg/d) Milk (Mcal/d)

Conclusions Trial 1 There were no production effects in primiparous cows Plenish beans increased milk fat relative to conventional beans in multiparous cows

Trial 2 Design 20 cows (10 primiparous, 10 multiparous), 88 ± 10 DIM 5 diets fed in Latin squares 2x2 factorial of bean type (Plenish or conventional) and particle size (ground or whole, all raw) plus a low fat control

Diets Diet ComponentLFGCGPWCWP Alfalfa Haylage10.4 Corn Silage Concentrate A Concentrate B Concentrate C Ground Conventional beans Ground Plenish beans Whole Conventional beans Whole Plenish beans

Diets Diet AnalysisLFGCGPWCWP aNDF CP Ether Extract Ash NFC Starch

Production Diet Least Squares Means P-Values VariableLFGCGPWCWP SEFat Plenish *size WP vs. WC GP vs. GC Grou nd Plen- ish DMI (kg/d) Milk (kg/d) Fat % Protein % Lactose % Fat (kg/d) Protein (kg/d) Lactose (kg/d) Milk (Mcal/d)

Production Diet Least Squares Means P-Values VariableLFGCGPWCWP SEFat Intera ction WP vs. WC GP vs. GC Grou nd Plen- ish DMI (kg/d) Milk (kg/d) Fat % Protein % Lactose % Fat (kg/d) Protein (kg/d) Lactose (kg/d) Milk (Mcal/d) Conventional Average: 48.7 Plenish Average: 47.0

Trial 2 Conclusion There is a significant interaction between the particle size of soybeans and their fatty acid profile on milk fat concentration and yield.  Multiparous and primiparous

Overall Plenish studies confirm that substituting oleic for linoleic acid in typical dairy feeds can have a positive effect on milk fat. FA profile of soybeans may be more important when soybeans are ground rather than whole.

Implications If one is feeding/growing soybeans for dairy cattle then it would make sense to feed/grow Plenish rather than conventional beans As long as… yield/acre (cost) is similar between Plenish and conventional The decrease in milk production was not due to the difference in soybean FA profile. High oleic corn?

Acknowledgements Thank you to DuPont Pioneer for the donation of the soybeans! Thank you to all the barn staff – especially Sandy Trower and David Rieman – for making these trials run smoothly!

Questions?

Production Treatments MP PP P-Value Variable WCWPWCWP SE dietparity Interac tion MP diet PP diet DMI (kg/d) Milk (kg/d) Fat % Protein % Lactose % Fat (kg/d) Protein (kg/d) Lactose (kg/d) Milk (Mcal/d)

Production Diet Least Squares Means P-Values VariableLFGCGPWCWP SEFat Intera ction WP vs. WC GP vs. GC Grou nd Plenis h DMI (kg/d) Milk (kg/d) Fat % Protein % Lactose % Fat (kg/d) Protein (kg/d) Lactose (kg/d) Milk (Mcal/d)