Molasses as an Alternative Energy Feed Source for Organic Dairies

Organic dairies are faced with the challenge of sourcing and purchasing organic feed grains. These grains particularly corn, are often in short supply and highly expensive. This study replaced the traditional corn meal (CM) found in many organic dairy rations with liquid molasses (MOL). Molasses was chosen for its high palatability and high energy content. To complete this study 20 lactating Jersey cows from the Burley-Demeritt Organic Dairy Research Farm of the University of New Hampshire (UNH) were utilized to investigate the effects of liquid MOL vs. CM on milk production, milk composition, and nitrogen (N) utilization. Income over feed cost (IOFC) analysis was also done to determine whether profitability is improved by feeding MOL over CM. The feeding trial began in June 2010 and ended in September 2010 with most of the laboratory analyses completed in 2011. Cows in this study had access to mixed species pasture for about 18 h/day from June to mid-September. Along with pasture a ration consisting of approximately 2.0 kg of dry matter (DM) from either MOL or CM along with 3.0 kg of DM from a grass-legume mix baleage was fed to cows twice daily. Cows fed MOL had increased (P < 0.01) supplement (MOL + baleage) DM intake (DMI). Pasture DMI was numerically higher in cows supplemented with MOL resulting in numerically higher total DMI (supplement + pasture). Milk yield was also numerically higher (+1.0 kg/d) in cows fed MOL vs. CM. Concentrations of milk urea N (MUN) and plasma urea N (PUN) were both significantly decreased in cows fed MOL vs. CM indicating improvement in N utilization. However, despite the slight numerical increase in milk yield in cows fed MOL, the cost of feeding it was $0.24/lb higher compared to MOL resulting in reduced IOFC.

Introduction:

As milk prices fluctuate and input costs increase, dairy farms seek lower-cost feed alternatives to maintain or improve milk production while reducing feed costs to improve overall farm profitability. This has been most evident within the organic dairy sector, as organic grain prices have been traditionally higher relative to conventional grain prices. Thus, organic dairy farmers have experimented with a variety of supplemental grains and alternative feed sources, including molasses.
Sugar cane MOL is a rich source of sugars, particularly sucrose, is available in organic form, and may be a viable supplement option in place of CM. However, there is little literature available that evaluates MOL as the only supplement for grazing dairy cows. Anecdotal results, as reported by organic dairy farmers, are mixed - some farms use MOL successfully while others report major milk production or body condition losses. Also, it has been anecdotally proposed that MOL has three times more energy than CM, allowing for a lower feeding rate. While there is research available that evaluated MOL as an energy supplement in confined dairy cows. There is no specific data available in the scientific journals regarding the impact of using MOL as the only supplemental source of feed to grazing dairy cows. Additionally, there is no research data available to verify that molasses is higher in energy, as it is generally considered to be equivalent to CM.
Feeding a high energy source like MOL or CM is critical for balancing the dietary needs of grazing dairy cattle. Pasture tends to be very rich in rumen-degradable protein which is transformed into ammonia in the rumen. A high energy feed source is necessary to balance the rumen-degradable protein which allows for the conversion of ammonia into microbial protein. If a high energy feed source is not available, ammonia will be detoxified to urea in the liver and lost as N in urine, which is major source of environmental pollution. Not only does the lack of a high energy feed source result in increased N excretion to the environment, it can also lead to some serious negative impacts on the dairy cow (NRC, 2001). The process of detoxifying ammonia to urea through the urea cycle in the liver is an energy expensive process that requires the cow to draw energy from her body stores (NRC, 2001). Cows with high levels of circulating urea tend to lose body condition and suffer from poor reproductive performance. Sucrose present in MOL is more quickly degraded in the rumen than starch present in CM (Chamberlain et al., 1993), thus suggesting that feeding MOL can balance the supplies of energy and degradable protein in the rumen leading to improved N utilization in grazing dairy cattle.
We hypothesized that MOL supplementation will enhance N utilization and microbial protein synthesis which may be responsible for the positive responses in milk production, milk composition, and body condition anecdotally observed by organic dairy farmers currently feeding MOL.

REFERENCES:
National Research Council. 2001. NRC. Nutrient requirements of dairy cattle. 7th rev. ed. Natl. Acad. Sci. Washington, D.C.

Chamberlain, D. G., S. Robertson, and J.J . Choung. 1993. Sugars versus starch as supplements to grass silage: Effects of ruminal fermentation and the supply of microbial protein to the small intestine, estimated

Sanderson, M. A., C. A. Rotz, S. F. Fultz, and E. B. Rayburn. 2001. Estimating forage mass with a commercial capacitance meter, rising plate meter, and pasture ruler. Agron. J. 30:1281-1286.