Beet molasses is a highly palatable source of energy for ruminants. It is commonly used in mixture with straw or other fibrous feeds, as a binder, and to promote the ingestion of unpalatable feeds. The flavour and odour of beet molasses stimulate the appetite and promote digestion. Diets containing beet molasses have higher DM digestibility, increased levels of microbial nitrogen in the small intestine and high efficiency of microbial nitrogen synthesis Nitrogen supply by molasses may play an important role in increasing the ingested quantities of the medium-quality diets into which they are generally integrated (CNC, 2002; Harland et al., 2006).
Due to the high sugar and potassium content of beet molasses, there should be a 8-10 days transition period before feeding significant amounts of molasses to ruminants. Livestock should be provided with mineral licks, and with additional bedding material due to the laxative effects of molasses (CNC, 2002). When a significant level of beet molasses is fed to cattle, a proportion of the diet needs to be in the form of roughage to facilitate rumen outflow and limit digestive disorders (CNC, 2002; Harland et al., 2006). When given with energy-rich diets, beet molasses should not exceed to 10% of the DM intake.With diets based on coarse fodder, molasses can be included at up to 15-20% of DM intake (CNC, 2002). Feeds rich in potassium (beet leaves and collars, chicory roots, whey, potatoes...) should be avoided (CNC, 2002).
Dairy cows
In dairy cows, beet molasses can be included without adverse effect at levels of 10-15% diet DM (Harland et al., 2006). In France, recommendation for dairy cows is 2-3 kg/d (CNC, 2002). Higher levels are possible if long forage is provided but such levels may give a fishy taste to the milk, due to the breakdown of betaine to triethylamine (Harland et al., 2006). Very high inclusion levels of beet molasses (50% diet DM, about 6 kg of molasses) are not recommended because they induce butyrate production in the rumen, causing ketosis and resulting in a 20-45% decrease in milk production (Bernard et al., 1991).
Beef cattle
Up to 20% beet molasses can be included in both forage and mixed diets of beef cattle with no adverse effect on growth and performance (Harland et al., 2006). In France, it has been recommended to give beef cattle 0.25 to 0.5 kg/d of molasses for animals of 200 kg liveweight, and 1-2 kg/d for heavier livestock (CNC, 2002). In Chile, with 400 kg steers fed from 0.6 to 2.4 kg beet molasses per 100 kg of liveweight daily, there were no adverse effects on health even at the highest levels of inclusion. Performance in terms of liveweight gain improved as the proportion of molasses in the diet increased (Ruiz et al., 1980). However, higher butyrate concentration may lead to the production of ketone bodies and decrease the efficiency of energy utilization for growth and fattening. The inclusion of urea in the diet may enhance propionate production and decrease the levels of ketogenic and higher volatile fatty acids, leading to a more efficient utilization of beet molasses for fattening (Harland et al., 2006).
Sheep
Molasses can replace some of the cereals in sheep diets. Molasses intake should be limited to 0.6 kg/d for ewes and to about 0.2 kg/d for 30 kg lambs. Mineral licks should be provided. Spraying molasses on poor quality fodder increases the quantities ingested because of its palatability. However, sheep may search through the fodder to reach the molasses, which sticks around the eyes, collecting dust and causing eye problems (CNC, 2002). In a trial in Ireland, feeding up to 9% molasses to early-weaned lambs did not affect growth rate but reduced feed intake at the higher level of molasses inclusion. The main issue was that the inclusion of molasses at 6–9% decreased the cleanliness of fleeces below levels acceptable by abattoirs (Boland et al., 2004).
Goats
Molasses can be sprayed on roughage-based goat diets to make them more palatable (CNC, 2002).