Carrots are quite palatable and readily consumed by cattle. With an energy value only slightly lower than that of maize grain (on DM basis), carrots can be used as an energy source (Rust et al., 2008).
Dairy cows and young bulls may be fed up to 25 kg and 20 kg fresh carrots a day respectively (Morel d'Arleux, 1990). Steers could be fed up to 40% of the diet DM as carrots without deleterious effects (Rust et al., 2008). Due to their high content of fermentable sugars, fresh carrots should be combined with fibrous feeds to prevent acidosis, and should be introduced progressively in the diet (8-10 days). The mixture of carrots and concentrate feed should not exceed 50% of the diet DM and ad libitum consumption must be prevented (Morel d'Arleux, 1990).
In dairy cows, most trials involving carrots have studied the effects of ß-carotene on milk composition and reproductive performance. Prolonged use of carrots in the diets of dairy cows increases the caroten content of the milk, producing a yellow colour in the milk fat (Fuller, 2004).
Butter with an elevated carotene content and an optimum iodine value can be produced by feeding dairy cows with 10 kg/d of rapeseed and carrots. As only low amounts of highly unsaturated fat were added to the diet, no problems connected with rumen digestion were encountered. This feeding strategy shows a practicable way of producing high-quality butter in moderate climates independent from seasonal variations (Schreiner et al., 2006). Supplementation of dairy cows with 5 kg/d of fresh carrots during the winter feeding period increased the content of vitamin A in milk (Nalecz-Tarwacka et al., 2003). In dairy cows fed carrot silage, the ß-carotene levels in blood plasma and milk increased greatly (Nonaka et al., 1994). In an earlier trial, the replacement of 10 kg of fodder beets by the same amount of carrots resulted in a 43% increase in milk carotene. This effect was maintained after replacement of the carrots by sugar beet. Milk protein and milk fat were not affected by the substitutions (Maschkin, 1982).
Feeding high-yielding cows with a diet containing 10 kg of fresh carrots resulted in a significant improvement in reproductive performance: a decrease in the interval between calving and the first successful insemination (from 167-185 days to 110-171 days) and a decrease in the number of inseminations necessary for conception (from 1.8-2.7 to 1.0-1.8), thus increasing the calving rate (from 84.5 to 92%). Dairy performance (yield and fat content) was unchanged (Car, 1985).
Prolonged use of carrots in the diets of beef cattle may give a yellow colour to the carcass fat (Fuller, 2004). Ensiling culled carrots with hay was found to produce a high-quality stored feed for the wintering of growing cattle. Carrots and grass hay were ensiled together, stored in vertical silos, and compared to a bromegrass/alfalfa silage in a feeding trial using steers: the carrot/grass silage ensiled well and was accepted by the steers, and growth performance was similar for both silages (Laflamme, 1992).
Carrots are a good feed for ewes and can be used similarly to fodder beet. Fresh carrots fed at 27% of the DMI (3.3 kg/d during the last month of gestation and 5 kg/d during lactation) were well accepted by gestating and lactating ewes. It was also possible to increase the inclusion level up to 80% in ewes at maintenance. However, dietary protein should be monitored (Molénat et al., 1999).
Goats can be fed up to 2-4 kg/d of fresh carrots (Morel d'Arleux, 1990; Weidman, 2010).
In Egypt, carrot top hay replacing 50% of berseem hay in the diet of Rahmani sheep generally increased nutrient digestibility (Bassiouni et al., 1999).
Carrot juice residue
Carrot juice residue was found to have potential as a ruminant feed with an ME value of 14.1 MJ/kg DM and a crude protein content and DM rumen disappearance higher than those of beet pulp (Enishi et al., 2004).