Short communication: Kelp taste preferences by dairy calves.

Kelp is a common feed additive used on many dairy farms in the United States. However, few data are available supporting the efficacy of its addition to cattle feed. The purpose of this study was to evaluate the taste preferences of calves provided with 0, 30, or 60 g of kelp daily in a sequential elimination experiment. Calves in this study always ranked the control treatment first when given a choice and consumed 34.5% more dry matter from the control treatment in the first 3-d segment of the experiment. During the second feeding segment (d 4 and 5), when the control treatment was removed, daily dry matter consumption was reduced in 4 out of 6 calves compared with control calves when this treatment was available (first feeding segment). However, calves did not differentiate between the 2 amounts of kelp. Results indicated that calves preferred calf starter grains without kelp.

Ionophore taste preferences of dairy heifers.

Two taste preference studies were conducted using six Holstein heifers in each experiment to determine preferences for no ionophore, lasalocid, or monensin in the diet. In Exp. 1, individually penned (approx. 5 mo old; 220 +/- 14 kg BW) heifers were fed a basal total mixed ration containing 46% corn silage, 46% grass haylage, and 8% soybean meal (DM basis). There were five treatments (mg/kg BW(-1)*d(-1)): 0 ionophore (control), 1 lasalocid (1L), 2 lasalocid (2L), 1 monensin (1M), or 2 monensin (2M). Ionophores were provided as part of the mineral mix that had been added to the control diet and through an ionophore-grain by-product mix to make the 2L and 2M treatments. All five diets were offered for 7 d, with the first 2 d for adaptation and the last 5 d for measurement of feed intake. The most preferred diet was then removed and the study continued with the four remaining diets. The most preferred diets were again eliminated sequentially, so that only two diets remained on d 13 and 14. Each feeding segment ranking of treatment preferences was determined based on the weight of feed refused at the end of each feeding segment. In Exp. 2, six 6-wk-old heifers (75 +/- 5 kg of BW) were individually fed either 0, 1L, or 1M in a study similar to Exp. 1, except that the most preferred diet was removed after 4 d, with the first day for adaptation and the last 3 d for measurement of feed intake. In Exp. 1, orthogonal contrasts indicated that heifers preferred the 1L and 2L diets over the 1M and 2M diets. Preferences between diet concentrations of ionophores (1 and 2 mg/kg of BW; Exp. 1) and the control and ionophore treatments did not differ, nor was there an interaction between ionophores and their concentration. Dairy heifers previously fed lasalocid prefer lasalocid over monensin when given a choice; however, heifers without previous exposure to an ionophore did not indicate a preference (Exp. 2).

Dietary preferences in early lactation cows as affected by primary tastes and some common feed flavors.

A sequential elimination trial was conducted to test the effects of primary tastes on the preference ranking of TMR diets by six multiparous Holstein cows from 8 to 21 DIM. Four additives and a control were examined; the most preferred (highest total intake) was eliminated after segments of 5, 4, 3, and then 2 d. Diets tasting sweet (sucrose, 1.5% of dietary DM), sour (HCl, 1.25%), bitter (urea, 1%), and salty (NaCl, 4%) were tested. Four of the cows most preferred the sweet diet, and DMI of that diet averaged 12.8% more than for the control, which was next preferred. The probability of a diet being chosen first when all diets were presented together was sucrose, .59; control, .36; urea, .04; NaCl, .01; and HCl, .003. Another experiment used the same procedure; however, the additives tested were anise, monosodium glutamate, dehydrated alfalfa meal flavor, and molasses flavor (1.48 g of flavor/kg of DM). Control and monosodium glutamate ranked first equally. The probability of choosing each flavor first in this set was .5 for the control and monosodium glutamate diets and < .01 for molasses, alfalfa, and anise. Rankings were not significantly affected by variation among cows in either experiment. Of the additives tested, only sucrose seemed to have the potential to increase intake.