There are limited trials using tomato crop residues in ruminants and it is thus difficult to conclude on the utilization of such a material. They should be preferably used dried or ensiled rather than fresh due to pesticide residues that can be transferred into milk. Pesticide residues remain the main potential problem with those products. Tomato plants (stem+leaves) are traditionally used to feed sheep and dairy cows in Costa Rica (Rodriguez-Campos et al., 2014, unpublished).
Toxicology
No adverse effects have been reported so far on ruminants consuming such plants. However, glycoalkaloids have several effects on cells development (Milner et al., 2011). It is thus advised not to feed pregnant females with tomato plants. Because of possible pesticide residues contamination in fresh tomato plants, it is recommended not to feed dairy animals with fresh tomato haulms. Drying and ensiling were reported to effectively reduce pesticide residues in the plant: pesticide residues almost disappeared in milk from dairy animals fed on dried or ensiled materials (Ibrahim et al., 2020; El-Sayed et al., 2012). Though some toxic level of nitrates have been reported in dry tomato leaves, there were no negative effect on beef cow health (Shlosberg et al., 1996).
Degradability
The in sacco CP degradability of whole tomato plant is low (20%) to medium 42-44 % (Ventura et al., 2009; El-Sayed et al., 2012). In an in sacco experiment in lambs, it was shown that tomato shrub had 17% crude soluble protein, 21% fermentescible protein and 79% (the highest) metabolizable protein in comparison with potato, melon, and strawberry shrubs. It was concluded that it could be used in the supplementation of lambs (Moghaddam et al., 2017). Whole tomato plant has a low in sacco organic matter digestibility (OMD) ranging from 33 % to 41.4 % (Ventura et al., 2009; El-Sayed et al., 2012).
Dairy cows
In Egypt, feeding dairy cows (550 kg) with fresh or dried tomato haulms with the same amount of concentrate did not affect milk yield (11.1 – 11.5 kg/d), but ensiling tomato haulms with fungus or yeast increased milk yield up to 15 kg/d without altering milk composition (El-Sayed et al., 2012).
Growing fattening cattle
In Israel, dried tomato vines , replacing wheat straw in beef cow diets did not cause health problems and did not alter body weight (Shlosberg et al., 1996).
Dairy goats
In Egypt, in dairy goats fed with fresh or ensiled tomato haulm prepared with molasses or bacteria, milk yield, fat and protein content were higher with silages and much higher with bacteria as additive (Ibrahim et al., 2020).
