The impact of tomato pomace silage on feed utilization, health status, milk yield, and composition in dairy cows

The aim of this study was to evaluate the effect of the inclusion of tomato pomace silage (TPS) on feed intake, nutrient digestibility, blood parameters, immune response, milk yield, and composition in dairy cows.

Sixteen Thai Holstein dairy cows with a mean body weight of 621±20 kg and 240±15 d in milk were randomly assigned to a completely randomized design. The TPS was added at 0%, 10%, 20%, and 30% dry matter (DM) in a fermented total mixed ration. Each cow was given the diet ad libitum.

The nutrient intake was similar among treatments except for ether extract intake, which increased linearly (p<0.01) with the addition of TPS. The inclusion of TPS at 20% and 30% linearly increased the digestibility of organic matter, crude protein, and ether extract (p≤0.01). The addition of TPS did not affect the blood chemicals or hematology except for monocytes, which increased cubically (p<0.05) when TPS were added. The immune function (IgA, IgM, and IgG) did not change with added TPS. There was no difference in milk yield and milk composition among treatments. Vitamin A and vitamin E in milk marginally elevated (p<0.01) by increasing levels of TPS. The inclusion of TPS increased the oleic acid (C18:1 cis-9), linoleic acid (C18:2 cis-9,12+trans-9,12), and α-linolenic acid (C18:3 cis-9,12,15) in milk (p<0.05). The unsaturated fatty acids and monounsaturated fatty acids in milk increased linearly (p<0.05) in cows fed TPS, but TPS did not impact polyunsaturated fatty acids.

The inclusion of 30% (on a DM basis) of TPS in the diets enhanced the digestibility of nutrients, milk vitamins, and milk fat (unsaturated fatty acids) without affecting the feed intake, blood parameters, or milk yield in late-lactating dairy cows.