Effects of calcium montmorillonite clay and aflatoxin exposure on dry matter intake, milk production, and milk composition

Authors: MAKI, CODY - Texas A&M University; THOMAS, ASHLEY - Tarleton State University; ELMORE, SARAH - Texas A&M University; ROMOSER, AMELIA - Texas A&M University; Harvey, Roger; RAMIREZ, HUGO - Tarleton State University; PHILLIPS, TIMOTHY - Texas A&M University

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/5/2015
Publication Date: 2/1/2016
Publication URL: http://handle.nal.usda.gov/10113/62688
Citation: Maki, C.R., Thomas, A.D., Elmore, S.E., Romoser, A.A., Harvey, R.B., Ramirez, H.A., Phillips, T.D. 2016. Effects of calcium montmorillonite clay and aflatoxin exposure on dry matter intake, milk production, and milk composition. Journal of Dairy Science. 99(2):1039-1046.

Interpretive Summary: Aflatoxin (AF) is a toxin produced by fungi that can cause disease and cancer in animals and humans. AF residues are readily transferred into cow’s milk, and AF residues in milk are stringently regulated, prompting the destruction of milk that is above acceptable levels. This costs the dairy industry millions of dollars annually. Twenty-five years ago, researchers at ARS and Texas A&M University, College Station, TX, discovered a compound (NovaSil) that reduced passage of AF into the milk; however, it was not adopted by the dairy industry because it was unknown about potential side effects on cows, milk production, or milk composition. The present study showed that cows fed AF and NovaSil had reduced AF in milk, yet there were no differences in milk production or composition between control cows and those consuming NovaSil. This is important because it will allow the dairy industry to utilize NovaSil without affecting milk production, but it also assures that the nutrition, wholesomeness, and safety of milk is preserved.

Technical Abstract: Fifteen primiparous crossbred dairy cows that were 114 ± 14 d in milk and weighed 533 ± 56 kg were used in a replicated 5×5 Latin square to test the efficacy of NovaSil Plus (NSP) for the reduction of aflatoxin (AF) metabolite (AFM1) in milk and the effect of NSP on milk composition. Cows were housed in a free-stall barn, fed once a d and milked twice a d. The experiment consisted of five 14 d periods: d 1 through 7 were considered for data collection, and d 8 through 14 were considered a wash-out phase. In each period, cows were randomly assigned to 1 of 5 dietary treatments: 1) control (CON), consisting of a basal total mix ration (TMR); 2) high dose NSP diet (NSP-1%), consisting of TMR plus 230 g of NSP; 3) aflatoxin diet (AFD), consisting of the TMR plus AF challenge; 4) low dose NSP with AF (NSP-0.5%+AFD), composed of TMR plus 115 g of NSP and AF challenge; 5) high dose NSP with AF (NSP-1%+AFD), consisting of TMR plus 230 g of NSP and AF challenge. The AF challenge consisted of top-dressing a daily dose of 100 µg/kg estimated dry matter intake (DMI), similarly, NSP was fed at 1.0 or 0.5% of estimated DMI. Milk yield and DMI were similar across treatments averaging 21.1 ± 1.33 kg/d and 19.7 ± 0.56 kg/d, respectively. Concentration of milk fat, protein, and lactose were similar across treatments with averages of 4.91 ± 0.20%, 3.85 ± 0.10%, and 4.70 ± 0.06%, respectively. Concentration of vitamin A averaged 0.28 ± 0.03 µg/mL and riboflavin concentration averaged 1.57 ± 0.13 µg/mL across treatments. The concentration of minerals in milk were similar for all treatments. Cows fed CON and NSP-1% yielded the lowest concentration of AFM1 in milk with 0.03 and 0.01 ± 0.06 µg/L. Addition of NSP reduced milk AFM1 from 1.10 ± 0.06 µg/L with the AF diet to 0.58 and 0.32 ± 0.06 µg/L with the NSP-0.5%+AF and NSP-1%+AF diets, respectively. Excretion of AFM1 was reduced by NSP; mean values were 24.38, 11.86, 7.38, 0.64, and 0.23, ± 1.71 µg/d, for AFD, NSP-0.5%+AFD, NSP-1%+AFD, NSP-1%, and CON, respectively. More specifically, 1.07 ± 0.08% of the daily AF intake was transferred to the milk of cows consuming the AFD, whereas the AF transfer rates in milk from cows that consumed the NSP-0.5%+AFD and NSP-1%+AFD were 0.52 and 0.32 ± 0.08%. Results from this research demonstrate that feeding NSP to lactating cows is an effective method to reduce the transfer and excretion of AFM1 in milk with no negative effects on dry matter intake, milk production, and composition.