1) A administração de caseína iodada aumentou a produção de leite, nos três níveis ensaiados, sendo os aumentos de 37,9%, 29,8% e 31,2%, respectivamente, para as doses diárias de 10, 15 e 20 gramas do produto.2) O aumento observado na produção de gordura foi decorrente da maior produção de leite, não se evidenciando aumento percentual da matéria gorda.3) Houve perda de pêso nos lotes tratados com 15 e 20 gramas de tiroproteíria até a 6a semana experimental, passando os animais a partir de então a recuperar-se e terminando o período experimental com pêso igual ou superior ao início do experimento. O grupo de 10 gramas apresentou ganho de pêso durante o experimento.4) Os animais dos tratamentos 15 e 20 gramas de caseína iodada apresentaram sensível aumento nas freqüências cardíacas e respiratória, as quais voltaram à normalidade no fim do experimento.

Twelve milking cows were randomized in four groups of three cows each and fed during the winter with iodinated case on the levels of 0, 10, 15 and 20 grams daily. During the experiment daily milk weights were recorded and individual milk samples were taken twice monthly for butterfat test by Gerber method. Body weights, heart rates, respiration and temperature were determined twice monthly.The increase in milk production on 10 grams of iodinated case was 37,9 per cent, on 15 grams, 29,8 per cent and on 20 grams, 31,2 por cent.The butterfat production was higher as a decurrence of increase in milk production not as a percentual increase in milk fat.No collateral effects were observed on 10 grams level of iodinated case while on the 15 and 20 grams levels increase in heart and respiration rates as well a: loss in body weight were recorded during the first 6 weeks. After these first, weeks weight gains were resumed and heart, respiration and body weight returned to normal.