Controlled trial reveals protein but not methionine supplementation improves beef cattle performance, indicating extra amino acid offers limited late-gestation benefit.
Key Points
To evaluate the effects of supplemental methionine during late gestation on feed intake, maternal body weight, reproductive performance, and calf carcass characteristics in beef heifers and cows.
Conducted two 3-year trials: Exp. 1 evaluated 113 pregnant Black Angus crossbred heifers fed hay alone, dried distillers' grains (0.9 kg/d), or dried distillers' grains with 30 g/d methionine hydroxy analog.
Exp. 2 evaluated 436 pregnant Red Angus crossbred cows grazing winter range receiving no supplement, ad libitum hay, distillers'-based cubes (0.45 or 0.9 kg/d), or cubes (0.9 kg/d) with 30 g/d methionine hydroxy analog.
In Exp. 1, heifers supplemented with dried distillers' grains with or without methionine had significantly higher final body weight and average daily gain than unsupplemented heifers (P < 0.01), with similar hay intake (P = 0.38).
In Exp. 2, unsupplemented cows exhibited lower body condition scores (P < 0.01) and significantly lower pregnancy rates (80%) compared to supplemented groups (94% to 95%, P < 0.01).
Methionine supplementation conferred no additional significant benefits for dam body condition, reproductive performance, or progeny carcass characteristics across both experiments.