112 Mineral supplement intake by weaned steers as affected by offering multiple salt sources

Abstract

Pastured cattle are sometimes offered multiple separate salt (NaCl)-containing nutritional supplements. This study objective was to determine how range meal presence impacts mineral supplement intake when cattle choose between multiple salt source offerings. Weaned Bos taurus crossbred steers (n = 24) (initial BW = 263 ± 4.0 kg) were stratified by BW in a completely randomized design across 4 pens with 2 GrowSafe bunks per pen with ad libitum access to mixed-grass pasture and 1) one bunk supplied with a mineral supplement containing 15.0% salt (Grazer Hi/Se Hi/Cu CTC 2800; Multi-Kare, Inc., Tifton, GA) (MINERAL) or 2) one bunk containing a 2:1 range meal containing 30% salt and 13% CP (HI-GRAIN RANGE MEAL 1–2; Land O’Lakes Purina Feed LLC, Shoreview, MN) and the other bunk containing the mineral supplement (RM2) (Exp. 1). In Exp. 2 the 2:1 range meal was replaced with a 3:1 range meal containing 22.5% salt and 15% CP (HI-GRAIN RANGE MEAL 1–3; Land O’Lakes Purina Feed LLC, Shoreview, MN) (RM3). After a 14-d acclimation period intake was monitored for 42 days for Exp. 1 followed by a 7-d acclimation and Exp. 2 spanning 42 days. Mean daily DMI per steer were 104.6 ± 22.7 g and 525.8 ± 228.0 g of the 2:1 and 3:1 range meal, respectively. In Exp. 1 steer daily DMI was greater (P < 0.01) for MINERAL (31.9 ± 2.2 g) than for the mineral portion (4.3 ± 2.2 g) of RM2. Mean steer daily DMI in Exp. 2 was greater (P < 0.01) for MINERAL (57.2 ± 6.1 g) than the mineral portion (3.4 + 6.1 g) of RM3. Range meal offered separately and simultaneously with a salt-containing mineral supplement decreases mineral supplement consumption by severalfold with implications for potential inadequate daily intake of nutrients and medications mixed in these supplements.