Impacts of increasing levels of salt on intake, digestion, and rumen fermentation with beef cattle consuming low-quality forages

• Published in: Journal of animal science 2024-01, Vol.102
• Main Authors: White, Hayley C, Davis, Noah G, Van Emon, Megan L, DelCurto-Wyffels, Hannah M, Wyffels, Samuel A, DelCurto, Timothy
• Format: Article
• Language: English
• Subjects: Animal Feed - analysis; Animal Nutritional Physiological Phenomena; Animals; Cattle - physiology; Diet - veterinary; Dietary Supplements - analysis; Digestion - drug effects; Eating; Female; Fermentation; Rumen - drug effects; Rumen - metabolism; Ruminant Nutrition; Sodium Chloride, Dietary - administration & dosage
• ISSN: 0021-8812; 1525-3163; 1525-3163
• DOI: 10.1093/jas/skae284

The objectives of this study were to evaluate the levels of supplemental salt on low-quality forage intake, water intake, dry matter (DM) digestibility, and rumen fermentation. Six ruminally cannulated, Angus crossbred heifers (14 mo of age; 449 kg ± 24 kg body weight [BW]) were used in a dual 3 × 3 Latin square design. The heifers were housed in individual stalls with 2 animals assigned to each treatment per period. Salt treatments were mixed into a protein supplement of 50% cracked corn and 50% soybean meal and fed at 0.3% of shrunk BW. Salt treatments consisted of 1) control, no salt (CON), 2) 0.05% of BW salt (LOW), and 3) 0.1% of BW salt (HIGH). Chopped, low-quality (CP = 7.4%; NDF = 64.2%), grass hay was used as the base ration and was provided daily at 120% of the average daily intake of the previous 3 d. Each period included a 14-d diet adaptation, 6 d of sample collection, 1 d collection of rumen fluid samples for ruminal and microbial profiles. Individual forage dry matter intake, water intake, and DM digestibility were measured during the 6-d collection period. Rumen pH, ammonia levels, and volatile fatty acid (VFA) concentrations were measured during the 1-d ruminal profile. Rumen DM and liquid fill were determined with a 5-h post-feeding rumen evacuation. Supplemental salt had no influence on forage intake (P = 0.19) expressed on a kg/d basis yet tended to decrease linearly (P = 0.06) with increasing levels of salt when expressed on a grams/kg BW basis. DM digestibility was not influenced by salt levels (P > 0.05), but DM fill tended to increase linearly with increasing salt levels (P = 0.06). Water intake and liquid fill, however, increased linearly with increasing levels of salt (P