Evaluation of hay and silage in receiving diets of newly weaned calves over two years

Authors: BLOM, E - South Dakota State University; PRITCHARD, R - South Dakota State University; Hales Paxton, Kristin

Submitted to: Proceeding of Plains Nutrition Council Symposium
Publication Type: Abstract Only
Publication Acceptance Date: 3/21/2018
Publication Date: 3/28/2018
Citation: Blom, E.J., Pritchard, R.H., Hales, K.E. 2018. Evaluation of hay and silage in receiving diets of newly weaned calves over two years [abstract]. In: Proceedings of Plains Nutrition Council Spring Conference, April 5-6, 2018, San Antonio, TX. p. 110-111.

Interpretive Summary:

Technical Abstract: Silages are often viewed as less desirable feedstuffs in receiving diets offered to newly weaned calves. A two-year experiment was performed to determine the effects of oat forage harvested as either hay or silage from the same crop in receiving diets on cattle performance and diet mixing and integrity characteristics. Steer calves (year 1 n = 180, year 2 n = 210) were weaned and transported to the Ruminant Nutrition Center. The next morning, calves were processed and BW was collected and used to assign steers to 1 of 3 dietary treatments (6 reps/treatment in year 1; 7 reps/treatment in year 2). Treatment diets differed only in oat forage as the roughage source and included either oat hay (HAY), oat hay with added water (HAYW; water = 10% of HAYW diet DM), or oat silage (SIL). Cattle were weighed 14 to 16 d after the start of the experiment and on d 42. Bunk samples were collected during a single feeding in year 1 and during 2 feedings in year 2. Bunk samples were collected at both feed delivery and post-meal and were subjected to particle separation with a 0.5 in2 sieve. Particles captured in the sieve and those that passed through the sieve were considered larger particles and smaller particles, respectively. Due to an initial overestimate of oat silage DM in year 1, the SIL steers were offered less (8.00 vs. 8.96 and 9.06 lb; P < 0.01) feed than HAY and HAYW during the 14 d after arrival when DMI limits were programmed by management; however, cattle in year 2 did not differ in DMI. Regardless, there were no diet effects on ADG, but SIL fed calves had greater G:F (0.360 vs. 0.307 and 0.313) than HAYW and HAY early in the experiment. Cumulative DMI was less for SIL fed calves (12.66 vs. 12.90 and 13.24 lb) than HAY and HAYW, but ADG was not different among treatments (P = 0.28) resulting in increased G:F (0.222 vs. 0.207 and 0.207) for IL fed steers compared to HAY and HAYW fed steers. The HAY diet contained a lesser (P < 0.01) proportion of larger particles at delivery compared to HAYW or SIL. The change in proportion of larger particles from delivery to post-meal was greater (157 vs. 42%; P = 0.04) for HAY compared to SIL. The proportion of larger particles delivered to the bunk linearly increased (P < 0.01) and cumulative ADG linearly decreased (P < 0.01) as batch fraction increased. In conclusion, SIL had no adverse effects on the performance of newly weaned calves. Oat silage improved diet mixing and integrity measured as more uniformity throughout the batch and less change in uniformity from delivery to post-meal. These variations in diet mixing across a batch were not recognizable by visual appraisal, but can impact cattle performance as ADG was reduced (P = 0.01) as the proportion of larger particles delivered to the bunk increased.