Abstract #M15

# M15
Automatic feed push-up frequency effects on dairy cattle behavior and milk production.
Michelle D. Adamczyk1, Lori N. Grinter*1, Amanda R. Lee2, Jeffrey M. Bewley3, Joao H. C. Costa1, 1Dairy Science Program, Dept. of Animal and Food Sciences, University of Kentucky, Lexington, KY, 2Department of Animal Science, University of Tennessee Knoxville, Knoxville, TN, 3CowFocused Housing, Bardstown, KY.

Feed push-up improves the feed availability for dairy cows between feed deliveries and may increase intake and milk production. The study objective was to compare the effects of different feed push-up frequency of an automatic feed push-up system (Juno, Lely, Maasluis, Netherlands) on dairy cow behavior and milk production. Forty-eight cows (mean ± SD; 173 ± 101 DIM; 73.6 ± 23.3 lbs/d; 1.3 ± 0.5 parity) were divided into 2 groups, balanced by parity and DIM. A crossover design compared 2 treatments from April to June 2017: 2 feed push-ups/d (2FPU; 1000 and 1950 h) and 12 feed push-ups/d (12FPU; 0000, 0200, 0345, 0500, 0820, 1000, 1200, 1400, 1610, 1950, 2100, and 2200 h), for 3 wk/treatment, separated by 1 wk washout. Rumination time and eating time were measured by a behavior monitoring eartag; SmartBow (SmartBow GmbH, Jutogasse, Austria) and SensOor (Agis Harmelen, the Netherlands) respectively. Rest time was recorded by a behavior monitoring leg tag (Afi Act II, Afimilk, Afikim, Israel). An in-line milk assessment tool (AfiLab, Afimilk, Afikim, Israel) measured milk yield, milk fat percentage, and protein percentage. A mixed linear model (SAS 9.4) was used to determine the relationship of feed push-up frequency with behavior and milk production variables. Date was specified as a repeated measure, and cow as subject, using a compound-symmetry structure. The model contained the fixed effects of DIM, parity (1 or 2), treatment, sequence of treatment, THI, and all 2-way interactions (fixed effects remained regardless of significance; manual backward elimination removed non-significant 2-way interactions). Daily resting time was greater for 2FPU than 12FPU (640 ± 12 vs 615 ± 12 min/d; P < 0.001) and rumination tended to increase for 2FPU (366 ± 9 vs 359 ± 9 min/d; P = 0.06). Daily eating time and energy corrected milk were not different between treatments (P > 0.10). Feed push-up frequency influenced cattle behavior; however did not have a significant effect on feeding or production. Further research with feed push up frequency should consider intermediary frequencies and other variables as intake rate and feeding bouts.

Key Words: feed availability, push-up frequency, precision dairy technology