Palatability of total mixed ration containing propanediol mononitrate

Abstract

The objective of this proposal is to evaluate the effect of propanediol mononitrate (PDMN) inclusion in the diet of dairy cows on dry matter and nutrient intake, milk production and composition. The experiment will be conducted in the tie-stall barn of Penn State's Dairy Center with 12 cows at various lactation stages; between 60 and 120 days in milk. Cows will be simultaneously receiving 2 rations - one without PDMN (control) and another with PDMN included at 30, 60, 90, or 120 ppm, feed DM basis. The experiment will have 4 phases/periods (Period 1: control and PDMN at 30 ppm; Period 2: control and PDMN at 60 ppm; Period 3: control and PDMN at 90 ppm; Period 4: control and PDMN at 120 ppm). During the experimental periods, feeding will be 3 times/daily - at approx. 8AM, at 4PM, and at 2AM. Each period will last for 3 d and there will be a 3 day break between periods. Feed offered and refused will be recorded daily. Samples from both control and PDMN TMR will be collected for DM and chemical analysis throughout the experiment. Intake of feed DM will be estimated based on feed intake and DM of the TMR. Aliquots of the TMR samples will be analyzed for PDMN concentration. Milk production and BW of the cows will be recorded throughout the experiment. Milk samples for composition analyses will be collected twice during the study. All data will be analyzed using SAS software (version 9.4, 2013; SAS Institute Inc., Cary, NC), using the MIXED procedure of SAS. (AU)