Whole plant corn silage (WPCS) is the most common forage used in diets for dairy cows worldwide with it typically making up 40-60% of the forage DM in the diet. Whole-plant corn silage normally has a relatively high energy content; however, energy availability depends on its quality. Short stature corn is a relatively new variety of corn that is speculated to have increased standability, be less of a lodging risk, and have potential for tighter seeding density. This study aimed to assess the physical properties of short stature corn, compared to conventional corn, at the time of harvest and evaluate the effects of organic acids on the nutritional quality and fermentation profile of the two corn varieties.
Research was conducted at the Center of Maryland Research and Education Center (Figure 1). Short stature (STC) and conventional corn (CC) plots were planted and harvested. Mini silos (1,000 g) were prepared at harvest using two corn types (STC, CC), two treatments (water control; CON vs. organic acids; ORG), and six storage times (0, 7, 15, 30, 60, 120 d), with five replicates (Figure 2). Both varieties were harvested at 32–35% DM. ORG treatment consisted of a commercial blend of propionic and acetic acid diluted in water; CON received water only. Silos were stored for designated durations and analyzed for particle size, fermentation end products, microbial counts, and nutrient composition.
The Penn State Box method is an essential tool for evaluating the particle size of dairy rations, a critical factor in balancing rations to meet cows’ nutritional needs. The process begins by collecting a representative sample (TMR from the feed bunk or corn silage at harvest). The particle size distribution was similar for conventional and short stature corn, indicating short stature can provide similar fiber components as conventional corn. It is essential to maintain particle size distribution, as observed with short stature corn compared to conventional corn, as particle size influences ration formulation based on physically effective fiber. It ensures proper fermentation once chopped corn is packed into a silo.
Additionally, at harvest, the DM was 32% and 34% for conventional and short stature corn, respectively. For individual components, the distribution for conventional and short stature corn (respectively) was 15% and 14% on the 19mm sieves, 58% and 56% on the 8mm sieves, 15% and 17% on the 4mm sieves, and 13% for both in the pan.