Molecular structure, chemical and nutrient profiles, and metabolic characteristics of the proteins and energy in new cool-season corn varieties harvested as fresh forage for dairy cattle

Abstract

To our knowledge, no previous research exists concerning the molecular structure and metabolic characteristics of the proteins and energy that new cool-season corn varieties provide for dairy cattle. The objectives of this study were to identify the differences in the molecular structures of proteins among several new cool-season corn varieties [Pioneer P7443R, Pioneer P7213R, Pioneer P7535R (Pioneer Hi-Bred International Inc., Johnston, IA), Hyland Baxxos RR, Hyland SR22, and Hyland SR06 (Hyland Seeds, Blenheim, ON, Canada)] using Fourier transform infrared attenuated total reflectance (FT/IR-ATR) molecular spectroscopy, and to determine the nutrient profile and supply that each variety provided for dairy cattle. The protein molecular structure studies showed that the amide I to amide II ratio ranged from 1.09 to 1.66 and that the α-helix to β-sheet ratio ranged from 0.95 to 1.01 among the new cool-season corn varieties. Energy content was significantly different among the new varieties. We found significant differences in the protein and carbohydrate subfractions and in the ruminal degradation kinetics of the organic matter, crude protein, starch, and neutral detergent fiber of the new varieties. The new varieties had similar estimated intestinal digestibilities for rumen undegraded crude protein. However, the new varieties had significant differences in predicted total truly absorbable protein, ranging from 39 to 57 g/kg of dry matter, indicating that these newly developed varieties are satisfactory sources of truly absorbed protein for dairy cattle. Further study on the molecular structure profiles of cool-season corn in relation to its nutrient utilization and availability in dairy cattle is necessary.

Evaluation of Low Heat Unit Corn Hybrids Compared to Barley for Forage Yield and Quality on the Canadian Prairies

“…The 3 corn hybrids were only adequate in the CP for cows in the mid-gestation stage. Therefore, cows in the late pregnancy stage grazing these corn hybrids (regardless of grown site and of fertility sources) would consequently need some form of protein supplementation (Van De Kerckhove et al, 2011;Jose, 2015;Damiran et al, 2016), or good legume hay (Krause et al, 2013) (Abeysekara et al, 2013) and are in close agreement with our current results.…”

“…Protein content was higher for barley (10.3 to 14.3% CP) than the 3 corn hybrids (6.8 to 9.3% CP). The latter CP values were in agreement with those of previous work (Baron et al, 2003;Abeysekara et al, 2013) for corn forage. Taking into consideration the protein requirements of beef cattle, in the current study, only AC Ranger barley had sufficient amounts of CP required by gestating and lactating cows.…”

“…The corn grown in the Canadian prairies is different from the corn hybrid varieties grown in warmer climates (Lassiter et al, 1958). The main differences are due to the shorter growing season and lower growing temperatures in the Canadian prairies compared with the areas of warm-season corn production, such as the United States (Lauer et al, 2001;Abeysekara et al, 2013). Many corn hybrids for western Canada requireRecently, with the introduction of low heat unit corn hybrids [i.e., Pioneer P7443R (Pioneer Hi-Bred International Inc., Johnston, IA), Hyland 2D093 (Hyland Seeds, Blenheim, ON, Canada), Monsanto DKC26-25 (Monsanto Creve Coeur, Greater St. Louis, Missouri] suited to western Canadian weather, there is an increased interest in the use of warm season annuals in extensive grazing systems Jose, 2015).…”

Using vibrational infrared biomolecular spectroscopy to detect heat-induced changes of molecular structure in relation to nutrient availability of prairie whole oat grains on a molecular basis

“…Intestinal protein digestibility (IVCPD) was determined according to the modified in vitro method of Calsamiglia and Stern [25–27]. Briefly, dried ground rumen residues containing 15 mg of N after 16 h of ruminal incubation were exposed for 1 h to 10 mL of 0.1 N HCl solution containing 1 g of pepsin/L.…”

Evaluation of Barley Silage with Varying Ruminal In Vitro Fiber Digestibility on Lactation Performance and Chewing Activity of Lactating Dairy Cows in Comparison with Corn Silage

“…The corn grown in the Canadian prairies is different from the corn hybrid varieties grown in warmer climates such as United States (Abeysekara et al 2013a(Abeysekara et al , 2013b). These differences are attributed to some limitation during growing season (i.e., lower growing temperatures).…”