Performance of dairy cows fed silage and grain produced from second-generation insect-protected (Bacillus thuringiensis) corn (MON 89034), compared with parental line corn or reference corn

Abstract

Corn grain and corn silage are major feed components in lactating dairy cow rations. Bacillus thuringiensis (B.t.) is a naturally occurring soil bacterium that produces a protein that is toxic to lepidopteran insects that may damage plant tissues and reduce corn quality and yields. During each of the four 28-d periods, cows were offered 1 of 4 rations in which the corn grain and silage originated from different corn hybrids: a nontransgenic corn control (from hybrid DKC63-78; Monsanto Co., St. Louis, MO), a B.t. test substance corn (MON 89034 in hybrid DKC63-78; Monsanto Co.), and 2 commercial nontransgenic reference (Ref) hybrids: DKC61-42 (Ref 1) and DKC62-30 (Ref 2; Monsanto Co.). Sixteen multiparous Holstein cows averaging 110 ± 21 d in milk and weighing 684 ± 62.3 kg were blocked by days in milk and milk yield and randomly assigned to one of four 4 × 4 Latin squares. Diets were formulated to contain 36.4% corn silage and 16.3% corn grain. Dry matter intake was greater for cows consuming B.t. corn (26.6 ± 0.59 kg/d) compared with the control, Ref 1, and Ref 2 corn diets (25.4, 25.0, and 25.6 ± 0.59 kg/d, respectively). Milk yield, fat yield, and percentage of fat (36.8 ± 0.98 kg/d, 1.22 ± 0.05 kg/d, and 3.3 ± 0.10%), milk protein yield and percentage of protein (1.11 ± 0.03 kg/d and 3.01 ± 0.05%), milk urea nitrogen concentration (14.01 ± 0.49 mg/dL), and 3.5% fat-corrected milk yield (35.7 ± 1.07 kg/d) were not different across treatments. The results from this study show that lactating dairy cows that consume B.t. corn (MON 89034) do not differ from lactating dairy cows that consume nontransgenic corn in milk yield, 3.5% fat-corrected milk per unit of dry matter intake, or milk components.

Effects of whole-plant corn silage hybrid type on intake, digestion, ruminal fermentation, and lactation performance by dairy cows through a meta-analysis

“…Genetically modified hybrids were compared with their genetically similar nonbiotech counterpart (ISO). Four trials compared a GM hybrid against 2 commercial hybrids in addition to the genetically similar non-biotech counterpart (Grant et al, 2003;Ipharraguerre et al, 2003;Phipps et al, 2005;Castillo-Lopez et al, 2014), and one trial compared CON versus GM at both early and late maturity in 2 trials (Folmer et al, 2002). Thus, the larger sample size for CON than GM hybrids (21 versus 13, respectively).…”

Effect of maturity stage at harvest on the ensilability of maize hybrids in the early and late FAO classes, grown in areas differing in yield potential

“…Maize ( Zea mays , L.) silage represents one of the most important forages used for dairy cow feed and beef cattle rations in temperate regions (Grant & Adesogan, ; Marchesini, Serva, Garbin, Mirisola, & Andrighetto, ), owing to its high productivity, ease of ensiling and nutritional profile, including both starch and physically effective fibre (Grant & Ferraretto, ; Khan, Yu, Ali, Cone, & Hendriks, ). For these reasons, it is often included in rations at over 30%–40% of dry matter (DM) and over 50% of a ration's fodder (Castillo‐Lopez et al, ; Grant & Adesogan, ; Silva et al, ).…”