Effects of Feeding Silage and Grain from Glyphosate-Tolerant or Insect-Protected Corn Hybrids on Feed Intake, Ruminal Digestion, and Milk Production in Dairy Cattle,

Abstract

Lactating dairy cows were used to determine effects of feeding glyphosate-tolerant or insect-protected corn hybrids on feed intake, milk production, milk composition, and ruminal digestibility. Corn resistant to European corn borer (Ostrinia nubilalis) infestation (Bt-MON810), or its nontransgenic control (Bt-CON), were planted in alternating fields during two successive years. One-half of each strip was harvested for whole plant corn silage and the remainder was allowed to mature and harvested as grain. Effects of feeding diets containing either Bt-MON810 or Bt-CON grain and silage were determined in two experiments (1 and 2) conducted during successive years. In experiment 3, glyphosate-tolerant Roundup Ready corn (RR-GA21) or its nontransgenic control (RR-CON) corn were grown in alternating fields during one cropping season. Diets contained 42 to 60% corn silage and 20 to 34% corn grain from Bt-MON810, RR-GA21, or the appropriate nontransgenic counterpart; treatments were applied using a switchback design. Cows were fed ad libitum and milked twice daily. There were no differences for nutrient composition between silage sources or between grain sources within an experiment. Data for experiments 1 and 2 indicated similar dry matter intake (DMI), 4% fat-corrected milk (FCM) production, and milk composition between Bt-MON810 and Bt-CON diets. There were no differences for DMI, 4% FCM production, and milk composition between RR-GA21 and RR-CON diets. There was no difference in ruminal degradability, determined separately for corn silage and corn grain, for RR-GA21 or Bt-MON810-hybrids compared with their respective controls. These data demonstrate equivalence of nutritional value and production efficiency for corn containing Bt-MON810 compared with its control and for RR-GA21 corn compared with its control.

Effect of feeding glyphosate-tolerant (Roundup-Ready events GA21 or nk603) corn compared with reference hybrids on feedlot steer performance and carcass characteristics1

“…Lack of differences among treatments observed in all three experiments agrees with previous research evaluating glyphosate-tolerant corn and soybeans fed to dairy cattle (Donkin et al, 2003;Hammond et al, 1996), pigs (Cromwell et al, 2001;Stanisiewski et al, 2001;Gaines et al, 2001a), and poultry (Gaines et al, 2001b;Taylor et al, 2003). Donkin et al (2003) utilized silage and grain from Roundup Ready corn (event GA21) to examine effects of transgenic crops on feed intake, milk yield, and milk composition for sixteen lactating Holstein cows.…”

Effects of Feeding Calves Genetically Modified Corn Bt11: A Clinico-Biochemical Study

“…Consequently, the Cry toxin has become a genetic resource for developing insect-resistant, genetically modified (GM) plants including Bt11 [2]. Before the introduction of Bt11 corn, there were several studies to assess its safety based on livestock performance [1,4,5]. However, there is little knowledge available on the clinicobiochemical effects of feeding Bt11 to cattle.…”

Safety Evaluation of Bt Plants

“…Effects of Bt corn on rumen functions that play an important role in digestion and absorption were also examined, and ruminal pH, acetate: propionate ratio, in situ digestion kinetics of NDF (neutral detergent fiber), efficiency of milk production, and daily body weight gain were unaffected by the transgenic corn 22 . Other feeding studies also demonstrated the equivalence of nutritional value of Bt corn and productivity of animal products from cattle fed Bt corn, compared with its nontransgenic control 18,23,58 . Additionally, the results of some compositional analyses and feeding studies of Bt cotton indicated that transgenic cotton is substantially equivalent to its non-transgenic control, similar to Bt corn 8,25 .…”