Pine needles from ponderosa pine (Pinus ponderosa Lawson) consumed by cows during winter can cause abortions. Our study determined the nutritional impact of pine needles given to steers intraruminally. In Trial 1, 12 steers were given either grass hay alone (CONT), 15% pine needles (15PN), or 30% pine needles (30PN) substituted for hay, as fed basis. In Trial 2, a 4 X 4 Latin square design was used with 4 steers. Treatments were: (1) control-grass hay alone (CONT); (2) grass hay plus 454 g/day of cottonseed meal (CSM); (3) pine needles substituted for 40% (as fed basis) of the hay (PN); and (4) pine needles (40%) plus 454 g/day of CSM (PNCSM). In Trial 1, dry matter intake (DMI), fecal N, and DM digestibility were not affected by either 15PN or 30PN. N intake and N digestibility were reduced (P < 0.07) by 30PN. Fluid dilution rate (FDR) and fluid outflow rate (FOR) were depressed (P = 0.10) by 30PN. Total VFA and ruminal ammonia-N also were depressed by 30PN. In Trial 2, the PN treatment adversely affected DMI, N intake, and all digestibility coefficients, and elevated fecal N. FDR, FOR, and turnover time (TOT) were reduced by 40% PN. Total VFA were increased by PN, while ammonia-N concentrations were reduced. Cottonseed meal had few effects on rumen variables, and there were no CSM X PN interactions. We conclude that pine needles severely affect cattle nutrition, particularly N intake and digestibility and fluid rate of passage. Cottonseed meal, at 1 kg/day, does not ameliorate the adverse effects of pine needles. Fifteen to 30% pine needles in cattle diets appears to be the threshold level for toxic effects on ruminal fermentation. This material was digitized as part of a cooperative project between the Society for Range Management and the University of Arizona Libraries. The Journal of Range Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact lbry-journals@email.arizona.edu for further information. Migrated from OJS platform August 2020
Scholarly peer-reviewed articles published by the Society for Range Management. Access articles on a rolling-window basis from vol. 1, 1948 up to 5 years from the current year. Formerly Journal of Range Management (JRM). More recent content is available by subscription from SRM.