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Forage and breed effects on behavior and temperament of pregnant beef heifers

Journal of Animal Science and Biotechnology 2013年第3期4卷 165-169页

作者： angela r mays Michael L Looper Benjamin C Williamson Kenneth P Coffey Wayne K Coblentz Glen E Aiken Charles F rosenkrans Jr Department of Animal Science University of ArkansasFayetteville AR 72701 USA Department of Agricultural Sciences Morehead StateUniversity327 Reed Hall Morehead KY 40351 USA USDA-ArS US Dairy Forage Research CenterMarshfield WI 54449 USA USDA-ArS Forage Animal Production Research UnitLexingtonKY 40546 USA

Background： Integration of behavioral observations with traditional selection schemes may lead to enhanced animal well-being and more profitable forage-based cattle production ***-influenced（Br;n = 64） and Gelbvieh × Angus（GA;n = 64） heifers consumed either toxic endophyte-infected tall fescue（E＋） or one of two nontoxic endophyte-infected tall fescue（NT） cultivars during two *** were weighed at midpoint and termination of *** behavior（grazing,resting in the shade,lying,or standing without grazing） was recorded（n = 13 visual observations per yr in June and July） for each *** yr 2,exit velocity（EV） and serum prolactin（PrL） were ***： Grazing behavior was influenced（P 0.05） by an interaction between fescue cultivar and breed *** × Angus heifers assigned to E＋ pastures had the lowest percentage of animals grazing and the largest percentage of animals resting in the ***-influenced heifers had faster EV（P 0.001） than GA heifers（0.52 vs.0.74 ± 0.04 s/m,respectively）.Body weight（BW） was affected（P 0.01） by an interaction of tall fescue cultivar and d,and an interaction of tall fescue cultivar and breed *** grazing NT pastures were heavier（P 0.01） than heifers grazing E＋ pastures at midpoint and *** × Angus heifers grazing NT pastures were heavier（P 0.01） than GA and Br heifers grazing E＋ and Br heifers grazing NT *** interaction of forage cultivar and breed type occurred on serum PrL（P 0.01）.Conclusion： Collectively fescue cultivar,EV,and concentrations of serum PrL were associated with grazing *** grazing NT pastures were observed to be grazing more than heifers assigned to E＋ pastures,regardless of breed type,which may have contributed to changes in BW and average daily gain（ADG） in *** of behavioral observations along with traditional selection schemes may lead to enhanced animal well-being and more profitable forage-based cattle prod

关键词： Cattle Endophyte-infected tall fescue Grazing behavior Prolactin Temperament

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relationship of late-season ear leaf nitrogen with early- to mid-season plant height of corn

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Agricultural Sciences 2012年第2期3卷 306-316页

作者： Xinhua Yin M. angela McClure robert M. Hayes Department of Plant Sciences The University of Tennessee Jackson USA West Tennessee research and Education Center The University of Tennessee Jackson USA

Nitrogen concentration in the ear leaf is a good indicator of corn (Zea mays L.) N nutrition status during late growing season. This study was done to examine the relationship of late-season ear leaf N concentration with early- to mid- season plant height of corn at Milan, TN from 2008 to 2010 using linear, quadratic, square root, logarithmic, and exponential models. Six N rate treatments (0, 62, 123, 185, 247, and 308 kg·N·ha-1) repeated four times were implemented each year in a randomized complete block design under four major cropping systems: corn after corn, corn after soybean [Glycine max (L.) Merr.], corn after cotton [Gossypium hirsutum (L.)], and irrigated corn after soybean. The relationship of ear leaf N concentration determined at the blister growth stage (r2) with plant height measured at the 6-leaf (V6), 10-leaf (V10), and 12-leaf (V12) growth stages was statistically significant and positive in non-irrigated corn under normal weather conditions. However, the strength of this relationship was weak to moderate with the determination coefficient (r2) values ranging from 0.21 to 0.51. This relationship was generally improved as the growing season progressed from V6 to V12. Irrigation and abnormal weather seemed to have adverse effects on this relationship. The five regression models performed similarly in the evaluation of this relationship regardless of growth stage, year, and cropping system. Our results suggest that unlike the relationship of corn yield at harvest with plant height measured during early- to mid-season or the relationship of leaf N concentration with plant height when both are measured simultaneously during early- to mid-season, the relationship of late-season ear leaf N concentration with early- to mid-season plant height may not be strong enough to be used to develop algorithms for variable-rate N applications on corn within a field no matter which regression model is used to describe this relationship.

关键词： Corn Ear Leaf N Plant Height relationship Models Cropping Systems

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