Effects of supplemental safflower and vitamin E during late gestation on lamb growth, serum metabolites, and thermogenesis

Twin-bearing Targhee ewes (Exp. 1, 1 yr, n = 42) and 1,182 single- and twin-bearing whiteface range ewes (Exp. 2, n = 8 experimental units over 2 yr) were used in a 2 x 2 factorial arrangement of treatments to determine the effect of supplemental energy source and level of vitamin E supplement on lamb serum metabolites and thermogenesis (Exp. 1) and on lamb growth (Exp. 2). During late gestation, ewes were individually fed (Exp. 1) or group-fed (Exp. 2) a daily supplement. Supplements were 226 g/ewe of daily safflower seed (DM basis; SS) with either 350 IU/ewe daily (VE) or no added supplemental (VC) vitamin E; or 340 g/ewe daily of a barley-based grain supplement (DM basis; GC) and either VE or VC. One hour postpartum in Exp. 1, twin-born lambs were placed in a 0 degrees C dry cold chamber for 30 min. Lamb rectal temperature was recorded every 60 s and blood samples were taken immediately before and after cold exposure. In Exp. 2, lambs were weighed at birth, at turnout from confinement to spring range (32 d of age +/- 7; turnout), and at weaning (120 d of age +/- 7). Ewes were weighed at turnout and weaning. In Exp. 1, a level of vitamin E x energy source interaction was detected (P < 0.10) for body temperature and change in NEFA and glucose concentrations. Lambs from SSVC ewes had the lowest (P = 0.01) body temperature and had decreased (P = 0.08) NEFA concentration. The SS lambs tended to have decreased (P < 0.11) concentrations of blood urea N (BUN) and thyroxine at 0 min than did lambs born to GC ewes. After 30 min of cold exposure, SS lambs had increased and GC lambs had decreased BUN, triiodothyronine, and triiodothyronine:thyroxine concentrations (P < 0.10). In Exp. 2, kilograms of lamb per ewe at turnout and weaning and lamb survival at weaning were greater (P < 0.07) for GC than SS lambs. Based on the decreased body temperature in SSVC lambs at birth, the greater change in BUN during the cold exposure for SS than GC lambs, and the decreased survival rate for SS than GC lambs, SSVC-supplemented ewes appeared to give birth to lambs with an apparently decreased energetic capacity. This may compromise the ability of the newborn lamb to adapt to extreme environmental conditions.     

Dormant Season Grazing: Effect of Supplementation Strategies on Heifer Resource Utilization and Vegetation Use

Grazing dormant forage under low-input heifer development strategies typically exposes cattle to low-quality forage. Protein supplementation while grazing dormant range can enhance heifer growth and reproductive performance. We examined resource utilization of heifers and the effects of dormant season grazing on residual vegetation characteristics under two supplementation management strategies. Approximately 100 weaned composite heifer calves were randomly selected and placed into one of two supplementation treatments in each of 2 yr, one receiving a free access 62% crude protein self-fed concentrate and the other receiving a daily hand-fed 20% crude protein cake. Grazing occurred from December (2015 and 2016) through March (2016 and 2017). Thirty transects were randomly located within each pasture for measuring vegetation quality and structure before and after grazing. Daily space use and behavior was evaluated for 21 individuals within each treatment using global positioning system (GPS) collars and resource utilization functions. Heifers supplemented with concentrated protein spent more time grazing per day than heifers supplemented with cake (6.92 ± 0.18, 6.24 ± 0.17 h). Relative use by heifers in the cake treatment was negatively related to horizontal distance from the supplement delivery site early to midwinter ($\stackrel{?}{\overline{\beta }}$ = ? 0.41 ± 0.16, ? 0.53 ± 0.17). Both treatments selected grazing locations relative to standing biomass of perennial grasses ($\stackrel{?}{\overline{\beta }}$ = 0.0005 ± 0.00004) and crude protein ($\stackrel{?}{\overline{\beta }}$ = 0.12 ± 0.007). However, resource selection was highly variable among individuals for both supplementation treatments. We found no treatment effects on pre-post grazing differences in residual cover of litter, grass, forbs and shrubs (P > 0.24). However, the time period when grazing occurred had an effect on residual vegetation conditions (P < 0.01). Our results indicate high levels of variability in grazing site selection by heifers, suggesting future research should incorporate individual animal measurements in an attempt to account for individual animal variability.     

Feeding and watering behavior of healthy and morbid steers in a commercial feedlot

Our objective was to determine whether there were differences in feeding and watering behavior of newly received healthy and morbid feedlot steers. Two separate 32-d feeding trials were conducted in Wellton, Arizona, in July and November 1996. Radio frequency technology was used to record individual animal behaviors from 108 (average weight 139 kg) and 143 (average weight 160 kg) steers in each respective trial. Steers that were subsequently identified as morbid were present at the feed bunk in greater percentages than reported in previous studies. In Trial 1, healthy steers spent more (P < .001) time at the feed bunk and had more (P < .009) feeding bouts than morbid steers. In Trial 2, healthy steers did not spend more time at the feed bunk, but they had more (P < .02) daily feeding bouts than morbid steers. There were no differences in daily time spent at the water trough by healthy or morbid steers in either trial. The greatest proportion of feeding and watering behavior occurred during the daylight hours in response to feed delivery. The pattern of time spent at the feed bunk throughout the 32-d feeding period was similar for healthy and subsequently morbid steers, but healthy steers had more feeding bouts per day.     

Triblock copolymer syntheses of mesoporous silica with periodic 50 to 300 angstrom pores

Use of amphiphilic triblock copolymers to direct the organization of polymerizing silica species has resulted in the preparation of well-ordered hexagonal mesoporous silica structures (SBA-15) with uniform pore sizes up to approximately 300 angstroms. The SBA-15 materials are synthesized in acidic media to produce highly ordered, two-dimensional hexagonal (space group p6mm) silica-block copolymer mesophases. Calcination at 500 degrees C gives porous structures with unusually large interlattice d spacings of 74.5 to 320 angstroms between the (100) planes, pore sizes from 46 to 300 angstroms, pore volume fractions up to 0.85, and silica wall thicknesses of 31 to 64 angstroms. SBA-15 can be readily prepared over a wide range of uniform pore sizes and pore wall thicknesses at low temperature (35 degrees to 80 degrees C), using a variety of poly(alkylene oxide) triblock copolymers and by the addition of cosolvent organic molecules. The block copolymer species can be recovered for reuse by solvent extraction with ethanol or removed by heating at 140 degrees C for 3 hours, in both cases, yielding a product that is thermally stable in boiling water.     

Optimising tobacco market locations: Part II—Heuristic models

Heuristic programming models of the flue-cured tobacco marketing system in the southeastern United States were developed to solve capacitated location-allocation problems with trillions of feasible solutions (large numbers of markets in the systems). For several small problems, the heuristic models' results were cmmpared to results generated by the theoretical mixed integer model. The results indicated that the heuristic algorithm rapidly determined optimum or near optimum solutions in all comparisons. The heuristic model was then utilised to solve capacitated market location-allocation problems for the flue-cured tobacco industry by parametrically varying the desired number of markets in the system.     

Liquid supplement and forage intake by range beef cows

One hundred eighty crossbred cows were assigned to one of six native range pastures during two winters to evaluate forage and supplement intake as affected by liquid supplement (yr 1: 50% crude protein, 84% from urea; yr 2: 57% crude protein, 91% from urea) delivery method and cow age (2, 3, 4, 5, or 6 yr). Treatments were: 1) no supplement (Control); 2) a lick-wheel feeder containing liquid supplement (ADLIB); and 3) a computer-controlled lick-wheel feeder that dispensed 0.9 kg x cow(-1) x d(-1) of liquid supplement (average 0.5 kg of dry matter x cow(-1) x d(-1); Restricted). Each treatment was applied to two pastures. Forage digestibility was increased (P = 0.03) by supplementation. Supplemented cows lost less (P = 0.05) body condition than unsupplemented cows (average -0.3 vs -0.6). Blood urea nitrogen (BUN) was highest (P = 0.001) for ADLIB (8.7 mg/dL), intermediate for Restricted (6.2 mg/dL), and lowest for Control (2.3 mg/dL). Forage DMI was 31% higher (P = 0.01) in 1995 than in 1996, and was increased (P = 0.02) by supplementation both years. Cows supplemented with ADLIB consumed 23% more forage dry matter than Control cows, whereas Restricted cows consumed 21% more dry matter than ADLIB cows. Supplement intake by cows on ADLIB was greater (P = 0.001) than by cows on Restricted in both years. Supplement intake was lowest (P = 0.002) by 2-yr-old cows, intermediate by 3-yr-olds, and greatest by 4-, 5-, and 6-yr-old cows. Variation in supplement intake by individual cows was higher (P = 0.09) for cows in the Restricted treatment (coefficient of variation [CV] = 117%) than those on ADLIB (CV = 68%) during the first year, but did not differ between supplement treatments (average CV = 62%) in the second year. The proportions of cows consuming less than 0.3 kg/d of supplement dry matter intake (DMI) and consuming less than the target amount of supplement (0.5 kg DMI) were less (P = 0.001) for ADLIB than for Restricted during both years. ADLIB cows spent more (P = 0.001) time at the supplement feeder and had more (P < 0.002) supplement feeding bouts than Restricted cows during both years. During the first year, 2- and 3-yr-old cows spent less (P < 0.01) time at the feeder and had fewer feeding bouts per day than 6-yr-old cows. Age had no effect (P > 0.24) on feeding behavior during the second year. Supplementation of beef cows grazing winter range with 50 to 57% crude protein liquid supplement increased forage digestibility and intake. Restricting supplement access increased forage consumption and variability of supplement intake.     

Aspen Recovery Since Wolf Reintroduction on the Northern Yellowstone Winter Range

Quaking aspen (Populus tremuloides Michx.) recruitment and overstory stem densities were sampled in 315 clones in 1991 and 2006 on 560 km² of the Northern Yellowstone Winter Range (NYWR). A primary objective was to observe if aspen status had improved from 1991 to 2006: evidence of a wolf (Canis lupus) caused trophic cascade. Recruitment stems (height > 2 m and diameter at breast height < 5 cm) represent recent growth of aspen sprouts above elk (Cervus elaphus) browsing height, whereas overstory stems (all stems > 2 m) represent the cohort of stems, which will insure the sustainability of the clone. Overstory stem densities declined by 12% (P = 0.04) on the landscape scale when compared with paired t-tests. Overstory stems declined in 58% of individual clones and in 63% of the 24 drainages of the study area. The second objective was to determine which factors influenced changes in aspen density. Winter ungulate browsing (P = 0.0001), conifer establishment (P = 0.0001), and cattle (Bos spp.) grazing (P = 0.016) contributed to the decline in overstory stem densities when analyzed using a mixed effects model of log transformed medians. Eighty percent of the clones were classified as having medium to high browsing levels in 1991, whereas 65% of the clones received a similar rating in 2006, possibly due to the reduced NYWR elk population. Aspen recruitment has increased in some 2–10 km² areas, but not consistently. Our study found that a trophic cascade of wolves, elk, and aspen, resulting in a landscape-level recovery of aspen, is not occurring at this time.