W. K. Coblentz

Carcass and beef color characteristics of three biological types of cattle grazing cool-season forages supplemented with soyhulls

Soyhull supplementation to divergent biological types of cattle on forage-based systems was studied to determine the impact on carcass and color characteristics. Weaned calves (n=107) biologically classified as large-, medium-, or small-framed and intermediate rate of maturing were allocated to three cool-season grazing systems consisting of either orchardgrass pasture or fescue pasture, each with soyhull supplementation, or fescue pasture with no supplementation as a control. Supplementing cattle with soyhulls allowed for heavier (P<0.05) live and carcass weights, larger (P<0.05) longissimus muscle area, increased (P<0.05) backfat, kidney, pelvic and heart fat (KPH), and yield grades, and improved (P<0.05) marbling scores and quality grades. Utilizing cattle biologically classified as large- or medium-framed allowed for heavier (P<0.05) carcass weights without reducing (P<0.05) marbling scores or quality grades when compared to small-framed cattle. Instrumental color analysis of lean and adipose tissue revealed improved (P<0.05) lightness (L (∗)) in lean color for supplemented carcasses as compared to the control. There were no differences (P<0.05) between dietary treatments for L (∗), a (∗) or b (∗) values of adipose tissue. These results indicate that supplementing forage-grazing cattle with soyhulls can improve carcass merit, and utilizing large- or medium-framed cattle can allow for increased carcass weights without decreasing carcass quality.

Effects of Nitrogen Fertilization on Phosphorus Uptake in Bermudagrass Forage Grown on High Soil-Test Phosphorus Sites

Abstract Common bermudagrass [Cynodon dactylon (L.) Pers.] was harvested from two producer sites (Latta and Stephens) with high soil-test P (286 and 153 ppm, respectively) to assess the effects of N fertilization on P uptake and potential removal in hay or silage. Ammonium nitrate was applied in split applications each year at rates totaling 0, 56, 112, 168, 224, 280, or 336 kg/ha of actual N. At the Stephens site in Yr 1, cumulative DM yield increased linearly (P 0.10) between concentration of P and N fertilization rate (overall mean = 0.40%), but concentrations of P declined in linear (P

Changes in nutritive value of tall fescue hay as affected by natural rainfall and moisture concentration at baling

Relatively little is known about the combined effects of rain damage and spontaneous heating on the storage characteristics and nutritive value of tall fescue (Festuca arundinacea Schreb.) hay. Objectives were to assess effects of these variables in five management situations. ‘Kentucky 31’ tall fescue infested with the fungal endophyte (Neotyphodium coenophialum [Morgan-Jones & Glenn, Bacon, and Hamlin comb. nov.]) was packaged in conventional rectangular bales at 99 g/kg (low, L), 164 g/kg (ideal, I), and 225 g/kg (high, H) of moisture prior to rainfall, and at 246 g/kg of moisture after a 23 mm rainfall event (H–R) and at 93 g/kg of moisture after a total accumulation of 72 mm of rain (L–R). Concentrations of neutral-detergent fiber (NDF), acid-detergent fiber (ADF), and lignin immediately after baling increased (P≤0.017) with rain damage, but concentrations of total N and fiber-associated N components were little affected. Immediately after baling, the in situ dry matter (DM) disappearance for L–R hay was 32–44 g/kg lower (P=0.0001) than observed for hays baled without rain damage. After a 40–45-day storage period, L and I hays had a 31–36 g/kg advantage for in situ DM disappearance over hays damaged by spontaneous heating (H), rainfall (L–R), or both (H–R). Generally, the effects of a single 23 mm rainfall event on the nutritive value of tall fescue hay was relatively small, but damage increased substantially with multiple rainfall events.

Estimating Degradable Intake Protein in Warm- and Cool-Season Forages Grown on Producer Farms in Northern Arkansas

Two case studies were conducted on producer farms in northwest Arkansas to assess degradable intake protein (DIP) and undegradable intake protein (UIP) in forages grown throughout the region. In Case Study 1, DIP was greater (P 0.05) in warm-season pastures when DIP was expressed as a percentage of CP. In Case Study 2, N fertilization in April and July at two producer sites (Latta and Stephens) increased concentrations of CP for subsequent harvests in primarily linear (P 0.05) for a mid-summer (July 7) harvest that received no fertilization. In harvests immediately following fertilization, DIP increased; the linear term was significant (P≤0.004) in each case, but it was coupled with quadratic or cubic effects in some harvests. For the second harvest at each site, DIP was not affected (P>0.05) by residual effects of the initial application of N fertilizer in April. The size of the UIP pool also increased linearly (P≤0.002) immediately following N fertilization in three of four harvests, but the magnitude of these responses was small compared with those observed for DIP.

Review: Quality Characteristics of Eastern Gamagrass Forages

Abstract Eastern gamagrass [Tripsacum dactyloides L.] is a native, warm-season, perennial, bunch-type grass adapted generally to moist sites throughout much of the eastern United States. Nitrogen concentrations of eastern gamagrass will normally exceed 20 g/kg at growth stages (boot and anthesis) that produce reasonable yields. With moderate N fertilization, concentrations of N approaching 32 g/kg are realistic in whole-plant tissue harvested at boot stage in the upper Midwest. Recent studies suggest that high proportions (>50%) of this N are insoluble in neutral detergent (NDIN), thereby implying association with the cell wall. In situ studies in Kansas have shown that the potential extent of ruminal N degradation for gamagrass harvested at boot stage is comparable with that of high quality legumes, but degradation occurs at slower rates; generally, similar trends have been observed for in situ disappearance of DM and fibrous components. Increasing plant maturity appears to limit extent primarily, but not the rate, of degradation for these plant components. Concentrations of NDF are generally high (>600 g/kg), even at immature growth stages; this observation is consistent with findings for other warm-season grasses. In studies conducted throughout the mid South, researchers report that ADG ranged between 0.5 and 1.0 kg/d for steers continuously grazing eastern gamagrass pastures. Daily gains are likely to be reduced as days on pasture increase. Mounting evidence suggests that gamagrass grown in the Midwest demonstrates better quality characteristics than that grown in the Southeast.

Comparison of bloat potential between a variety of soft-red versus a variety of hard-red winter wheat forage

Some aspects of wheat pasture bloat have been researched extensively, but few studies have evaluated the effect of wheat type or variety on bloat. Eight Gelbvieh x Angus ruminally cannulated heifers (515 +/- 49 kg of BW) and 48 Angus heifers (238 +/- 12 kg of BW) grazed 1-ha pastures of hard-red or soft-red winter wheat (Triticum aestivum L.) to evaluate the effect of wheat variety on bloat potential. In Exp. 1, cattle grazed from November 11 to 22 and from November 26 to December 7, 2006, in a crossover design. In Exp. 2, cattle were shrunk for 20 h and then grazed from December 19 to 20, 2006, and from January 19 to 20, 2007. In both experiments, bloat was scored at 1000 and 1600 h daily. Rumen samples were collected at 0600, 1200, and 1800 h during each of the last 2 d of each period in Exp. 1 and during both days of each period of Exp. 2. Rumen samples were evaluated for pH, foam production and strength, and viscosity. In Exp. 1, cannulated heifers grazing soft-red had a greater (P < 0.01) percentage of observed bloat (21.9 vs. 5.6%) than those grazing hard-red winter wheat, but bloat incidence was low (2.1%) for the stocker cattle, with no difference between hard-red and soft-red winter wheat (P = 0.52). Viscosity of the rumen fluid was affected (P = 0.03) by the wheat variety x time interaction, with soft-red at 1200 and 1800 h being more viscous than soft-red at 0600 h and hard-red at all times. Foam strength, as determined by bubbling CO(2) gas through rumen fluid, had a wheat variety x time interaction (P = 0.02) with both wheat varieties similar at 0600 h but soft-red having greater foam strength at 1200 and 1800 h. In Exp. 2, no bloat was observed, and no differences between wheat varieties were observed for any of the rumen foam measures. Therefore, for these 2 varieties, the soft-red winter wheat had a greater bloat potential than the hard-red winter wheat based on results from the cannulated heifers, but no differences were observed in the frequency of bloat in stocker cattle. In this study, shrinking of cattle before grazing wheat pasture did not induce bloat.

Mineral Content of Forages Grown on Poultry Litter-Amended Soils1

Abstract Large quantities of poultry litter are applied each year to pastures in Arkansas and Oklahoma. Our objective was to monitor mineral concentrations in forages grown on poultry litter-amended soils and compare them with mineral requirements for gestating and early lactating beef cows. A total of 65 forage samples were gathered from four farms in northwest Arkansas and northeast Oklahoma from April 2000 to March 2002. Mean forage mineral concentrations were compared with beef cattle requirements using a two-tailed t test. Two-year average forage Ca, P, K, S, and Fe concentrations from each farm exceeded (P 0.05) from gestation and lactation requirements. On individual sampling dates, concentrations of Ca, P, K, and Zn rarely fell below lactation requirements. Mean forage Mg concentrations from one farm exceeded (P 0.05) lactation requirements. Mean tetany ratios from all farms were below (P 0.05) from the requirements on three farms. Forages from pastures fertilized with broiler litter may meet most but not all mineral requirements of beef cattle, and supplementation of specific minerals, particularly Mg and Cu, may be necessary.

Evaluation of Soft Red Winter Wheat Forage Yield, Nutritive Value and Tetany Hazard as Influenced by Sampling Date and Nitrogen Fertilization

Abstract Bailey, C.R., Daniels, L.B., Coblentz, W.K., Kegley, E.B., McBeth, L.J., Turner, J.E., Wistuba, T.J. and Rosenkrans Jr., C.F. 2007. Evaluation of soft red winter wheat forage yield, nutritive value and tetany hazard as influenced by sampling date and nitrogen fertilization. J. Appl. Anim. Res., 32: 1–6. A study was conducted from December through March using a completely randomized design to evaluate yield, nutritive value and tetany hazard of soft red winter wheat (Triticum aestivum L.) forage as influenced by nitrogen (N) fertilization rate and date of sampling. Dry matter (DM) yield, forage DM, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), in vitro, dry matter disappearance (IVDMD), organic matter (OM), calcium (Ca), magnesium (Mg) and potassium (K) were evaluated. Nitrogen fertilization had no effect (P>0.05) on forage yield, OM, ADF, NDF, IVDMD, Ca or Mg. Forage DM (P<0.01) decreased while CP (P<0.01) andK(P<0.05) increased linearly with increasing levels of N fertilization. Date of sampling exhibited linear, quadratic, cubic and quartic effects (P≤0.01) on concentrations of forage CP, DM, PVDMD, ADF, NDF and K. With respect to sampling date, linear (P<0.01) and quadratic (P=0.01) effects were observed for DM yield, but only linear effects were noted for OM (P<0.01). Calcium responded to sampling date with linear and cubic (P<0.01) patterns, while Mg exhibited linear (P<0.01), quadratic (P<0.01), and cubic (P=0.02) effects. No N × sampling date interactions were observed. Increasing levels of N enhanced concentrations of CP and decreased DM content, but had no effect on yield or other forage quality parameters. However, sampling date affected forage quality by decreasing concentrations of CP and IVDMD, while increasing concentrations of ADF and NDF.

Growth, Luteal Activity, and Pregnancy Rates of Three Breed Types of Dairy Heifers in a Forage-Based Development Program

Growth, luteal activity, and pregnancy rates were evaluated in 89 dairy heifers raised as contemporaries. Breed types were Holstein (H, n = 35), Jersey x H (JH, n = 30), and Brown Swiss x H (BSH, n = 24); they ranged in age from 129 to 205 d at the beginning of the trial. Heifers grazed pasture and received grain supplementation to ensure 0.9 kg of daily BW gain. Hip height, chest depth, and BW were obtained monthly; BCS was recorded at ca. 14 mo of age. At ca. 12 mo of age, two blood samples for each heifer were collected (10 d apart) by jugular vein puncture for progesterone assay. Heifers were considered cycling if progesterone concentrations were > 1 ng/ mL in either of the two serum samples. Heifers were bred artificially (AI) on a synchronized estrus starting at 14 mo of age, and pregnancy status was determined ultrasonically 60 d after breeding. The BSH and H had similar (P>0.05) weights and hip heights; whereas JH were lighter and shorter (P 0.05) occurred for depth of chest and mean BCS. Estrus occurrence by 12 mo of age was greater (P<0.05) for JH (90%) than for BSH (75%) and lowest (P<0.05) for H (47%). Pregnancy rates did not differ (BSH = 96%, JH = 87%, H = 77%). These data suggest that genetic effects of crossbreeding influence early growth and cyclicity at 12 mo of age for replacement dairy heifers. Forage-based development of dairy heifers may be a suitable option to concentrate feeding for dairy producers in Arkansas and the Southern Region.