Technical note: evaluation of acid detergent lignin, alkaline peroxide lignin, acid insoluble ash, and indigestible acid detergent fiber as internal markers for prediction of alfalfa, bromegrass, and prairie hay digestibility by beef steers.

Six steers (BW = 436 +/- 15 kg) were assigned randomly to alfalfa, bromegrass, or prairie hay diets in a replicated 3 x 3 Latin square design to evaluate the efficacy of different internal markers for estimating OM digestibility (OMD). Internal markers used to estimate OMD included ADL, alkaline peroxide lignin (APL), AIA, and indigestible ADF (IADF), which consisted of a 144-h in vitro incubation (IADFWOUT), indigestible ADF with acid/pepsin pretreatment of feed and orts samples (IADFFEED), or acid/pepsin pretreatment of feed, orts, and fecal samples (IADFALL). Marker-derived estimates of OMD were compared with OMD measured by total fecal collection (TFC). For the alfalfa diet, all marker estimates differed (P less than .05) from the TFC measurement; however, lignin-based procedures (ADL and APL) and IADF with acid/pepsin pretreatment (IADFFEED, IADFALL) were numerically closest to TFC values. Estimates of bromegrass and prairie hay OMD by ADL, APL, and AIA ratio were not different (P greater than .05) from TFC measurement, although AIA seemed to provide the most accurate estimate for prairie hay. All indigestible ADF procedures yielded estimates of forage OMD that differed (P less than .05) from TFC for all forages; acid/pepsin pretreatment of samples (IADFFEED and IADFALL) improved accuracy of the OMD estimates in all forages. Likewise, recovery of indigestible ADF was consistently least among the markers evaluated. These results indicate that APL ratio performed similarly to ADL ratio in estimating forage OMD, that AIA estimated grass OMD very accurately, and that estimation of OMD by indigestible ADF ratio was improved when the procedure was accompanied by an acid/pepsin pretreatment of samples.     

Ruminal and host adaptations to changes in frequency of protein supplementation

The effect of altering supplementation frequency on host N balance and key N transactions in the ruminal ecosystem were monitored. Four ruminally fistulated beef steers (BW = 513 kg; SEM = 6.5) were used in a 2 x 2 crossover design with two periods and two supplementation frequency treatments. Supplementation frequencies were 2 and 7 d/wk. Steers were fed tallgrass prairie hay (73.1% NDF, 5.3% CP) ad libitum. Supplement (42% CP; DM basis) was fed at 0.36% BW/d to steers supplemented 7 d/wk. Steers supplemented 2 d/wk received the same amount of supplement per week, but it was equally split among the two supplementation events. Steers supplemented 7 d/wk had higher forage (P < 0.02) and total digestible OM intake (P < 0.06), total N intake, fecal N excretion, and N retention. Although both supplementation frequencies were characterized by positive N balance, the decrease in N retention in the steers supplemented 2 d/wk was due to higher (P < 0.01) urinary N loss. Ruminal fluid was sampled at 0, 2, 4, 6, 12, 24, 48, and 72 h after supplementation beginning on a day when both treatments were supplemented. Frequency x hour interactions (P < 0.02) were observed for ruminal N metabolism criteria. Counts of peptide- and AA-fermenting bacteria peaked at 2 h and returned to nadir by 12 h for steers supplemented 7 d/wk. Steers supplemented 2 d/wk peaked at 6 h with a greater population and returned to nadir at 48 h. Ruminal ammonia concentrations followed a similar trend. Specific activity of ammonia production was lower (P < or = 0.05) immediately after supplementation for steers supplemented 2 d/wk, but by 12 h was the same as for 7 d/wk steers. Ruminal peptides and free AA peaked at 2 h for steers supplemented 2 d/wk and were generally higher (P < or = 0.05) during the first 6 h compared with steers supplemented 7 d/wk. Total VFA concentration was not different (P = 0.35) due to supplementation frequency. Frequency x hour interactions (P < 0.01) were observed for all molar proportions of VFA. The molar proportion of acetate and acetate:propionate ratio were lower (P < 0.01) and the molar proportions of propionate and butyrate were higher for steers supplemented 2 d/wk from 4 h to 24 h. In conclusion, forage use and N balance improved with supplementation 7 d/wk, but supplementation 2 d/wk was associated with some desirable shifts in select ruminal events that may contribute to moderating potential negative impacts of supplementing infrequently.     

Compatibility between livestock databases used for quantitative biosecurity response in New Zealand

AIM: To characterise New Zealand's livestock biosecurity databases, and investigate their compatibility and capacity to provide a single integrated data source for quantitative outbreak analysis.

METHODS: Contemporary snapshots of the data in three national livestock biosecurity databases, AgriBase, FarmsOnLine (FOL) and the National Animal Identification and Tracing Scheme (NAIT), were obtained on 16 September, 1 September and 30 April 2014, respectively, and loaded into a relational database. A frequency table of animal numbers per farm was calculated for the AgriBase and FOL datasets. A two dimensional kernel density estimate was calculated for farms reporting the presence of cattle, pigs, deer, and small ruminants in each database and the ratio of farm densities for AgriBase versus FOL calculated. The extent to which records in the three databases could be matched and linked was quantified, and the level of agreement amongst them for the presence of different species on properties assessed using Cohen's kappa statistic.

RESULTS: AgriBase contained fewer records than FOL, but recorded animal numbers present on each farm, whereas FOL contained more records, but captured only presence/absence of animals. The ratio of farm densities in AgriBase relative to FOL for pigs and deer was reasonably homogeneous across New Zealand, with AgriBase having a farm density approximately 80% of FOL. For cattle and small ruminants, there was considerable heterogeneity, with AgriBase showing a density of cattle farms in the Central Otago region that was 20% of FOL, and a density of small ruminant farms in the central West Coast area that was twice that of FOL. Only 37% of records in FOL could be linked to AgriBase, but the level of agreement for the presence of different species between these databases was substantial (kappa >0.6). Both NAIT and FOL shared common farm identifiers which could be used to georeference animal movements, and there was a fair to substantial agreement (kappa 0.32–0.69) between these databases for the presence of cattle and deer on properties.

CONCLUSIONS: The three databases broadly agreed with each other, but important differences existed in both species composition and spatial coverage which raises concern over their accuracy. Importantly, they cannot be reliably linked together to provide a single picture of New Zealand's livestock industry, limiting the ability to use advanced quantitative techniques to provide effective decision support during disease outbreaks. We recommend that a single integrated database be developed, with alignment of resources and legislation for its upkeep.     

Kepler-36: a pair of planets with neighboring orbits and dissimilar densities

In the solar system, the planets' compositions vary with orbital distance, with rocky planets in close orbits and lower-density gas giants in wider orbits. The detection of close-in giant planets around other stars was the first clue that this pattern is not universal and that planets' orbits can change substantially after their formation. Here, we report another violation of the orbit-composition pattern: two planets orbiting the same star with orbital distances differing by only 10% and densities differing by a factor of 8. One planet is likely a rocky "super-Earth," whereas the other is more akin to Neptune. These planets are 20 times more closely spaced and have a larger density contrast than any adjacent pair of planets in the solar system.     

Effects of hydrated sodium calcium aluminosilicate on fescue toxicosis and mineral absorption.

The possibility of supplementing livestock diets with an aluminosilicate to protect them from fescue toxicosis was investigated. An in vitro study showed that hydrated sodium calcium aluminosilicate (HSCAS) removed greater than 90% of the ergotamine from aqueous solutions at pH 7.8 or lower, indicating a high affinity of ergotamine for HSCAS in vitro. Rats fed diets containing tall fescue seed infested (E+) with the endophytic fungus Acremonium coenophialum had lower (P less than .05) feed intakes and weight gains than did rats fed diets containing uninfested (E-) tall fescue seed. When feed intake by rats fed the E- seed diet was limited to that of rats fed the E+ seed diet, weight gains did not differ, but testes weights and serum prolactin (PRL) concentrations were lower (P less than .05 and .10, respectively) in rats receiving E+ seed. Supplementing E+ seed diets with HSCAS did not eliminate effects of E+ seed on intake, PRL, or testes weights. Sheep fed E+ tall fescue hay had higher (P less than .05) rectal temperatures than did sheep fed an equal amount of E- tall fescue hay, but OM and N digestion coefficients did not differ between the two hays. Supplementing E+ hay diets with HSCAS did not eliminate the effect of E+ hay on rectal temperatures. Addition of 2% HSCAS to tall fescue hay diets did not affect apparent absorption by sheep of OM, N, Ca, P, Na, K, or Cu, but it reduced (P less than .05) the apparent absorption of Mg, Mn, and Zn.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fertility of Angus cross beef heifers after GnRH treatment on day 23 and timing of insemination in 14‐day CIDR protocol

This study compared artificial insemination pregnancy rate (AI‐PR) between 14‐day CIDR‐GnRH‐PGF2α‐GnRH and CIDR‐PGF2α‐GnRH synchronization protocol with two fixed AI times (56 or 72 hr after PGF2α). On day 0, heifers (n = 1311) from nine locations assigned body condition score (BCS: 1, emaciated; 9, obese), reproductive tract score (RTS: 1, immature, acyclic; 5, mature, cyclic) and temperament score (0, calm; and 1, excited) and fitted with a controlled internal drug release (CIDR, 1.38 g of progesterone) insert for 14 days. Within herd, heifers were randomly assigned either to no‐GnRH group (n = 635) or to GnRH group (n = 676), and heifers in GnRH group received 100 μg of GnRH (gonadorelin hydrochloride, IM) on day 23. All heifers received 25 mg of PGF2α (dinoprost, IM) on day 30 and oestrous detection aids at the same time. Heifers were observed for oestrus thrice daily until AI. Within GnRH groups, heifers were randomly assigned to either AI‐56 or AI‐72 groups. Heifers in AI‐56 group (n = 667) were inseminated at 56 hr (day 32 PM), and heifers in AI‐72 group (n = 644) were inseminated at 72 hr (day 33 AM) after PGF2α administration. All heifers were given 100 μg of GnRH concurrently at the time AI. Controlling for BCS (p < .05), RTS (p < .05), oestrous expression (p < .001), temperament (p < .001) and GnRH treatment by time of insemination (p < .001), the AI‐PR differed between GnRH treatment [GnRH (Yes – 60.9% (412/676) vs. No – 55.1% (350/635); p < .05)] and insemination time [AI‐56 – 54.6% (364/667) vs. AI‐72 – 61.8% (398/644); (p < .01)] groups. The GnRH treatment by AI time interaction influenced AI‐PR (GnRH56 – 61.0% (208/341); GnRH72 – 60.9% (204/335); No‐GnRH56 – 47.9% (156/326); No‐GnRH72 – 62.8% (194/309); p < .001). In conclusion, 14‐day CIDR synchronization protocol for FTAI required inclusion of GnRH on day 23 if inseminations were to be performed at 56 hr after PGF2α in order to achieve greater AI‐PR.     

Soil microbial biomass and enzyme activity in subarctic agricultural and forest soils

Summary Microbial biomass, activities of dehydrogenase, phosphatase, and urease, and numbers of ammonium oxidizers were determined at monthly intervals on soil samples obtained from an on-going tillage residue-management study during the summers of 1985 and 1986. The site was cleared of black spruce (Picea mariana, Mill.) in 1979 and has been planted to spring barley (Hordeum vulgare) since 1982. Tillage treatments were no-tillage or disked twice, and residuemanagement treatments were removal of stubble and loose straw or leaving all straw on the plots. Microbial biomass and enzyme activities were moderate to high in the Ap horizon but very low in the B horizon. There was no difference in any parameter measured due to tillage or residue management. In 1986, comparisons were made between the Ap horizon and the agricultural soil and the A horizon of the soil beneath an adjacent black-spruce forest. Total microbial biomass and enzyme activities were generally greater in the forest soil than in the agricultural soil. However, specific activity of the biomass was generally greater in the agricultural soil. Soil microbial biomass and urease activities of both agricultural and forest soils were similar to those reported for warmer climates, but dehydrogenase activity was higher and phosphatase was lower.     

Scavenging Processes and Export Fluxes Close to a Retreating Seasonal Ice Margin (Ross Sea, Antarctica)

The distribution of dissolved and particulate 234Th in the upper 200 m of the water column was obtained for three stations in the Ross Sea off Victoria Land and Terra Nova Bay. At site 24a, close to the retreating ice margin, all the sampled depths showed deficiencies in 234Th relative to the equilibrium with 238U. These are related to uptake of 234Th onto sinking particles. Residence times of 234Th in solution and of particulate 234Th were 130-247 days and 8.1-6.6 days, respectively. A high particle flux (1.23-5.03 g m-2 d-1) was calculated at this station. At the other two sites (11c and 15c), 234Th depth profiles are irregular, probably due to the release of dissolved 234Th by decomposing particles at certain depths, or to the contribution from lateral advection. Bulk mass fluxes measured by floating traps at stations 11c and 15c are very low (66-138 mg m-2 d-1). Also fluxes of organic carbon and nitrogen, and biogenic silica are reported for these two sites. The calculated fluxes are discussed with respect to methodologies and to the dynamics of the ice margin retreat.     

Soil carbon pools and fluxes after land conversion in a semiarid shrub-steppe ecosystem

Worldwide soil carbon (C) losses associated with agricultural expansion and intensification have contributed significantly to increased atmospheric CO₂. Soil disturbances resulting from land use changes were shown to modify the turnover of C and the formation of soil organic matter. A native semiarid shrub-steppe ecosystem recently converted into an irrigated agricultural development in the Columbia Basin of Washington State was evaluated for several abiotic indicators that might signal changes in an ecosystem during the initial stages of conversion and disturbance. Soil samples were collected in March of 2003 and 2004 from nine sites that included native shrub-steppe and agricultural fields converted in 2001 and 2002. Disturbance from conversion to irrigated crop production influenced total organic C and nitrogen (N) storage, C and N mineralization, and C turnover. Cultivated fields had greater concentrations of total organic C and N and higher cumulative C and N mineralization than native sites after 3 years of cultivation. Soil organic C was divided into three pools: an active pool (C _a) consisting of labile C (simple sugars, organic acids, the microbial biomass, and metabolic compounds of incorporated plant residues) with a mean residence time of days, an intermediate or slow pool (C _s) consisting of structural plant residues and physically stabilized C, and a resistant fraction (C _r) consisting of lignin and chemically stabilized C. Extended laboratory incubations of soil with measurements of CO₂ were used to differentiate the size and turnover of the C _a and C _s functional C pools. The active pools were determined to be 4.5 and 6.5% and slow pools averaged 44 and 47% of the total C in native and cultivated fields, respectively. Cultivation, crop residue incorporation, and dairy manure compost amendments contributed to the increase in total soil C.