Determination of silage face surface area on commercial California dairy farms

Analysis of exposed silage face surface area was conducted to better understand and provide feed management recommendations as well as evaluate potential compliance needs related to volatile organic compound emissions. Policy was developed by the San Joaquin Valley Air Pollution Control District (District) to restrict exposed surface area of silage piles to 199·7 m² per farm if only one pile was exposed or 399·5 m² per farm if more than one pile was exposed. Exposed surface area on piles of silages at 20 dairies was quantified to determine impacts of these surface area restrictions. Herd size ranged from 490 to 7,200 milking cows, and the number of exposed piles ranged from one to four per farm as maize and/or wheat silage. Surface area of piles was quantified based on pile measurements and geometric shapes. The measured value was compared to the estimated value using the District ‘online calculator’. The District calculator used inputs for base length and height with assumed constant relationships between base and top lengths. Five of 43 piles had >199·7 m² of exposed surface area. Sixteen of 20 dairies with more than one exposed surface complied with the exposed surface area restriction. On average, the District calculator overestimated surface areas by 11·6% ± 14·8 (range ?57·7 to 38·4%). Pile measurements and use of geometric shapes provide a more precise method to quantify exposed surface area. This will be of particular use for those operators who utilize the District calculator and find their exposed areas out of compliance.     

Evaluation of two dairy herd reproductive performance indicators that are adjusted for voluntary waiting period

Background

Overall reproductive performance of dairy herds is monitored by various indicators. Most of them do not consider all eligible animals and do not consider different management strategies at farm level. This problem can be alleviated by measuring the proportion of pregnant cows by specific intervals after their calving date or after a fixed time period, such as the voluntary waiting period. The aim of this study was to evaluate two reproductive performance indicators that consider the voluntary waiting period at the herd. The two indicators were: percentage of pregnant cows in the herd after the voluntary waiting period plus 30 days (PV30) and percentage of inseminated cows in the herd after the voluntary waiting period plus 30 days (IV30). We wanted to assess how PV30 and IV30 perform in a simulation of herds with different reproductive management and physiology and to compare them to indicators of reproductive performance that do not consider the herd voluntary waiting period.

Methods

To evaluate the reproductive indicators we used the SimHerd-program, a stochastic simulation model, and 18 scenarios were simulated. The scenarios were designed by altering the reproductive management efficiency and the status of reproductive physiology of the herd. Logistic regression models, together with receiver operating characteristics (ROC), were used to examine how well the reproductive performance indicators could discriminate between herds of different levels of reproductive management efficiency or reproductive physiology.

Results

The logistic regression models with the ROC analysis showed that IV30 was the indicator that best discriminated between different levels of management efficiency followed by PV30, calving interval, 200-days not-in calf-rate (NotIC200), in calf rate at100-days (IC100) and a fertility index. For reproductive physiology the ROC analysis showed that the fertility index was the indicator that best discriminated between different levels, followed by PV30, NotIC200, IC100 and the calving interval. IV30 could not discriminate between the two levels.

Conclusion

PV30 is the single best performance indicator for estimating the level of both herd management efficiency and reproductive physiology followed by NotIC200 and IC100. This indicates that PV30 could be a potential candidate for inclusion in dairy herd improvement schemes.     

BCG vaccination against tuberculosis in European badgers (Meles meles): a review

Tuberculosis (TB) is a significant animal health problem in many parts of the world, and reservoirs of infection in wild animals complicate disease control efforts in farmed livestock, particularly cattle. Badgers (Meles meles) are a significant wildlife reservoir of Mycobacterium bovis infection for cattle in the United Kingdom (UK) and Republic of Ireland (ROI). Vaccination of badgers using an M. bovis strain bacille Calmette-Guérin (BCG) vaccine could potentially be an option in the national TB eradication strategy. Wildlife vaccination has been used successfully for other diseases in wildlife species, and may have a role to play in reducing M. bovis transmission at the wildlife-livestock interface. Research to date has provided evidence that BCG is protective in badgers, and a parenteral badger BCG vaccine has been licensed in the UK. Further research is required to develop effective strategies for vaccine deployment and to determine the effect of badger vaccination on cattle TB incidence.     

Promoting fungal pigment formation in wood by utilizing a modified decay jar method

The role of test block placement within a modified decay jar system for promotion of fungal pigments was investigated. Beech and sugar maple blocks were inoculated with common pigment producing fungi and incubated for 10?weeks. Blocks were placed either below the vermiculite or resting on its surface; no feeder strips were utilized. Amount of pigmentation differed with block placement with Arthrographis cuboidea (on sugar maple and beech) and Xylaria polymorpha (only on sugar maple) producing more pigment when placed on the surface of the vermiculite. The differences in pigmentation, however, were not necessarily due to moisture content differences within test blocks, as moisture content did not vary significantly by block placement with A. cuboidea. Results indicate that placement of wood above vermiculite may increase pigmentation; however, reasons for the increase appear to differ among fungi.     

An improved estimate of leaf area index based on the histogram analysis of hemispherical photographs

Leaf area index (LAI) is a key parameter that affects the surface fluxes of energy, mass, and momentum over vegetated lands, but observational measurements are scarce, especially in remote areas with complex canopy structure. In this paper we present an indirect method to calculate the LAI based on the analyses of histograms of hemispherical photographs. The optimal threshold value (OTV), the gray-level required to separate the background (sky) and the foreground (leaves), was analytically calculated using the entropy crossover method (Sahoo, P.K., Slaaf, D.W., Albert, T.A., 1997. Threshold selection using a minimal histogram entropy difference. Optical Engineering 36(7) 1976–1981). The OTV was used to calculate the LAI using the well-known gap fraction method. This methodology was tested in two different ecosystems, including Amazon forest and pasturelands in Brazil. In general, the error between observed and calculated LAI was ～6%. The methodology presented is suitable for the calculation of LAI since it is responsive to sky conditions, automatic, easy to implement, faster than commercially available software, and requires less data storage.     

Effects of differing ground‐truth data,transect design and statistical analysis on the repeatability of hydroacoustic assessments of pollan Coregonus autumnalis pollan

Pollan, Coregonus autumnalis pollan Thompson, requires an appropriate standardised sampling protocol for conservation assessments. The suitability of hydroacoustics with gillnetting was evaluated, and the effects of sampling design, effort and statistical analysis on the repeatability of results were tested. Summer hydroacoustic surveys appear appropriate as pollan were not abundant in acoustically unsampled areas. However, pollan density estimates were significantly affected by the gillnet sampling design used to ground‐truth the acoustic data. Density estimates from the >12‐ m layer were more robust to gillnet design than estimates from the 3‐ to 12‐ m layer. Estimates from different transect designs yielded some statistically significant results. Comparison of transects common to both transect designs suggests that observed differences reflect temporal changes rather than transect design effects. The reduction in the systematic parallel transect effort by half significantly affected target strength distributions but not pollan density estimates. Density estimates were affected by statistical analysis method where pollan density was highest, with geostatistical analysis providing higher estimates than the arithmetic mean. Hydroacoustic assessments may provide a reliable index of pollan abundance over time and between lakes but future research should investigate the effects of temporal and abiotic factors.     

Corn Yield and Soil Fertility with Combined Use of Raw or Composted Beef Manure and Inorganic Fertilizers on the Texas Northern High Plains

About 7 million beef cattle are raised annually in the Texas High Plains, producing 16 million Mg of manure, which is land-applied as raw manure (RM) to crops. An interest in aerobic composting prompted a 2-year field study with the primary objective of evaluating corn (Zea mays L.) yield and soil fertility for RM as compared to composted manure (CM). The four treatments (TRT) consisted of low-rate composted manure (CM-L), high-rate composted manure (CM-H), RM, and inorganic fertilizer (IN). All four TRT received equal plant—available N by supplementing the RM and CM with IN. Yield was measured by both machine-harvesting and hand-harvesting methods. Machine-harvested yield was similar among TRT for both years. Hand-harvested yield was lower for IN than RM in the first year, with similar yields among TRT in the second year. Due to drought, yields were considerably lower in the second year for all TRT. After 2 years, CM-H had higher soil P, K, Zn, and organic carbon concentrations than IN, with no differences among TRT for soil NO₃-N, pH, or electrical conductivity. Both CM and RM provided beneficial nutrients for corn production and improving soil fertility. Land application of CM and RM provides long-term benefits to soil health and sustainability in the Texas High Plains region.