Veterinary research at ruakura today

Extract

The labelling with the term “alchemy” in a recent Veterinary Record of the group of biochemical tests known as a “metabolic profile” should not be allowed to discredit all biochemical tests aimed at monitoring herd health. This paper will mention some which already have value in disease control and others will undoubtedly emerge.     

The detection of Brucella ovis infection in rams

Abstract

Extract

Each year in New Zealand, many rams are palpated for lesions of the epididymes and testes. Although regarded initially as a method of detecting infertile rams (Crawford and James, 1950 Biberstein, E. L. and McGowan, B. 1958. Cornell Vet., 48: 31–31.  [Google Scholar]), the technique is now regarded primarily as a method of detecting infection with the organism for which Buddie (1956 Buddle, M. B. 1956. J.Hyg., 54: 351–351.  [Google Scholar]) proposed the name Brucella ovis.     

Surfactant effects on application of a hydrophobic, fluoropolymer coating to cotton by admicellar polymerization

Various methods have been used previously to impart hydrophobicity to cotton. In this study, thin co-polymer films of trifluoroethyl acrylate (TFEA) and octafluoro pentyl methacrylate (OFPM) were formed on cotton using individual fluorosurfactants and surfactant mixtures through the process of admicellar polymerization. Efficacy of 6 different fluorosurfactant systems and process conditions including surfactant type, concentration, adsorption/adsolubilization time, polymerization time, and monomer concentration have been investigated in order to obtain hydrophobic coatings on woven cotton fabric. Adsolubilization times as short as 2 h and polymerization times as short as 1 h yielded satisfactory performance. Characterization of the hydrophobic polymer films obtained included static contact angles, SEM imaging, elemental analysis and XPS analysis. Treated fabrics exhibited good water repellency for several surfactants and surfactant mixtures with initial supernatant monomer concentrations of 4 mM. Surfactant mixtures were able to outperform the separate individual species in admicellar polymerization.     

ECONOMIC RISK ASSESSMENT OF A SEMI-INTENSIVE SHRIMP FARM IN SINALOA,MEXICO

In Mexico shrimp farming is the most important aquaculture activity. However, its sustainable development has been threatened in recent years by the economic risk associated with low yields caused by outbreaks of viral diseases. A stochastic bioeconomic model was developed to analyze the economics of farm management adjustments as a response to disease risks, using pond-level data from a farm operating in the State of Sinaloa, Mexico, during the period 2001–2005. The data base analyzed included different combinations of stocking density (in the range 6–30 PL/m²) and culture time (from 12 to 31 weeks), which allows for wider application of the simulation results, even at the industry level. Results from this study indicate that operating costs would increase by 33% if the farmer would choose to market product directly. Scenarios with lower stocking densities and intermediate culture times generated the highest probabilities 6–9 PL/m² 16–19 weeks (76%/100%/70%), and 10–14 PL/m² 20–24 weeks (72%/99%) of achieving superior economic performance, as demonstrated by achieving the target reference point of 35% operating profit margin ratio. The study reinforces the value of the current trends in Sinaloa to reduce stocking density as a good management practice to decrease the impact of diseases. This study also provides important additional knowledge on the specific economic results and risks associated with the combination of these two management variables at different levels.     

CREDIT MANAGEMENT ANALYSIS OF SEMI-INTENSIVE SHRIMP FARMING IN MEXICO

Credit management (funding source with its specific interest rate, its timing, and amount) and its trade, affect feasibility of commercial shrimp farming. To analyze optimal trade credit management, an existing bioeconomic model of a semi-intensive shrimp farm (139 hectares with 44 earthen ponds) located in Sinaloa, Mexico, was extended to create a framework that assesses the decision-making problem related to funding from input suppliers (feed and postlarvae) during one culture cycle, integrating stochastic factors like shrimp mortality and pond water temperature. Through the application of Monte Carlo simulation and genetic algorithm-based optimization techniques, results show that the minimum funding cost is US$15,710 (for an operation budget of US$603,790), 27% lower than alternative funding scenarios (P-value <0.001). Although framed at the firm level, this approach optimizes any funding planning scenario in short-term credit management, particularly in funding schemes involving input suppliers. Further research is needed to relate credit management at the firm level with other elements of the value chain.     

Environmental Fate of the Herbicide MCPA in Two Soils as Affected by the Presence of Wheat Ash

Water, Air, & Soil Pollution - This study was conducted to evaluate the environmental fate processes of the herbicide (4-chloro-2-methylphenoxy)acetic acid (MCPA) in agricultural soils in the...     

Yield formation of five crop species under water shortage and differential potassium supply

A long‐term field experiment on a Haplic Phaeozem, established 1949 with four levels of potassium (K) supply (5, 69, 133, and 261 kg K ha^?1), was analyzed for the interaction between K supply and yield loss of five crop species by water shortage. The crop species were cultivated simultaneously side‐by‐side in the following rotation: potato (Solanum tuberosum L.), silage maize (Zea mays L.), spring wheat (Triticum aestivum L.), beet (Beta vulgaris L.), and spring barley (Hordeum vulgare L.). The treatment with 133 kg K ha^?1 supply had a nearly balanced K budget. In the treatments with lower supply, the soil delivered K from its mineral constituents. On the low‐K plots (especially on those with only 5 kg K ha^?1), crops suffered yield depressions of nearly all main harvest products (cereal grains, potato tubers, beet storage roots, silage maize) and by‐products (straw, beet leaves) by up to 40.7% of dry matter. Only wheat grains were an exception. Potassium concentrations in the harvested plant parts decreased nearly in parallel to the reduction of their dry matter yields, with the exception of cereal grains, which kept stable concentrations even in the treatment with only 5 kg K ha^?1. A comparison of four year‐pairs with differing levels of precipitation in yield‐relevant periods showed an average water shortage‐induced depression of dry matter yields by 19.7% in the main harvest products. The severity of this yield depression was not mitigated by elevated K supply, with the exception of beet leaves, where the dry matter production was stabilized by high K supply. In this crop, the reduction of storage‐root yield was associated with a decrease in harvest index and was therefore obviously caused by an inhibition of assimilate translocation from the leaves into these organs, in contrast to cereals, where water shortage primarily affected dry matter production in vegetative organs. It is concluded that the physiological causes of yield reduction by drought stress and the possibility of its amelioration by K supply differ between plant species and organs.     

Milk Yield of Holstein Cows Induced into Lactation Twice Consecutively and Lactation Curve Models Fitted to Artificial Lactations

Nineteen multiparous barren Holstein cows were subjected to an induction of lactation protocol for 21 d administering estradiol cypionate (2 mg kg⁻¹ of body weight (BW) d⁻¹, on day 1 to 14), progesterone (0.10 mg kg⁻¹ of BW, on day 1 to 7), flumethasone (0.03 mg kg⁻¹ of BW, on day 18 to 20) and recombinant bovine somatotropin (rbST; 500 mg per cow, on day 1, 6, 16 and 21). At the end of lactation and with a minimum of a 2-mon dry period, the same cows were again hormonally induced into lactation. Cows in both lactations were not artificially inseminated, they were milked 3 times daily and received rbST throughout lactation. Mean accumulated milk yield at 305 d in milk (DIM) did not differ between the first and second induced lactations ((9 710 ±1 728) vs. (9 309±2 150) kg; mean±SD). Total milk yield ((12 707±3 406) vs. (12 306±4 218) kg; mean±SD) and lactation length ((405±100) vs. (410±91) d; mean±SD) were not different between the first and second induced lactations. In a second study, 15 empirical models including exponential, power law, yield-density, sigmoidal and miscellaneous models were compared for their suitability by modeling 12-mon (n=334), 18-mon (n=164) and 29-mon (n=22) lactation cycles of Holsteins cows induced into lactation and treated with rbST throughout the lactation. Hoerl (Y= ab^1/xx^c), Wood (Y=ax^b exp(cx)) and Dhanoa (Y=ax^(bc)exp(cx)) models were equally suitable to describe 12-mon lactations. An exponential model with five parameters (Y=exp(a+bx+cd²+e/x)) showed the best fit for milk yield for 18-mon lactations. The rational model (Y=a+bx/1+cx+dx²) was found to produce the closest fit for 29-mon lactations. It was concluded that, with the protocol used in the present study, multiparous cows respond favorably to a second cycle of induced lactation, with milk yield similar to that experienced during the first cycle. Thus, dairy producers might be able to lengthen the productive life of infertile high producing cows with a renewal of artificial lactation, which would imply an overall reduction in voluntary culling of cows. Also, various equations used to describe the lactation curves demonstrated the potential for fitting monthly milk records of Holstein cows with prolonged lactations and induced hormonally into lactation.