Effects of organic manure and chemical fertilizer on soil fertility and productivity of plant and ratoon crops of sugarcane

A long-term field experiment was initiated in November, 1967 at Research Area of Department of Soil Science to study the response of nitrogen to pearl millet-wheat cropping system at various doses and modes of farmyard manure application. The soil organic carbon increased with farmyard manure application and ranged from 0.68% in control to 1.82% in the plot receiving the highest annual dose (90 Mg ha^?1) of farmyard manure. To study the contribution of farmyard manure on the productivity of pearl millet and wheat crops, the constants (intercept and slope) were determined between the grain yield of pearl millet and wheat crops with increasing dose of fertilizer nitrogen. Another linear regression was fitted between the intercept of the linear model and the soil organic carbon content. It has been observed that with each unit increase in the soil organic carbon, the productivity of pearl millet increased by 273 kg ha^?1 and that of wheat by 1591 kg ha^?1. The regression between the slope and soil organic carbon was linear in case of pearl millet (R² 0.49) but in case of wheat there was no relationship.     

Acceptability of various microparticulate diets to first-feeding walleye Stizostedion vitreum larvae

The acceptability of eight diets made by a wide variety of microparticulate manufacturing processes was studied using first-feeding walleye Stizostedion vitreum larvae. Diets were formulated using a common dietary mix but differed in manufacture technique. The microparticulate diets fed were (1) carrageenan bound, (2) alginate bound, (3) starch/konjack bound, (4) microextruded/maurmurized (MEM), (5) zein bound, (6) carboxymethyl cellulose bound (CMC), (7) particle-assisted rotationally agglomerated (PARA) and (8) a commercial microparticulate diet (Fry Feed Kyowa B-700, FFK). Controls were groups fed live Artemia nauplii and unfed. Gut fullness was measured as the cross-sectional optical area of the bolus visible through the transparent body of the larvae using computer-aided image analysis. Feeding incidence on MEM particles (71 ± 8%, mean ± standard error), zein-bound particles (69 ± 7%), alginate-bound particles (68 ± 2%) and PARA particles (65 ± 6%) were not significantly different ( P   0.05) from the feeding incidence for Artemia (71 ± 6%). FFK (49 ± 14%) and particles bound with carboxymethyl cellulose (27 ± 0.07%), starch (21 ± 10%) or carrageenan (20 ± 0.8%) had significantly ( P  < 0.05) lower feeding incidence. Larvae that did initiate feeding did not differ significantly ( P  > 0.05) in the amount of each microparticulate diet or Artemia consumed. This data indicates that once first-feeding walleye start on a diet, they will consume that diet to a similar fixed level of satiation. Given the differences in the amounts of water and nutrients in the various diets, more nutrients were delivered to the gut of walleye larvae feeding on microparticulate diets than on the Artemia control.     

Prevalence of anthelmintic resistance on sheep farms in New Zealand

AIM: To establish the prevalence of anthelmintic resistance in parasitic nematodes on sheep farms in New Zealand.

METHODS: A cross-sectional prevalence study was conducted, using a standardised faecal nematode egg count (FEC) reduction (FECR) test (FECRT) for ivermectin, at a full (0.2 mg/kg) and half (0.1 mg/kg) dose rate, and albendazole, levamisole and albendazole-levamisole in combination, on 60 lambs (n=10 per group) on farms selected from throughout New Zealand. Farms that conformed with selection criteria were chosen at random (n=80) or with a history of suspected resistance to macrocy- clic lactone (ML) anthelmintics (n=32). Resistance to an an- thelmintic was inferred when there was <95% reduction in FEC 7-10 days after treatment. Larval cultures were performed for all control groups and for treated groups for which resistance was evident.

RESULTS: Of the farms randomly selected, 36% showed ≥95% FECR for all anthelmintics tested; resistance to ivermectin at 0.1 and 0.2 mg/kg liveweight was evident on 36% and 25% of these farms, respectively. Resistance to both ivermectin (0.2 mg/kg) and levamisole was evident on 8/80 (10%) farms, to ivermectin and albendazole on 10/80 (13%) farms, and to iver- mectin, levamisole and albendazole on 6/80 (8%) farms. The prevalence of resistance to a half dose of ivermectin tended to be more prevalent on farms with a history of suspected ML resistance (p=0.06). Resistance to albendazole was seen across all the main parasite genera, and to levamisole in Nematodirus, Ostertagia (= Teladorsagia) and Trichostrongylus species. Resistance to ivermectin was dominated by Ostertagia spp, although Cooperia, Nematodirus and Trichostrongylus species were also implicated.

CONCLUSION: Anthelmintic resistance in parasitic nema-todes of sheep is common in New Zealand. Not only was resistance to albendazole and levamisole common, but resistance to the ML, ivermectin, was at a higher prevalence than expected. Sheep farmers and advisors in New Zealand need to re-evaluate the way they manage parasites, and more research is urgently needed if the steady decline in anthelmintic susceptibility is to be halted.     

Dermal absorption of pesticides in mice

The dermal penetration of 2,4-D, cyhexatin, fenvalerate, paraquat, maleic hydrazide, and captan was determined at 1, 6, and 24 hr after application to a 1.2-cm² area of the upperback of 7- to 8-week-old mice (1 mg/kg). The amounts of labeled pesticide were measured at the site of application and in the blood, liver, kidney, excreta, and carcass. Ninety-five percent, or greater, were recovered in all cases. These compounds were found to penetrate much slower (21% or less in 24 hr) than was shown for a group of insecticides (parathion, permethrin, carbofuran, and dieldrin, for example) in previous reports. Whereas slow penetration could be explained by low partition coefficients for most compounds, both fenvalerate and cyhexatin (high lipophilicity) were also found to have slow penetration rates. These compounds did not indicate any propensity for appreciable storage or binding in the tissues examined. The carcass contained the greatest amount of radioactivity at 24 hr. The fraction of each compound that penetrated was eliminated from the body at various rates with excretion being lowest for paraquat (50%) and highest for 2,4-D (93%) at 24 hr.     

Polyculture of the Giant Malaysian Prawn and the Golden Shiner in Southwestern Louisiana1

Juvenile prawns (Macrobrachium rosenbergii) were stocked at 37,050/ha and golden shiner (Noremigonus crysoleucas) fry at 321,100/ha into 16 earthen ponds at Rockefeller Wildlife Refuge, Grand Chenier, Louisiana. Four replicated treatments were tested: fed prawn monoculture, fed shiner monoculture, fed prawn and fed shiner polyculture, and unfed prawn fed shiner polyculture. The study lasted 149 days. There were no significant differences in growth between prawns fed in monoculture and prawns fed in polyculture (P > 0.05). However, fed prawns grew significantly larger (P < 0.05) than unfed prawns. Prawn survival in all treatments combined averaged 63%. Survival was significantly higher (P < 0.05) for fed prawns than for unfed prawns. Prawn yields averaged 533 kg/ha, when all treatments were combined. Yield was significantly higher (P < 0.05) for prawns grown with shiners and for prawns that received supplemental feed. Growth was significantly higher (P < 0.05) for shiners grown with fed prawns than for shiners grown with unfed prawns. Shiner survival averaged 33% and was significantly higher (P < 0.05) in monoculture than in polyculture. Yield for all ponds averaged 392 kg/ha, with no significant differences between treatments (P > 0.05).     

Evaluation of the efficacy of d-penicillamine and trientine as copper chelators using an in vitro technique involving ovine red blood cells.

An in vitro technique for haemolysing ovine red blood cells with copper sulphate was standardized to induce c 50% haemolysis with 0.5 mM CuSO4 after incubation for 14 h at 38 degrees C. This technique was then applied to test the efficacy of trientine and d-penicillamine in preventing haemolysis. Trientine concentrations of 0.5; 1.0 and 1.5 mM were found to be the most effective (P < 0.05) in reducing copper-induced haemolysis. One and 1.5 mM concentrations of d-penicillamine were also effective (P < 0.05), but in this experiment a 0.5 mM concentration failed to protect the erythrocytes.     

Effect of body condition score and reuse of progesterone‐releasing intravaginal devices on conception rate following timed artificial insemination in Nelore cows

This study had the aim of investigating the efficiency of timed artificial insemination (TAI) through the progesterone‐releasing intravaginal device (PRID), used in new condition and for the second and third times in Nelore cows. The effects of device reuse and body condition score (BCS) on the conception rate (CR) were evaluated in 1,122 multiparous Nelore cows (mean BCS of 2.7 ± 0.4), which were randomly distributed into three groups that received new (n = 330), once (n = 439) and twice used (n = 353) PRID. Among the 1,122 females that underwent TAI, 573 became pregnant, thus representing an overall CR of 51.06%. Cows with BCS between 2.75 and 4.0 had greater (p < .0001) CR (69.75%) than cows with BSC of 2.0–2.5 (32.98%). It was observed that the CR through using PRID was 60.00%, 51.71% and 41.93% for new, once and twice used PRID, respectively, with difference between all groups (p < .0001). Under tropical conditions, animals with BCS greater than 2.5 had a higher CR, and the CR decreased proportionally with the number of times that the PRID had been used.