Sucking behaviour of hand-reared newborn dairy calves

AIM: To determine the feeding ability of calves during the first 4 days after birth.

METHODS: The sucking behaviour of 171 dairy calves, fed from individual bottles during the first 4 days after birth, was evaluated by quantifying the volume of colostrum consumed, the duration of feeding, and speed of drinking. Calves had been separated from their mothers and brought into a rearing shed in the morning, when <24 h of age, and were offered 2 L colostrum from a bottle in the afternoon of the same day, and twice daily thereafter.

RESULTS: Newborn calves became efficient suckers from bottles within 24 h of removal from their dams (collection). On the day after birth, 95% of calves drank the 2 L of colostrum offered during the afternoon feed, and by Day 4 virtually all calves (99%) drank this amount. Calves that had inadequate colostrum from their dam were more likely to drink all 2 L offered after collection, but a small number of calves that had not had colostrum from their dams and drank <500 ml at the afternoon feed following collection were likely not to drink 2 L on the following days. However, calves that did not drink all 2 L on Day 1 were not disadvantaged in comparison to those that did, in that they were equally likely to drink 2 L on Day 4.

CONCLUSIONS: The majority of calves became efficient drinkers within 48 hours of birth, but a small number of slow feeders may need individual feeding at least up to 4 days after birth.     

Long-term survival after combination chemotherapy for bilateral renal malignant lymphoma in a dog

CASE HISTORY: A 6-year-old, entire male Flat-coated Retriever was presented with a history of lethargy, polydipsia and seizures. Clinical chemistry had shown marked azotaemia.

CLINICAL FINDINGS AND DIAGNOSIS: Radiography and ultrasonography revealed bilateral renomegaly, and cytology of fine needle aspirates from the kidneys was diagnostic of malignant lymphoma. The dog was treated with a modified high-dose cyclophosphamide-, vincristine-, and prednisolone-based chemotherapy protocol, achieved remission, and returned to normal quality of life. Survival time was 346 days from the time of diagnosis.

CLINICAL RELEVANCE: Malignant lymphoma in the kidneys of dogs has been considered to carry a uniformly poor prognosis. Long-term remission after medical treatment has not previously been reported. The favourable outcome in this case illustrates the limitations of clinical staging in determining the outcome for individual patients.     

Antimicrobial Resistance in Some Gram‐Negative Bacteria Isolated from the Bovine Ejaculate

The bacterial load and degree of antibiotic resistance present in untreated and antibiotic‐treated semen samples were investigated in five bulls standing at a cattle‐breeding centre. Bacterial load was determined by colony counts from semen samples cultured on brain heart infusion and nutrient agar plates. Antibiotic resistance in these bacteria was assessed by measuring the diameter of bacterial growth inhibition zones around discs containing different concentrations of antibiotics. Representative antibiotic‐resistant bacterial isolates were selected for identification. Untreated semen contained few culturable bacteria, and all were completely sensitive to gentamycin, spectinomycin and lincomycin: six of the isolates showed some resistance to tylosin. In semen to which antibiotics had been added as part of the routine production process, two isolates were sensitive to all of the antibiotics tested, and the remainder were resistant to all. Resistant Gram‐negative isolates that were identified included Pseudomonas and Stenotrophomonas spp. both in the class Gammaproteobacteria and a Sphingomonas sp. which is in the class Alphaproteobacteria.     

Farmers’ Motivations to Plant and Manage On-Farm Trees in Ghana

Deforestation and forest degradation, especially in the agricultural landscapes, are serious threats to biodiversity conservation and sustainability of the timber industry. Planting trees on farms has been identified as having great potential to increase forest resources from agricultural landscapes. This paper examined farmers’ motivations and behaviour to engage in on-farm tree planting and management in Ghana by combining internal and external factors in a socio-psychological model. Data were collected from 156 smallholder farmers from five communities in two forest districts using a semi-structured questionnaire. Additional farm inventory data were collected from 33 farmers under two on-farm tree planting schemes. On-farm tree planting was perceived as providing income, access to personal timber for furniture, and access to loan facilities. Incentives such as provision of grants, farming inputs, capacity training, and access to markets for agricultural produce are factors that motivate on-farm tree planting in Ghana. The average standing volume of on-farm trees in the study area is 51.9 m³/ha which is almost twice the national average for the off-reserve areas in the semi-deciduous forests to which much of the study sites belong. Many farmers considered high financial costs and limited knowledge of appropriate techniques in managing planted on-farm trees as barriers to the development of tree stock on farms.     

Effect of N‐acetyl‐L‐cysteine Supplementation in Semen Extenders on Semen Quality and Reactive Oxygen Species of Chilled Canine Spermatozoa

The objective of this study was to evaluate the quality of chilled dog semen processed with extenders containing various concentrations of N‐acetyl‐L‐cysteine (NAC). Ejaculates from five dogs were collected, pooled and evaluated for concentration, motility, rapid steady forward movement (RSF‐movement), viability, acrosomal integrity and by the hypo‐osmotic swelling test (HOST). In addition, superoxide anion (O₂^‐?) production, hydroxyl radicals (OH^?) and total reactive oxygen species (tROS) were determined. The pool was divided into five aliquots, which were diluted to a final concentration of 66.66 × 10⁶ spermatozoa/ml with Tris‐glucose‐egg yolk extender containing one of the following concentrations of NAC (0, 0.5, 1, 2.5 or 5 mm ). The semen aliquots were chilled and preserved at 4°C. Semen quality was evaluated after rewarming at 72 h. Sperm motility was significantly higher with the 0.5 mm concentration compared with the control group (p = 0.001). Rapid steady forward movement was higher with the 0.5 and 1 mm concentrations compared with the control and 5 mm group (p < 0.001). Viability and HOST percentages were not significantly altered. Compared with the control, the 5 mm concentration showed significantly reduced percentages of spermatozoa with normal acrosomes (p = 0.049). None of the ROS values at 72 h were significantly affected by the presence of NAC in semen extenders, although all NAC concentrations showed lower O₂^‐? and OH^? values compared with the control. Only the concentrations of 1 and 5 mm inhibited the significant increase of tROS values after 72 h, compared with the fresh semen value. In conclusion, NAC supplementation of semen extenders is beneficial to semen motility of canine spermatozoa during chilling with the 0.5 mm concentration being the most effective, although no significant ROS inhibition was observed at 72 h.     

四川省农民培训意愿及影响因素分析

通过对四川省农民培训需求情况进行问卷调查,分析影响农民培训意愿的农民个体特征、农民家庭特征和农民对培训要素的选择等因素,研究发现这些变量对农民参与培训意愿在统计上有显著的影响,并在此基础上提出相应的政策建议。     

西洞庭湖区森林景观格局的生态敏感度研究与评价

采用主成分和灰色关联度方法,分析了西洞庭湖区森林景观格局与景观生态敏感的相关性,建立了森林景观格局生态敏感度评价指标体系。结果表明：（1）景规生态系统内部结构的不稳定性和对外界干扰的敏感性反映,体现了景观的敏感性程度;（2）森林景观格局的生态敏感度通过景观类型、地貌、坡度、土层厚度、年龄结构、郁闭度等级、群落结构来反映;（3）从森林景观类型的格局生态敏感度来看,灌木林、阔叶树类、经济林类、竹类最高,中等为杉木类、松木类,最低为非林地类;从评价等级来看,除了非林地外,所有的森林景观类型都为3以上,说明了全部为中等敏感度以上,这也反映了森林对外部环境干扰的敏感程度;（4）从区域的生态敏感度来看,生态敏感度最高的区域为桃源县和汉寿县,其次是临澧县、澧县和津市市,低度敏感区为安乡县、武陵区和鼎城区。     

An estimate of specificity for a Johne's disease absorbed ELISA in northern Australian cattle

Objective To estimate the specificity of an absorbed enzyme-linked immuno-sorbent assay kit^d for Johne's disease (JD) when used in mature cattle populations resident in northern Australia.
Design Blood samples were collected from beef cattle in northern Queensland, the Northern Territory and northern Western Australia, and from dairy cattle in northern Queensland. The specificity of a serological test for JD was estimated by testing the blood samples with an absorbed ELISA kit. Further samples were collected from cattle with positive ELISA results to determine the presence or absence of infection with Mycobacterium avium subsp paratuberculosis .
Procedure During 1995 and 1996, blood, tissue and gut contents were collected from beef cattle at abattoirs in Queensland and the Northern Territory; and blood and faecal samples were collected from dairy cattle in herds assessed to be most at risk for JD in northern Queensland. The blood samples were tested using an absorbed ELISA kit. Tissues and gut contents from beef cattle that had positive ELISA results were cultured for M avium subsp paratuberculosis , and tissues were examined histo-logically. Faecal samples from dairy cattle with positive ELISA results were cultured for M avium subsp paratuberculosis .
Results Estimates of specificity for this absorbed ELISA in mature northern Australian cattle were 98.0% (97.0 to 98.8%, 95% CI) in beef cattle, and 98.3% (96.7 to 99.3%, 95% CI) in dairy cattle.
Conclusion Estimates of specificity in this study were lower for beef cattle from the Northern Territory and northern Western Australia and for dairy cattle from northern Queensland than those quoted from studies on cattle in southern Western Australia. This should be considered when serological testing using the JD ELISA is carried out on northern Australian cattle.