An automated in-line clinical mastitis detection system using measurement of conductivity from foremilk of individual udder quarters

AIM: To assess a novel method for automatic in-line detection of clinical mastitis.

METHODS: For a brief period at the start of milking for each cow, electrical conductivity of foremilk was measured for each quarter in turn, using a single sensor installed in the long milk tube (LMT) about 1.5 m downstream from the milking-machine claw. Sequential separation of flow between udder quarters was achieved by control of pulsation to individual teatcups within a conventional cluster. The ratio of conductivity values between quarters was used as an indicator of mastitis status. The concept was evaluated initially in a pilot trial in a 200-cow herd milked in a 23-stall swing-over herringbone milking parlour. It was then tested rigorously in a field trial in a 640-cow herd milked in a 50-stall rotary milking parlour. Both trials were conducted in the Waikato region of New Zealand. In the latter trial, sensor results were compared with visual inspection of a commercial in-line mastitis filter fitted to each milking unit. These filters were inspected for clots immediately after every cow's milking, for 3 weeks. The dataset of approximately 27,000 individual milkings was tested against several published or potential alter- native ‘gold standards’ for diagnosing clinical mastitis.

RESULTS: In the pilot trial, 12–14 clinical events were detected out of 19 true clinical quarters, with a false-alert rate of between three and five false electrical-conductivity alerts per 1,000 individual milkings. In the more rigorous field trial, sensitivity ranged from 68 to 88%, and the false-alert rate (false-alert episodes per 1,000 individual milkings) ranged from 2.3 to 7.0.

CONCLUSION: The novel clinical mastitis detection system, based on separation of the flow and measurement of electrical conductivity from foremilk of individual udder quarters, has the potential to provide a new tool for helping farmers to monitor clinical mastitis in herds milked with conventional clusters.     

甘南牦牛与其他良种牛屠宰性能及牛肉食用品质对比分析

通过对甘南牦牛与鲁西黄牛、秦川牛、安格斯牛、夏洛来牛、西门达尔牛的屠宰性能和食用品质对比分析,结果表明,甘南牦牛在屠宰产肉性能的各项指标上,均低于其他良种牛;甘南牦牛肉色深红、大理石纹适中、pH值为5．55;甘南牦牛肉系水率为57．19％,比安格斯牛肉、西门塔尔牛肉分别低3．34％、3．90％,比秦川牛肉和鲁西黄牛肉分别高3．28％、3．37％;甘南牦牛熟肉率为69．79％,除比安格斯牛肉低之外,均高于秦川牛肉、鲁西黄牛肉及西门塔尔牛肉;甘南牦牛肉的剪切力值为4．85kg／cm2,比秦川牛肉略高,比鲁西黄牛肉、安格斯牛肉和西门塔尔牛肉低。     

青藏高原“黑土滩”退化高寒草甸草原的形成机制和治理方法的研究进展

高寒草甸是青藏高原天然草地的主体,也是我国最重要和面积最大的一个草地类型。“黑土滩”是高寒草甸退化的综合表现,对当地、我国甚至东南亚和南亚的生态安全和经济发展具有重大的影响。本文论述了高寒草甸生态系统的气候、土壤、植被和动物特点,全面综述了“黑土滩”退化草地的特征和表现,分析了导致“黑土滩”形成的诸因素及其形成的综合原因和机理,阐述了“黑土滩”对生态环境和草地畜牧业生产的不利影响和危害,提供了恢复和治理“黑土滩”退化草地的原则和具体技术方法。     

Strategies for mastitis control: dry cow therapy and culling

SUMMARY The effects of three selection strategies for dry cow therapy on prevention of new infections and rate of antibiotic usage were compared. Quarter infection status of 1044 cows in 12 herds was determined by bacteriological methods at drying off, calving and three to five months into the following lactation. Cows that were uninfected at drying off were randomly allocated to treatment (whole udder, dry cow therapy) and non-treatment groups. Infected cows were randomly allocated to whole udder or infected quarter only treatments. The strategies compared were blanket treatment (treat all quarters of all cows), selective cow treatment (treat all quarters of any cow infected in one or more quarters) and selective quarter treatment (treat infected quarters only). Selective cow treatment was identified as the preferred strategy. Blanket treatment resulted in increased antibiotic usage (15.5 vs 6.4 tubes per infection eliminated) with no additional benefit, and selective quarter treatment resulted in a higher new infection rate (6.4%vs 3.9% quarters) in the dry period. The prevalence of infection within a herd at drying off had no influence on new infection rates in the dry period or early lactation. The cure rate after dry cow treatment (mean of 66%) decreased significantly with increasing age (P < 0.001). Cows infected in the previous lactation contributed over 76% of infections at calving and nearly 70% at mid-lactation. To lower the incidence of mastitis in a herd, a greater emphasis on culling of older infected cows and prevention of new infections during lactation is needed.     

Prognostic factors for recovery from coxo-femoral dislocation in cattle

Details were recorded of 47 cases of coxo-femoral dislocation observed in cattle over 1 year. Treatment was successful in 20/47 (42.6%) cases using a method of closed reduction. Factors that most strongly influenced the prognosis were identified. The most useful single prognostic factor was whether the cow was able to stand before reduction. Other factors that also had a strong positive influence on the prognosis were: age less than 3y, bodyweight less than 400kg and duration of dislocation less than 12h. Nineteen unsuccessful cases were examined at the knackery. Four were found to have a fracture of the proximal femur. The coxo-femoral joint was carefully dissected in the other 15 cases and there was no evidence of hip dysplasia. A seasonal incidence of dislocations, which coincides with the calving and mating periods, was demonstrated during the survey and from practice records for the previous 3 years.     

Salmonella monitoring programs in Australian feed mills: a retrospective analysis

The availability of safe, commercially prepared stock feed for production animals is an important step in ensuring animal health and welfare and the safety of food animal products for human consumption. Animal feed quality assurance programs include microbiological monitoring of raw materials, mill equipment and finished feed. Over a period of 16 years, 23,963 samples for Salmonella culture and serotyping were collected from 22 stock feed mills. A multivariable generalized linear mixed model (GLMM) was used to identify mill and sample type factors that increase the odds of detecting Salmonella. The odds of detecting a Salmonella positive sample was greatest in samples from raw materials and in mills that processed restricted animal material (RAM). The percentage of positive samples ranged from 7.2% in 2003 to 2.8% in 2017. Of the 1,069 positive samples, 976 were serotyped with 61 different Salmonella serotypes isolated. The serotype most frequently isolated from raw materials was S. Agona, (n = 108) whilst S. Anatum was the serotype most frequently isolated from equipment and finished feed (n = 156). The diversity of Salmonella serotypes differed between mills and different stages of the production line. Microbiological monitoring in the commercial preparation of animal feed in Australian stock feed mills guides the implementation of quality control measures and risk mitigation strategies thereby reducing the prevalence and diversity of potentially zoonotic bacteria such as Salmonella, enhancing food safety for both animal and consumer.     

Optical chlorophyll measurements as predictors of total nitrogen,nitrogen fractions and in vitro ruminal nitrogen degradability in tropical grass forages

This study evaluated whether the FieldScout CM 1000 NDVI and Yara N–Tester models can produce accurate and reliable estimates of nitrogen (N), buffer-soluble nitrogen (BSN), buffer-insoluble nitrogen (BISN), non-protein nitrogen (NPN) and in vitro ruminal nitrogen degradability after 3, 12 and 24?h incubation (ND3, ND12 and ND24) in three tropical grasses: Brachiaria hybrid, Megathyrsus maximus and Paspalum atratum. Correlation between the Yara N-Tester and N, BISN and in vitro ruminal N degradability of the Brachiaria hybrid and M. maximus were high (r 0.67–0.83). The Yara N-Tester accounted for 81% and 86% (p 0.000) of N variability in the Brachiaria hybrid and M. maximus, respectively. The Yara N-Tester prediction models explained 72% and 70% (p 0.000) BISN variability in the Brachiaria hybrid and M. maximus, respectively. In vitro ND24 of the Brachiaria hybrid (R?2 0.75) and M. maximus (R?2 0.75) was also best predicted with the Yara N-Tester. Model validation showed generally low (≤0.90) concordance correlation coefficients except for Yara N-Tester N and ND24 in M. maximus. Random error was the main source of error. We conclude that the accuracy of the Yara N-Tester prediction models was superior to that of the FieldScout CM 1000 NDVI models, and that the Yara N-Tester can produce accurate and reliable estimates of Brachiaria hybrid and M. maximus N and M. maximus ND24.     

体外酶解法研究玉米的不同加工处理方式对过瘤胃淀粉小肠消化率的影响

本试验以体外酶解法来研究不同加工处理的玉米12 h瘤胃非降解残渣在小肠中的消化率。试验结果表明,不同加工处理方式对小肠淀粉消化率的影响不同,膨化加工可以显著提高过瘤胃淀粉的小肠消化率(P<0.05);烘烤、制粒、压扁以及焙炒加工处理对过瘤胃淀粉的小肠消化率没有显著影响(P>0.05)。     

Adaptation characteristics of mitochondria in plateau pikas at different altitudes

AIM: To investigate the adaptive characteristics of mitochondria in plateau pikas at different altitudes. METHODS: According to the altitudes of the capture area, plateau pikas were divided into 4 300 m group (Mado Star Sea, n=6) and 2 900 m group (Laoji Mountain South, n=6). The red blood cells and hemoglobin of the animals in 2 groups were measured. The levels of mitochondrial oxidative phosphorylation (OXPHOS) and fatty acid oxidation (FAO) in the liver and skeletal muscle, and mitochondrial H₂O₂ production level in the skeletal muscle were determined by high-resolution mitochondrial respirometer. RESULTS: The hemoglobin of the plateau pika in 4 300 m group was significantly lower than those in 2 900 m group. The liver state 4 respiration rate of mitochondrial respiratory chain complex I (CI-LEAK), mitochondrial respiratory chain complex I state 3 respiration rate (CI-OXPHOS) and respiratory chain complex I+Ⅱ state 3 respiration rate(CI+Ⅱ-OXPHOS), electron transfer capacity of respiratory chain complex I+Ⅱ (CI+Ⅱ-ETS), the electron transport capacity of the respiratory chain complex Ⅱ (CⅡ-ETS) in 2 900 m group were increased, and the coupling efficiency was decreased compared with 4 300 m group (P<0.05). The skeletal muscle CI-LEAK,CI+Ⅱ-OXPHOS and CI+Ⅱ-ETS were higher than those in 4 300 m group. Mitochondrial state 4 respiration rate with palmitic acid carnitine and malate as substrates (FAO-LEAK) of liver and skeletal muscle in 2 900 m group were increased compared with 4 300 m group. The skeletal muscle with palmitic acid carnitine as a substrate for fatty acid metabolism state 3 respiratory rate (FAO-OXPHOS) was increased in 2 900 m group compared with 4 300 m group. The H₂O₂/O₂ flow ratio (ΔH₂O₂) in 2 900 m group was lower in state 4 respiration rate of mitochondrial respiratory chain complex I (LEAK), state 3 of mitochondrial respiratory chain complex I (OXPHOS), state 3 of mitochondrial respiratory chain complex I+Ⅱ (OXPHOS*) and electron transfer capacity of respiratory chain complex I+Ⅱ (ETS) than 4 300 m group. CONCLUSION: Plateau pikas with different altitudes have different mitochondrial adaptation characteristics.     

H2O2对离体小麦叶片中蛋白质含量下降的影响

H2O2能氧化修饰离体小麦叶片蛋白质分子中的-SH基团,使蛋白质分子更容易被蛋白水解酶降解,表现为蛋白水解酶活力升高,蛋白质含量下降加快。随着H2O2浓度的增大,这一现象更加明显。