Effects of antibiotic therapy at drying off on mastitis in the dry period and early lactation

Four strategies for selecting cows for intramammary therapy with benzathine cloxacillin at drying off were compared in 12 Victorian dairy herds. The bacteriological status of all quarters of all (1044) cows was determined just before drying off, within 2 d of calving, and again 3 to 5 months after calving. All cases of clinical mastitis (from calving to mid-lactation) were recorded. Cows not infected at drying off were allocated randomly to 2 subgroups of approximately 350 cows each: not infected, not treated (NI-NT), or not infected, all quarters treated (NI-AT). New infection rates in the dry period (3.8% for NI-NT vs 2.1% for NI-AT) and in early lactation (4.1% for NI-NT vs 3.9% for NI-AT) were low and these differences were not significant. Incidence of clinical mastitis in early lactation was almost 50% higher for the treated group of uninfected cows compared with the untreated group (0.05 less than p less than 0.1). Cows infected in one or more quarters at drying off were split randomly into 2 subgroups of approximately 170 cows each: infected, all quarters treated (I-AT), or infected quarters treated only (I-QT). The new infection rate during the dry period was nearly 4 times higher for I-QT (15.3%) due to significantly more new infections by Staphylococcus aureus and Streptococcus uberis.(ABSTRACT TRUNCATED AT 250 WORDS)     

A COMPARISON OF THE GROWTH AND COMPETITION BEHAVIOUR OF SEEDLINGS AND PLANTS FROM RHIZOMES OF AGROPYRON REPENS (L.) BEAUV. AND AGROSTIS GIGANTEA ROTH

Summary. Seedlings and plants derived from single-node rhizome fragments of Agropyron repens and Agrostis gigantea were grown in au unheated glasshouse, separately or together with wheat ( cv. Kolibri), in sandy loam soil in well-spaced pots, adequately watered and moderately fertilized. Samples of crop and weeds were taken for growth analysis in mid- May, late June and early August (when the wheat was ripe).
On average, wheat decreased the weight of weed shoots by 84% and of rhizomes by 77%, but the weeds decreased the weight of wheat shoots by only 7% and of grain by 13%. Without wheat, seedlings of both weed species had, by late June, grown as much as plants from rhizomes, but with wheat, the weed seedlings were throughout most of the experiment more susceptible to competition than were plants from rhizomes. There was no simple relationship between the final dry weights of the weeds and the amount they decreased wheat yield: although Agropyron seedlings in competition with wheat were much lighter than Agrostis from rhizomes, they decreased grain yield of wheat as much, suggesting that they competed more intensely for a limiting factor, possibly nitrogen.
It is concluded that the faster initial growth rate of wheat seedlings relative to the weeds from rhizomes and a larger initial seed reserve relative to the weed seedlings enabled the wheat to dominate the weeds.
Comparaison de la croissance et comportement compétitif de plantules et de plantes issues de rhizomes d'Agropyron repens ( L.) Beauv. et d' Agrostis gigantea Roth     

A STUDY OF THE COMPETITIVE ABILITY OF CHENOPODIUM ALBUM L.

Summary. Experiments arc reported that demonstrate that there is mutual interference between kale and Chenopodium album when grown in association. As the plants grow, those at high density, whether in mixtures or in pure stands, interfere with each other and individual plant weight and leaf area are reduced. By changing the time:of Introduction of one of the species into a mixture it was shown that kale suffered heavy mortality when C. album had an initial advantage. When kale was introduced before C. album the weed remained stunted but there was no mortality. The weed exerted an early effect of kale. The ability of C. album to interfere with kale, seems to be related to its plasticity. It is able to grow rapidly, to trap light effectively and even under adverse conditions to set seed.
Etude sur le pouvoir de compétition de Chenopodium album L. I. Recherches sur la compétition enire les choux et C. album     

VARIABILITY IN THREE AREAS OF THE DENCHWORTH SOIL MAP UNIT. III. SOIL GROUPING BASED ON CHEMICAL COMPOSITION

Data from a chemical determination of 21 elements plus seven Soil Survey routine laboratory measurements for three horizons of 30 soil profiles have been treated by multivariate techniques to find relationships and grouping of soil properties in soils mapped as Denchworth series. The samples profiles were developed in parent materials of Oxford, Kimmeridge and Gault clay origin. The Oxford clay grouping was confirmed, but the Kimmeridge and Gault clay soils were better represented by three rather than two classes.     

Packaged organic materials as monitoring tools for radionuclides

Pint-size perforated polyethylene bags were used as containers to test preserved tea, spinach, ion-exchange resin, live filamentous green algae, and dead filamentous green algae for the sorption and concentration of radionuclides from natural aquatic habitats and from a variety of laboratory controlled nutrient media. These packaged materials have been used to detect trace levels of radionuclides not found by the usual methods of analysis of the raw water itself for dissolved radionuclides.     

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。