摘要:

The objective of the study was to determine the prevalence of mastitis among primiparous heifers at calving and at drying off in 11 Waikato dairy herds during the 1993–94 dairy production season. Duplicate quarter milk samples were collected aseptically from 458 heifers within 5 days after calving for bacteriological analysis. Mastitis was diagnosed in at least one quarter in 35.6% of these heifers. Coagulase-negative staphylococci were isolated from 21.8% of the heifers. The prevalence of coagulase-negative staphylococci varied between herds from 4.3% to 44.8%. Environmental streptococci caused mastitis in 12.2% of heifers, ranging from 5.6% to 24.1% between herds.Streptococcw uberiswas the pathogen identified most frequently at calving and accounted for more than 90% of the streptococcal isolates.Streptococcw uberisand coliforms were isolated from less than 1% of samples. Clinical mastitis was observed in 8.1% of heifers at calving; environmental streptococci were isolated from 67.6% of these clinical cases. Only 2.8% of heifers developed clinical mastitis during lactation and environmental streptococci were isolated from 38.5% of these cases. The prevalence of mastitis among 428 of the heifers at drying off was 64.7%; a 1.8 fold increase during lactation.Corynebactetium boviswas isolated from 43% of heifers at drying off even though it was not isolated from any heifers at calving. During the season, the prevalence ofStaphylococcus aureusmastitis increased to 2.8% while mastitis caused by environmental streptococci declined to 2.8%. The prevalence of environmental mastitis pathogens decreased during lactation while contagious pathogens increased in each of the 11 herds. Ineffective post-milking teat sanitation probably contributed to the increase in mastitis caused by contagious pathogens. Specific factors were not determined that affected the variation in prevalence between herds.

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35932

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Lambs at 4–5 weeks of age were studied during the first 4 hours after castration and/or tailing using three methods in various commonly used combinations. The methods were: cutting with a knife, application of constricting rubber rings and using a heated docking iron (tailing only). Behaviour was monitored by quantifying the incidences of restlessness (during the first hour only), normal and abnormal standing/walking, and normal and abnormal lying. Plasma cortisol concentrations were also measured in samples taken at intervals during the 4 hours after treatment. With the knife, abnormal standing/walking predominated throughout the fist 4 hours and beyond, and restlessness was virtually absent. Plasma cortisol concentrations in knife-treated lambs remained above pretreatment values for at least 4 hours. With rings, high restlessness was invariably present during the first 30–45 minutes, and much of the associated standing/walking and lying was abnormal, but all behaviours had returned to control values within 4 hours of treatment, as had the plasma cortisol concentrations. There were no correlations between the incidences of abnormal behaviours and the plasma cortisol concentrations during the first 4 hour after any treatment, except that when abnormal behaviour was present the cortisol concentrations were greater than pretreatment values, and vice versa. Thus, the presence/absence of the abnormal behaviours reported here allowed an assessment of the duration of distress after castration and/or tailing. However, as the behavioural responses to castration and/or tailing were broadly procedure-specific, so that the responses to the knife and rings were not apparently part of the one behavioural continuum, it is argued that the relative intensities of distress caused by the two procedures cannot be assessed from behaviour alone. Rather, reference must also be made to established physiological indices of distress such as plasma cortisol concentration. On that basis, the knife treatments apparently caused greater and more protracted distress responses than did the ring or docking iron treatments, and should therefore be avoided. However, ringtreated lambs. especially those castrated or castrated and tailed, apparently experienced distress, so that more benign alternatives to the use of rings should also be sought.

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35933

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Three dressing practices were assessed in traditional lamb carcass dressing systems for their ability to improve control of microbiological and visible contamination. The routine removal of a piece of skin from the perineal area reduced total aerobic plate counts andEscherichiu colicounts on carcasses derived from both woolly and shorn groups of lambs. Similar results were found when the “Y-cut” was delayed in the dressing sequence, butE. colicounts increased slightly in one group. The use of a wide-blow shear prior to the opening cut on the hindleg of carcasses derived from woolly lambs resulted in a slight increase in the microbiological contamination on the leg. The removal of a piece of skin from the perineal area reduced scores for faecal contamination despite a small increase in contamination with wool. Changes in visible contamination in response to the two other dressing procedures were principally effected through changes in levels of contamination with wool. Irrespective of dressing procedures, levels of microbiological and visible contamination were lower on carcasses derived from shorn compared with woolly lambs. These studies demonstrated that, although they are reasonable indicators, the use of parameters of visible contamination as a measure of carcass hygiene must be treated with caution. This is especially the case if a genuine HACCP-based system for the control of dressing hygiene for a particular class of slaughtered livestock is to be implemented.

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35934

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Abortions due toCampylobacter fetus fetus (C. fetus fetus)were diagnosed in three Canterbury ewe flocks 6 weeks prior to lambing. In two of the flocks, two inoculations of aC. fetus fetusbacterin, 10 days apart, reduced the incidence of abortions in the treated ewes to about one third and one half respectively of the level in the control ewes in the same flock. The treatment had no effect in a third flock where an outbreak had been in progress for 2 weeks before investigations started. The results confirm earlier Scottish work where pregnant sheep were inoculated with aC. fetus fetusvaccine following artificial challenge withC. fetus fetus. This inoculation significantly reduced the number ofC. fetus fetusabortions. The results also indicate that treatment must start very early in an outbreak.

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35935

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

An experimental, trivalent, bovine, leptospiral vaccine, containing inactivatedLeptospira interrogansserovarspomonaandcopenhageniandL. borgpeterseniiserovarhardjoHardjobovis, was developed. The experimental vaccine was shown to protect hamsters against virulent challenge with each of the component serovars. In a serological efficacy test in cattle, the experimental vaccine was compared for bioequivalence with a similar product, registered in New Zealand for veterinary use. The experimental vaccine induced higher titres in cattle than the latter mentioned product.

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35936

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper documents a disease of Border Collies characterised by chronic neutropenia which probably resulted in recurrent bacterial infections manifesting as osteomyelitis and sometimes gastroenteritis. The neutropenia occurred despite hyperplasia of the myeloid cells in the bone marrow and a “shift to the right” in myeloid cell maturation. The underlying defect is currently unknown but may result from the inability of neutrophils to escape from the bone marrow into the peripheral circulation. Necrosis and new bone formation commonly involved the metaphyseal regions of long bones. Other findings included a fasting hypercholesterolaemia and the occasional presence of nucleated red blood cells in circulation, despite a non-regenerative anaemia. An autosomal recessive mode of inheritance is suspected. This condition has some features of a rare human disease called myelokathexis which is also believed to have in autosomal recessive mode of inheritance.

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35937

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Larval cultures were used to determine the identities and occurrences of those parasites (excludingNematodirus) represented by strongylid eggs at the time of anthehnintic administration in ovine faecal egg count reduction tests submitted to the Batchelar Animal Health Laboratory between 1992 and 1994. The numbers of individual nematode genera recorded in pre-treatment samples from these cases ranged from one to five and included infections ofHaemonchus,Ostertagia,Trichostrongylus,CooperiaandOesophagostomum/Chabertia. Adequate egg representation for testing purposes by all five genera simultaneously was found to occur in only 17 (10%) of the 163 cases examined, with the majority (71%) of them containing between one and three nematode genera. The greatest representation occurred in those tests conducted during the months of February to May. However, even during this period, worm eggs of all five genera were concurrently present on only 16% of occasions.

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35938

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Extract

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35939

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Extract

ISSN:0048-0169    

DOI:10.1080/00480169.1996.35940

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor