Season and location effects on serum and liver mineral concentrations of Senepol cattle on St Croix,virgin islands     

S. Wildeus  L. R. McDowell  J. R. Fugle 《Tropical animal health and production》1992,24(4):223-230

Summary Serum and liver concentrations of selected macro-and trace minerals were determined in Senepol cattle at 8 sites (4 each in a high and low rainfall region) during the dry and wet season on St Croix. At each site an average of 15 mature, lactating cows, grazing native grass/legume pastures without supplementation were blood sampled each season. Liver samples were collected (n=51) at slaughter from mature animals originating from the same sites. A preliminary analysis indicated no differences in serum mineral concentrations between mature lactating cows and growing heifers. There were differences between sites for serum magnesium (Mg) (P<0·001), copper (Cu) (P<0·05) selenium (Se) (P<0·001) and zinc (Zn) (P<0·01) in the dry season, and for Cu (P<0·01), iron (Fe) (P<0·001) and Zn (P<0·01) in the wet season. Higher (P<0·001) serum concentrations of Mg, Cu, Fe and Zn were observed in the dry season, while Se was higher (P<0·001) in the wet season. Liver concentrations of Cu and Fe were lower (P<0·01) and liver molybdenum (Mo) (P<0·001) and Se (P<0·05) higher during the dry season. The seasonal differences in serum Cu, Se and Zn concentrations have not been observed in other studies in the Central American region. More than 50% of serum samples were deficient in phosphorus (P) regardless of season, and in Cu and Zn during the wet season. Mineral supplementation should be considered.

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Resumen Se determinó la concentración de minerales (macro y trazas) seleccionados, en ganado Senepol en ocho sitios: cuatro de ellos en una región de alta precipitación y los otros cuatro en regiones de baja precipitación pluvial, durante la estación seca y lluviosa en la isla de Sta Cruz. En cada sitio, un promedio de 15 vacas lactantes, pastoreando pasto nativo y pasturas con leguminosas sin suplementación, se sangraron en cada estación. Se colectó tejido hepático (n=51) en el matadero local, de animales maduros provenientes de los sitios estudiados. Un análisis preliminar, no indicó diferencias en concentraciones séricas de minerales entre animales maduros lactandos y novillas en crecimiento. Hubo diferencias en cuanto a localización respecto al magnesio sérico (Mg) (P<0·001), cobre (Cu) (P<0·05) selenio (Se) (P<0·001) y zinc (Zn) (P<0·01) en la estación seca y para Cu (P<0·01), hierro (Fe) (P<0·001) y Zn (P<0·01) en la estación lluviosa. Se observaron concentracionas séricas màs altas (P<0·001) de Mg, Cu, Fe y Zn en la estación seca, mientras que el Se fue más alto (P<0·001) en la estación lluviosa. Las concentraciones hepáticas de Cu y Fe fueron bajas (P<0·01) y las de molibdeno hepático (Mo) (P<0·001) y Se (P<0·05), fueron altas durante la estación seca. Las diferencias estacionales en concentraciones de Cu, Se, y Zn sérico, no habian sido observadas en otros estudios en la región centroamericana. Mas de 50 por ciento de las muestras de suero fueron deficientes en fósforo (P) sin tener en cuenta la estación y en Cu y Zn durante la estación lluviosa. Se sugiere la necesidas de suplementación mineral.

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Résumé Les auteurs ont déterminé les concentrations sériques et hépatiques d'un certain nombre d'oligo éléments et de sels minéraux sur des bovins Senepol éléves sur 8 sites (quatre pour chaque région à forte et faible pluviométrie) pendant la saison humide et la saison sèche sur l'lle Sainte Croix. Sur chaque site, des prélèvements de sang ont été effectués pendant chaque saison sur la base d'une moyenne de 15 vaches adultes en lactation, paturant sur des parcours naturels de graminées/légumineuses, sans complémentation. Les prélèvements de foie (n=51) ont été collectés à l'abattoir sur des animaux adultes originaires de ces mêmes endroits. Une analyse préliminaire n'a indiqué aucune différence dans les concentrations minérales du sérum entre les vaches adultes en lactation et les génisses en cours de croissance. Il y avait des différences entre les sites pour le magnésium sérique (Mg) (P<0,001), le cuivre (Cu) (P<0,05), le sélénium (Se) (P<0,001) et le zinc (Zn) (P<0,01) en saison sèche et pour le cuivre (Cu) (P<0,01), le fer (Fe) (P<0,001) et le zinc (Zn) (P<0,01) en saison humide. En saison sèche, des concentrations plus élevées (P<0,001) on été observées pour Mg, Cu, Fe et Zn alors que le sélénium (Se) était plus abondant en saison humide. Les concentrations hépatiques en Cu et Fe étaient plus basses (P<0,01) mais celles en Molybdène (Mo) (P<0,001) et en sélénium (P<0,05) plus élevées au cours de la saison sèche. Les différences saisonnières entre les concentrations sériques de Cu, Se et Zn n'ont pas été observées en Amérique centrale par d'autres auteurs. Plus de 50 p. 100 des échantillons de sérum étaient carencés en phosphore (P) quelle que soit la saison, et en Cu et Zn pendant la saison humide. Il conviendrait de prendre en considération la complémentation minérale.

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The intensity of resistance by mature Merino ewes against Haemonchus contortus and Tichostrongylus colubriformis in single-species and combined-species infection     

DB ADAMS  JJ LYNCH†  BH ANDERSON  LR FELL‡  GN HINCH§  RK MUNRO¶ 《Australian veterinary journal》1990,67(12):443-445

Three-year-old, non-lactating and non-pregnant Merino ewes, raised on pasture under a program of strategic treatment with anthelmintic and found to be extremely resistant to "trickle" infection with Haemonchus contortus, were given single-dose infections with either H. contortus or Trichostrongylus colubriformis or both species together. The purpose was to ascertain the intensity of protective immunity against the 2 parasites in sheep with immunity acquired from a presumably slight exposure to infection. To provide a criterion, some infected ewes were immunosuppressed with corticosteroid, dexamethasone. Untreated ewes were extremely resistant to challenge infection with either 15,000 or 150,000 H. contortus or 15,000 T. colubriformis. Surprisingly, when mixed infection was given, egg counts for H. contortus were significantly elevated compared with infection by that species alone. Antibody to antigens from infective larval and adult H. contortus was measured in serum by enzyme-linked-immunosorbent assay (ELISA) during the course of infection. Serum titres against larval antigens were significantly depressed when infections with either H. contortus or T. colubriformis were permitted by immunosuppression with dexamethasone, whereas those against adult antigen were depressed when infection with T. colubriformis was permitted.  相似文献   

Ergovaline does not alter the severity of ryegrass staggers induced by lolitrem B     

SC Finch  JB Vlaming  BL Sutherland  C van Koten  WJ Mace  LR Fletcher 《New Zealand veterinary journal》2018,66(2):93-97

AIM: To investigate a possible interaction between lolitrem B and ergovaline by comparing the incidence and severity of ryegrass staggers in sheep grazing ryegrass (Lolium perenne) containing lolitrem B or ryegrass containing both lolitrem B and ergovaline.

METHODS: Ninety lambs, aged approximately 6 months, were grazed on plots of perennial ryegrass infected with either AR98 endophyte (containing lolitrem B), standard endophyte (containing lolitrem B and ergovaline) or no endophyte, for up to 42 days from 2 February 2010. Ten lambs were grazed on three replicate plots per cultivar. Herbage samples were collected for alkaloid analysis and lambs were scored for ryegrass staggers (scores from 0–5) weekly during the study. Any animal which was scored ≥4 was removed from the study.

RESULTS: Concentrations of lolitrem B did not differ between AR98 and standard endophyte-infected pastures during the study period (p=0.26), and ergovaline was present only in standard endophyte pastures. Ryegrass staggers was observed in sheep grazing both the AR98 and standard endophyte plots, with median scores increasing in the third week of the study. Prior to the end of the 42-day grazing period, 22 and 17 animals were removed from the standard endophyte and AR98 plots, respectively, because their staggers scores were ≥4. The cumulative probability of lambs having scores ≥4 did not differ between animals grazing the two pasture types (p=0.41).

CONCLUSIONS AND CLINICAL RELEVANCE: There was no evidence for ergovaline increasing the severity of ryegrass staggers induced by lolitrem B. In situations where the severity of ryegrass staggers appears to be greater than that predicted on the basis of concentrations of lolitrem B, the presence of other tremorgenic alkaloids should be investigated.  相似文献   

Management options to decrease phosphorus and sediment losses from irrigated cropland grazed by cattle and sheep     

R. W. McDowell  & D. J. Houlbrooke 《Soil Use and Management》2009,25(3):224-233

In southern New Zealand, grazing of forage crops is common practice to satisfy feed requirements of animals in winter when pasture growth is limited. This practice has been shown to cause soil physical damage and increased loss of surface water contaminants sediment and phosphorus (P) to water bodies. Strategies to mitigate the loss of sediment and P were trialled on a Pallic soil type (Aeric Fragiaquept) in the North Otago Rolling Downlands of New Zealand. All sites were irrigated and measurements were made of losses in overland and sub‐surface flow from intensive cattle or sheep grazed, winter forage crops, and sheep grazed pasture. Two mitigations (restricted grazing of crop to three hours and the application of aluminium sulphate) were assessed for their potential to decrease contaminant loss from cropland. Volumes of surface runoff and loss of total P, filterable reactive P and sediment showed significant differences (P < 0.05) between the control treatments (i.e. no mitigation) with cattle crop (88 mm surface runoff) > sheep crop (67 mm) > sheep pasture (33 mm). The contribution of irrigation water to overland flow water, as a result of saturation‐excess conditions, varied between treatments with more loss under cattle crop (20% of total) compared with sheep crop (15%) and sheep pasture (11%). These differences are probably an effect of soil physical condition and highlight the importance of accurate irrigation scheduling to keep soil moisture below field capacity. Restricted winter grazing and alum application after grazing significantly (P < 0.05) decreased P losses in surface runoff under cattle (from 1.4 to 0.9 kg P/ha) and sheep (from 1.0 to 0.7 kg/P/ha) grazed crop plots by about 30%. In cattle grazed plots, restricted grazing also decreased suspended sediments (SS) by 60%. The use of restricted grazing is suggested as a means of decreasing P and SS loss from grazed winter forage crops. The use of alum shows some promise for decreasing P losses, but requires further work to determine its long‐term effectiveness and use in other soils and management regimes.  相似文献   

Titres of precocene ii (6, 7-dimethoxy-2, 2- dimethylchromene) and its metabolites in the haemolymph of larvae of the african armyworm Spodoptera exempta (walker) following topical treatment with the compound     

Alan R. McCaffery  Phillip G. McDowell 《Pest management science》1987,19(3):185-196

No precocious metamorphosis or other morphogenetic effects were seen following topical treatment of fifth instar Spodoptera exempta with pre- cocene II. [3H]-Precocene II penetrated the larvae rapidly following topical application. An uptake of 47% was recorded in the first hour and an average of 27% for the first 3 h. Radioactivity in the haemolymph reached a maximum 4 h after treatment at 6–8% of the applied dose. A maximum titre of precocene of 1.1 × 10^?4 _M was observed 2 h after treatment and a biological half-life of around 1 h was recorded for the first 6 h. The metabolite precocene 11–3, 4-dihydrodiol appeared in the haemolymph with a maximum titre of 1.1 × 10^?4 _M at 4 h suggesting metabolism via the 3, 4-epoxide. At the same time an unidentified metabolite was observed possibly corresponding to the 6- and 7-(O)-desmethylated products described by others. Very large quantities of highly polar materials were observed in the haemolymph throughout the experiment and it is thought that these corresponded to conjugates. The evidence suggests that peripheral detoxication mechanisms do not operate sufficiently rapidly to prevent the establishment of a high titre of precocene. This, however, did not affect the corpora allata in this insect, whereas in a sensitive species that has been studied by other workers, necrosis of the glands would have resulted. Alternative explanations for insensitivity are discussed.  相似文献   

Effects of gossypol from cottonseed meal and dietary vitamin E on the reproductive characteristics of superovulated beef heifers     

Velasquez-Pereira J  Aréchiga CF  McDowell LR  Hansen PJ  Chenoweth PJ  Calhoun MC  Risco CA  Batra TR  Williams SN  Wilkinson NS 《Journal of animal science》2002,80(9):2485-2492

Superovulated Hereford-Angus crossbred heifers (average 397 kg BW) were used to test the effect of feeding cottonseed meal (gossypol) and vitamin E on embryo quality and ovarian characteristics. Twenty-four heifers were assigned randomly to four treatments with six heifers per treatment. Treatments were the following dietary supplements: 1) SBM (soybean meal + 30 IU vitamin E/kg of diet DM); 2) SBM+E (soybean meal + 4,000 IU vitamin E x animal(-1) x d(-1)); 3) CSM (cottonseed meal + 30 IU vitamin E/kg of diet DM); and 4) CSM+E (cottonseed meal + 4,000 IU vitamin E x animal(-1) x d(-1)). Supplements based on cottonseed meal provided 43.5 g of total gossypol/d (37% negative isomer (-) and 63% positive isomer (+)). Blood samples were collected at the start of the experiment and every 3 wk thereafter up to 12 wk. Plasma a-tocopherol (alpha-T) concentration was affected by treatments (P < 0.05). Heifers supplemented with cottonseed meal had greater (P < 0.05) alpha-T concentration in plasma than heifers supplemented with soybean meal at each concentration of vitamin E. Supplementation at 4,000 IU vitamin E x animal(-1) d(-1) increased (P < 0.05) the concentration of a-T in plasma. Weight gain, hemoglobin and hematocrit were not affected by treatment. Erythrocyte osmotic fragility (EOF) increased (P < 0.05) in cottonseed meal-fed animals; however, EOF was lowered (P < 0.05) with vitamin E supplementation. Heifers fed CSM and CSM+E supplements had greater (P < 0.01) concentrations of (-)-, (+)-, and total-gossypol in plasma, corpora lutea (CL), liver, and endometrium than heifers fed SBM and SBM+E supplements. Tissue alpha-T concentration increased with increased dietary supplemental vitamin E, particularly in great amounts in the CL. Because there was no adverse effect of gossypol on superovulation response or embryo development despite concentrations of gossypol in endometrium that are toxic to embryos, it is likely that systems exist in the reproductive tract to limit gossypol toxicity.  相似文献   

Effect of ammonium sulfate fertilization on bahiagrass quality and copper metabolism in grazing beef cattle   总被引：3，自引：0，他引：3  

Arthington JD  Rechcigl JE  Yost GP  McDowell LR  Fanning MD 《Journal of animal science》2002,80(10):2507-2512

To assess the impact of S fertilization on bahiagrass (Paspalum notatum) quality and Cu metabolism in cattle, two studies were conducted during the summer grazing season (1999 and 2000). Pasture replicates (16.2 ha; n = 2/treatment) received the same fertilizer treatment in each growing season, consisting of 1) 67 kg N/ha from ammonium sulfate (AS), 2) 67 kg N/ha from ammonium nitrate (AN), and 3) control (no fertilizer; C). Forage sampling was conducted at 28-d intervals following fertilization by the collection of whole plants (four samples/pasture) in randomly distributed 1-m2 grazing exclusion cages and analyzed for CP, in vitro organic matter digestibility, S, P, Ca, K, Mg, Na, Fe, Al, Mn, Cu, and Zn. To determine the effect of fertilizer treatment on liver trace mineral concentrations in grazing cattle, random liver tissue samples were collected (n = 12; four/treatment) at the start and end of the study period in 2000. Ammonium sulfate fertilization increased (P < 0.001) forage S concentration in both years. Plant tissue N concentrations were increased by N fertilization, regardless of source, in 2000, but not in 1999. Cows grazing AS pastures had lower (P < 0.05) liver Cu concentrations at the end of the study period in 2000 compared to AN and C. In Exp. 2, 37 Cu-deficient heifers grazing AS fertilized pastures were obtained from the same location and allocated to one of two treatments, consisting of supplements providing 123 mg/d of either inorganic (Cu sulfate; n = 12) or organic (Availa-Cu; n = 15) Cu. Treatments were delivered for 83 d. Liver Cu increased over time in all heifers regardless of treatment; however, heifers supplemented with Availa-Cu tended (P = 0.09) to have higher mean liver Cu concentrations than those receiving Cu sulfate. The results of these studies indicate that AS fertilization of bahiagrass increases forage S concentrations. When provided free-choice access to a complete salt-based trace mineral supplement, cows grazing AS-fertilized pastures had lower liver Cu concentrations than cows grazing pastures fertilized with AN; upon removal from high-S pastures, cattle were able to respond to Cu supplementation.  相似文献   

云南省曲靖市1995－2005年兽药质量抽检情况分析     

李芹  尹丽蓉  沈元春 《中国兽药杂志》2006,40(12):55-56,33

以曲靖市兽药监察所最近十年的兽药质量监督抽检报告为基础材料进行统计分析，反映兽药质量监督抽检工作情况及兽药质量状况。  相似文献   

人员在岗培训在实施兽药GMP现场管理中的作用     

宋立荣  康孟佼  郑雪花  李晶 《中国兽药杂志》2007,41(9):45-47

论述了对兽药生产企业进行人员在岗培训的必要性,对实施在岗培训的基本程序和应注意的事项进行了总结,旨在为兽药企业进行GMP现场管理提供参考。  相似文献   

Passive immunisation of neonatal lambs via colostrum and milk of ewes previously immunised with live attenuated Salmonella typhimurium protects neonatal lambs from experimental salmonellosis     

T.K.S. Mukkur  K.H. Walker  G.H. McDowell 《Comparative immunology, microbiology and infectious diseases》1998,21(4):327-336

Lambs sucking non-immunised ewes or ewes immunised 4-5 weeks before lambing with live attenuated, aromatic-dependent (aroA) Salmonella typhimurium (strain CS 332) were challenged orally at either 2, 4 or 7 days of age with virulent S. typhimurium (strain CS 94) at doses ranging from 10⁹ to 10¹³ colony forming units. No lambs displayed signs of clinical salmonellosis and all survived challenge but those sucking immunised ewes had organisms of the challenge strain in their faeces for much shorter periods of time than lambs of the control ewes. High titres of specific antibodies were measured in colostrum and milk of immunised ewes in comparison with very low titres measured in samples from control ewes; these differences were reflected by the titres of antibodies in the sera of corresponding lambs. At 2 days after lambing, the major antibody isotype in the colostrum of immunised ewes and sera of their lambs was IgM whereas at 7 days IgG1 was the predominant isotype. While it was clear that vaccination of pregnant ewes with the live attenuated vaccination conferred protection against experimentally-induced salmonellosis in their lambs, considerable protection was observed in control lambs in spite of there being very low titres of antibodies in the mammary secretion of their dams. The latter observation could be related to the presence of contain non-antibody potent bactericidal factors previously described in colostrum and milk.

Résumé

Des agneaux qui tètent des brebis non immunisées, ou bien immunisées, 4 à 5 semaines avant la mise bas avec un vaccin atténué constitué d'une souche de Salmonelle typhimurium dépendente pour sa croissance de la presence de composés aromatiques (souche aro A CS 332) ont reçu, à l'âge de 2, 4 ou 7 jours, par voie orale, des doses allant de 10⁹ à 10¹³ Salmonella (souche virulente CS 94). Aucun agneau n'a présenté de signes cliniques et tous ont survécu à cette administration, mais les agneaux des brebis immunisées ont excrété la souche d'épreuve dans leur fécès pendent moins longtemps que les agneaux des brebis non vaccinées. Des titres plus élevés d'anticorps sont détectés dans le colostrum et le lait des brebis vaccinées et comparés aux brebis témoins. Cette différence est également notée pour les titres d'anticorps présents dans le sérum des agneaux issus de brebis vaccinées ou non. Deux jours après la mise bas, la classe des anticorps majoritaires, tant au niveau du colostrum des brebis vaccinées que du sérum de leurs agneaux, est la classe des IgM, alors qu'après 7 jours, les IgG1 prédominent. Bien qu'il soit clair que des brebis pleines vaccinées à l'aide d'un vaccin vivant atténué, apportent à leurs agneaux une protection vis à vis d'une Salmonella expérimentale, une réelle protection est également observée chez les agneaux témoins, malgré les titres faibles d'anticorps présente dans les sécrétions mammaires de leur mères. Cette dernière observation peut être mise en rapport avec la présence d'agents bactériodes ne contenant pas d'anticorps, déjà décrits dans le colostrum et le lait.  相似文献