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Query: UMLS:C0851341 (infestation)
 10,121 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Crossbred calves (Bos taurus x Bos indicus) were repeatedly infested with the ixodid tick, Hyalomma anatolicum anatolicum. The parameters of engorgement, pre-oviposition period, oviposition period, engorged weight, egg batch weight, and per cent hatch of eggs all showed statistically significant differences between first to tenth infestation. Only the time to engorgement did not change. It is concluded that repeated infestations of this tick stimulate acquired resistance.
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PMID:Attempted immunisation of crossbred calves (Bos taurus x Bos indicus) by repeated natural attachment of ticks Hyalomma anatolicum anatolicum Koch (1844). 179 26

Two Bos taurus calves were made resistant to tick infestation by exposing them to approximately 500 rabbit-reared nymphs of Hyalomma anatolicum anatolicum twice at a 2-week interval. These two calves, together with a tick-susceptible control calf, were inoculated with a stabilate of Theileria annulata (Ankara). Patent infection resulted in all three calves. Seven-hundred and fifty gerbil-reared nymphs were then applied on each of these calves as well as another tick-susceptible calf that was Theileria free. This infestation was carried out on Day 8 post-inoculation. Ticks that dropped on Day 13 post-inoculation were examined to note the development of T. annulata in them and the histological changes that occurred in the gut and salivary glands. During the second phase of feeding, the gut epithelia of the ticks from the tick-resistant calves were less active. There were no notable differences in the characteristics of the developmental stages of T. annulata between the ticks from the tick-resistant calves and those from the susceptible calf. However, ticks from one calf that acquired a higher level of tick resistance were significantly less susceptible to infection by T. annulata. Bovine tick resistance therefore compromises the vector capacity of H. a. anatolicum and this may be of epidemiological significance in the endemic areas of tropical theileriosis.
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PMID:The effects of bovine tick resistance on the susceptibility of Hyalomma anatolicum anatolicum to infection with Theileria annulata (Ankara). 210 19

Controlled repeated infestation of Bos taurus and Bos indicus cattle resulted in a decline in the recovery of all R. appendiculatus instars. Resistance to infestation varied between individuals although all individuals manifested severe hypersensitivity at the attachment site, which was reflected in the grooming reflex.
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PMID:Immunity of the ox to the brown ear tick Rhipicephalus appendiculatus. 230 71

Bos taurus calves free from tick-borne diseases were prophylactically treated with oxytetracycline hydrochloride and phenamidine isothionate 40% (w/v) injections and infested twice with adult Rhipicephalus appendiculatus ticks. Mono- and diphasic temperature rises were observed during primary and secondary exposures respectively with the peak occurring when the ticks were completing engorgement. However, the first rise in the secondary infestation occurred well before repletion and was associated with a hypersensitivity state. The feeding performance, viability and fecundity of female ticks were impaired during the secondary exposure.
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PMID:Pyrexia in response to Rhipicephalus appendiculatus infestation in calves. 708 Feb 5

In the reaction of Bos taurus cattle to infestation by the tick Boophilus microplus, mast cell histamine is translocated by the eosinophils to the attachment site. The concentration pattern of this cutaneous mediator for pain appears related to the grooming behaviour of the host.
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PMID:A putative role for eosinophils in tick rejection. 720 67

A survey by mail was used to determine the views of beef producers in the Boophilus microplus endemic area of Queensland on the control of and vaccination against tick fever. Data from 448 questionnaires were analysed, representing 2.7% of beef producers in the survey area. Producers considered buffalo fly (Haematobia irritans exigua) infestation as the most important problem whereas tick fever ranked sixth overall. Private veterinarians were regarded as the most important source of information on vaccines for cattle followed by a weekly rural newspaper. From the survey we estimate that about 33% of producers used the tick fever vaccine produced by the Tick Fever Research Centre of Queensland Department of Primary Industries but there were significant (P < 0.05) variations between regions and herds. Large herds (> or = 400 head) in south-east Queensland were the most likely to be vaccinated against tick fever. Of the producers who did not use the vaccine, over 70% replied that there was no need to vaccinate because of the low risk of the disease in their herds. In 52% of unvaccinated herds the treatment of animals with acaricide was considered the most important means of tick fever control and 61% of these herds comprised Bos indicus x Bos taurus or Bos indicus cattle.
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PMID:A survey of cattle producers in the Boophilus microplus endemic area of Queensland to determine attitudes to the control of and vaccination against tick fever. 761 88

Nine yearling crossbred beef steers, Bos taurus L., were used to examine physiological responses to Gulf Coast tick, Amblyomma maculatum Koch, infestation. Steers were stanchioned indoors in individual environmentally controlled rooms. On day 0, each animal received 0, 25, or 75 pairs of ticks. Physiological variables measured daily were feed intake, heart rates, rectal temperatures, and respiration rates. Blood samples were collected from each animal on days 7, 21, and 42 for serum constituent analysis. To monitor metabolic hormone status, intensive blood samples were collected hourly for 6 h on days 21 and 42. Throughout the treatment period, feed intake values were similar among treatments resulting in comparable body weight at the end of the trial. Heart rates and rectal temperatures were unaffected, however, respiration rates of steers infested with 25 pairs of ticks were higher than the other treatment groups. Treatment effects were detected in uric acid concentrations on day 7 in steers infested with 75 pairs of ticks. Treatment effects were detected in total, direct and indirect bilirubin, gamma-glutamyl transpeptidase, and aspartate amino transferase concentrations. Likewise, creatine kinase concentrations were higher in the tick-infested steers on day 7. Elevated white blood cell counts were observed in tick-infested steers. All other serum components were similar and were within their normal ranges. Serum insulin, prolactin, growth hormone, and cortisol concentrations were unaffected by tick infestations. Gulf coast tick infestation resulted in altered blood composition indicative of infection caused by tick feeding habits.
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PMID:Physiological responses of beef cattle to Gulf Coast tick (Acari: Ixodidae) infestations. 772 83

Nine yearling crossbred beef heifers, Bos taurus L., were used to examine physiological responses to horn fly, Haematobia irritans (L.), infestation. Heifers were stanchioned indoors in individual environmentally controlled rooms. On day 0, each animal received 0, 500, or 1,000 horn flies. Fly numbers were adjusted daily to maintain an appropriate infestation for each heifer. Feed intake, respiration rate, and rectal temperature was recorded daily. In addition, blood samples were collected from each animal on days 0, 12, and 33 for serum constituent analysis. To monitor metabolic hormone status, intensive blood samples were also collected hourly for 6 h on days 0, 12, and 33. Throughout the period of treatment, feed intake values were similar among treatments resulting in comparable body weight at the end of the trial. Respiration rates on each day were similar among groups. Rectal temperature was also unaffected by horn fly infestations. Serum electrolyte analysis revealed that neither Na, K, Cl, Ca, P, nor Fe differed among treatments. Likewise, HCO3/CO2 ratio, anion gap, and serum osmolality did not differ among treatment groups. Major indicators of nutrient status (glucose, cholesterol, triglycerides, urea N, creatinine, uric acid, albumin, globulin) and insulin, growth hormone, and prolactin were also unaffected. Serum bilirubin and enzyme (alkaline phosphatase, creatine phosphokinase, gamma-glutamyl transpeptidase, lactic dehydrogenase, aspartate amino transferase, alanine amino transferase) concentrations were similar in control heifers and those infested with horn flies.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Serum constituent profiles of beef heifers infested with horn flies (Diptera: Muscidae). 783 15

The mixed-models procedure (MMP) was used to analyze pooled data sets from 12 independent studies conducted during the last 13 yr at nine locations in seven states to provide combined estimates of daily gains by beef steers (Bos taurus) grazing tall fescue (Festuca arundinacea Schreb.) pastures free of (E-) or infested (E+) at different levels with the endophytic fungus Acremonium coenophialum. Treatments included low-infestation (< or = 5% E+), moderate-infestation (> or = 20 to < or = 35% E+), and high-infestation (> or = 50 to < or = 97% E+) tall fescue pastures, and, in tall fescue-clover (Trifolium spp.) mixtures, pastures at the same E+ levels with approximately 25 and 10% clover in spring and summer stands, respectively. Spring, summer, and combined spring+summer data were analyzed separately. The MMP permitted estimation of the fixed effects of treatments over a broad inference space of future years and different tall fescue pastures over a wide geographic range; detected relationships that had not been apparent in the individual studies, such as the interactions between clover presence and E+ infestation levels; and provided a more coherent body of information than did the results obtained from each discrete study. Logistical and financial constraints that force undesirable compromises in the conduct of future grazing and other expensive or time-consuming research may be avoided by using MMP within the context of cooperative projects.
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PMID:Combined analysis of tall fescue steer grazing studies in the Eastern United States. 834 22

Lactating Sanga cows of the Mashona breed from Zimbabwe, receiving either a low or high level of nutritional supplement, were exposed to two levels of infestation of adults of the brown ear-tick, Rhipicephalus appendiculatus in the highveld of Zimbabwe. The effect of the ticks on the milk yield was measured over an 11-week period during the rainy season from January to April 1986. A technique in which calves were weighed before and after suckling was used to estimate milk yield. There were significant treatment effects of ticks (P < 0.05) on milk production but no significant differences in liveweight gain between calves from tick-free and tick-infested dams. The loss in milk production was poorly related to the number of female ticks that engorged, being 9 g (SEM 4) per tick. A Friesian x Hereford (Bos taurus) reference group of cattle carried 50% more ticks than the Mashona cows, illustrating a difference in resistance between the breeds. Thirteen screw-worm (Chrysomya bezziana) strikes were recorded amongst the thirty-two Mashona cows compared with twenty-one amongst the ten Friesian x Hereford animals between January and the end of March.
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PMID:The effects of the brown ear-tick, Rhipicephalus appendiculatus, on milk production of Sanga cattle. 922 44


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