Resistance to the cattle tick, Boophilus microplus in a herd of Australian Illawarra Shorthorn cattle: Its assessment and heritability

1970 ◽  
Vol 21 (1) ◽  
pp. 163 ◽  
Author(s):  
RH Wharton ◽  
KBW Utech ◽  
HG Turner
Keyword(s):  
Reference Value ◽  
Mature Female ◽  
Boophilus Microplus ◽  
Supplementary Information ◽  
Cattle Tick ◽  
The Mean ◽  
Tick Counts ◽  
The Right ◽  
High Level ◽  
Tick Resistance

An Australian Illawarra Shorthorn herd of 24 cows was mated in three consecutive years with an AIS bull. The cows and their progeny were rated for tick resistance at frequent intervals from August 1959 to December 1965 by counting the numbers of semiengorged female ticks on the right side. The mean of log counts for all counts on a particular animal was adopted as the reference value for its degree of susceptibility. The ranking of cattle generally showed a high level of consistency with mean repeatability of counts (r = 0.47, P < 0.01). Discrimination between animals was more reliable (P < 0.01) in summer (r = 0.52) than in winter (r = 0.27). The repeatability of tick counts increased with mean count, from r = 0.27 when the mean count was 3 to r = 0.67 when it was 100. The reliability of counts on the cows decreased with age and with lactation. Supplementary information on a larger herd showed no effect of pregnancy on mean count or on discrimination between susceptible and resistant animals, but showed that there was a partial breakdown of resistance during lactation. In calves infested naturally, no effects of age or sex on tick counts or their repeatability were detected, though male calves yielded significantly larger numbers of ticks than females when infested artificially. The mean yield of mature female ticks on the cows following two artificial infestations with known numbers of larvae ranged from 0.2 to 27.4% of the potential. Natural and artificial assessments of susceptibility were closely correlated. The rank of the bull was similar to that of the more resistant cows. Mean estimates of the heritability of tick resistance based on single counts were 39 % from dam-calf correlations and 49 % from full-sib correlations. Estimates based on summer counts only were 42 and 64% respectively. These results provide strong encouragement for selecting for tick resistance.

Heritability estimates from correlations in intra-sire data. Appendix I. from - Resistance to the cattle tick, Boophilus microplus in a herd of Australian Illawarra Shorthorn cattle: Its assessment and heritability

1970 ◽  
Vol 21 (1) ◽  
pp. 181
Author(s):  
HG Turner
Keyword(s):  
Reference Value ◽  
Mature Female ◽  
Boophilus Microplus ◽  
Supplementary Information ◽  
Cattle Tick ◽  
The Mean ◽  
Tick Counts ◽  
The Right ◽  
High Level ◽  
Tick Resistance

An Australian Illawarra Shorthorn herd of 24 cows was mated in three consecutive years with an AIS bull. The cows and their progeny were rated for tick resistance at frequent intervals from August 1959 to December 1965 by counting the numbers of semiengorged female ticks on the right side. The mean of log counts for all counts on a particular animal was adopted as the reference value for its degree of susceptibility. The ranking of cattle generally showed a high level of consistency with mean repeatability of counts (r = 0.47, P < 0.01). Discrimination between animals was more reliable (P < 0.01) in summer (r = 0.52) than in winter (r = 0.27). The repeatability of tick counts increased with mean count, from r = 0.27 when the mean count was 3 to r = 0.67 when it was 100. The reliability of counts on the cows decreased with age and with lactation. Supplementary information on a larger herd showed no effect of pregnancy on mean count or on discrimination between susceptible and resistant animals, but showed that there was a partial breakdown of resistance during lactation. In calves infested naturally, no effects of age or sex on tick counts or their repeatability were detected, though male calves yielded significantly larger numbers of ticks than females when infested artificially. The mean yield of mature female ticks on the cows following two artificial infestations with known numbers of larvae ranged from 0.2 to 27.4% of the potential. Natural and artificial assessments of susceptibility were closely correlated. The rank of the bull was similar to that of the more resistant cows. Mean estimates of the heritability of tick resistance based on single counts were 39 % from dam-calf correlations and 49 % from full-sib correlations. Estimates based on summer counts only were 42 and 64% respectively. These results provide strong encouragement for selecting for tick resistance.

Long-term population studies on the cattle tick (Boophilus microplus) on untreated cattle selected for different levels of tick resistance

1979 ◽  
Vol 30 (2) ◽  
pp. 353 ◽  
Author(s):  
RW Sutherst ◽  
RH Wharton ◽  
IM Cook ◽  
ID Sutherland ◽  
AS Bourne
Keyword(s):  
Census Data ◽  
Seasonal Pattern ◽  
Boophilus Microplus ◽  
Cattle Tick ◽  
Tick Population ◽  
Population Sizes ◽  
The Mean ◽  
Highly Correlated ◽  
Tick Counts ◽  
Tick Resistance

Census data were collected at weekly intervals on tick populations on untreated cattle over a period of 6 years in central Queensland, near Rockhampton. Hereford x Shorthorn (British; HS) heifers and two herds of Africander (Zebu) x [Hereford and Shorthorn] (AX) heifers, one with animals of high resistance (AXH) and the other of medium (AXM) tick resistance, were grazed in separate paddocks. A herd of AX steers was added to the trial when the heifers commenced calving in 1972–73. Data were collected from the heifers for three years prior to their first calving and then for a further three years whilst they were breeding. There were large differences between the numbers of ticks in different years and a consistent seasonal pattern, the numbers being lowest from July to September and highest in the April to June quarter. The AXH herd had fewest ticks for most of the experiment, but after the first year there was little difference between the infestations on the AXM and HS herds. The resistance of all herds, measured by artificial infestations with larvae, increased during the first 3 years but declined after the cattle began breeding, and fluctuated from year to year. The resistance of some heifers did not stabilize until the animals were more than a year old, and that of some animals drifted up or down over long periods. The loss of resistance of a small proportion of the cattle in the AXH herd was responsible for the advantage of that herd being substantially reduced. Both the ranking for resistance of animals and the mean resistance of the herds, assessed with artificial infestations, agreed with the rankings and tick population sizes observed from tick counts on the cattle in the field. Changes in the mean resistance of the herds in spring in different years were highly correlated with concurrent field infestations, which suggests that changes in host resistance have important effects on tick populations. Tick counts on the calves up to weaning showed no correlation with concurrent counts on their dams, but the ranking of the counts on the calves was consistent over the 6 month period.

Chemical control of the cattle tick Boophilus microplus (Can.)

1965 ◽  
Vol 55 (4) ◽  
pp. 617-635 ◽  
Author(s):  
W. J. Roulston ◽  
J. T. Wilson
Keyword(s):  
Organophosphorus Compounds ◽  
Boophilus Microplus ◽  
Reproductive Capacity ◽  
Cattle Tick ◽  
Clear Cut ◽  
Large Numbers ◽  
Hair Samples ◽  
Biological Tests ◽  
The Mean ◽  
High Level

The effectiveness of ten acaricides against Boophilus microplus (Can.) on cattle in southern Queensland, Australia, was investigated in 1960–63. Of infested cattle dipped in or sprayed with each acaricide, some were kept in stalls so that observations on ticks that survived treatment could be made, and others were grazed in tick-infested pastures in order to find the period of protection against reinvasion by larvae. Untreated cattle were also kept in the stalls to indicate the numbers of ticks occurring in the absence of treatment. The reproductive capacity, in terms of eggs and larvae produced, of ticks surviving treatment was compared with that of untreated ticks, and, for aldrin, dieldrin and the last four compounds mentioned below, the protective period in the field was compared with deposits of acaricide on the hair of the cattle as indicated by chemical and biological tests. For the last four acaricides, the effect on toxicity of artificially fouling the dip fluid was investigated, and also the relative toxicity of clean and artificially fouled fluids to ticks dipped in them under laboratory conditions.The acaricides tested, and (in brackets) the concentrations used, were aldrin (0·05 & 0·1%), dieldrin (0·1%), carbaryl (0·2%), Boots' ED 12308 (0·2%), ethion (0·1%), Ciodrin (0·1%), coumaphos (0·02%), diazinon (0·05%), carbophenothion (0·086%) and dioxathion (0·075%). All were emulsion formulations except carbaryl and diazinon, which were used in wettable-powder form.Daily collections of engorged adult ticks that fell from the stalled cattle provided clear-cut, though not quantitative, assessments of the effects of the acaricides. All the compounds tested gave a very high level of control, the only exception being the lower concentration of aldrin, and the reproductive capacity of ticks that survived treatment was negligible. With some of the acaricides, large numbers of surviving ticks fell in the first day or two after treatment, and some laid eggs; but the viability of the latter was invariably low. These observations emphasise the need to consider the reproductive capacity as well as the direct kill of parasitic ticks when assessing the value of acaricides. At the concentrations tested, nearly all the compounds allowed a few ticks to survive that were in the engorged-nymph stage at the time of treatment; these dropped off the cattle from the tenth day onwards and laid viable eggs.The mean protective periods of the chlorinated hydrocarbons and organophosphorus compounds ranged from three to six days, but on individual animals periods from three to eight days were recorded. Amongst the carbamates, a mean protective period of seven days was recorded for carbaryl in summer, whereas the mean protective period of RD12308 in winter, when such periods are longer, was 12 days. In come cases, protection appeared to continue when deposits of the original acaricide could no longer be detected on hair samples, and reasons for this are discussed.The influence of various factors, other than concentration, on the effectiveness of acaricidal fluids and on the results of tests was examined. Chemical and biological tests of hair samples showed that the acaricides persisted longer on stalled than on pastured cattle. Formulations affected the amount of toxicant deposited on the hair, and there was an indication that fouling of the dip fluid with soil and dung may, under certain circumstances, increase the amount of toxicant deposited.

A comparison of cattle tick control by pasture spelling, planned dipping, and tick-resistant cattle

1969 ◽  
Vol 20 (4) ◽  
pp. 783 ◽  
Author(s):  
RH Wharton ◽  
KLS Harley ◽  
PR Wilkinson ◽  
KB Utech ◽  
BM Kelley
Keyword(s):  
Mature Female ◽  
Tick Control ◽  
Boophilus Microplus ◽  
Cattle Tick ◽  
Control Methods ◽  
Artificial Infestation ◽  
Wet Tropics ◽  
Cattle Herds ◽  
The Right ◽  
Tick Burden

Control of Boophilus microplus by pasture spelling, planned dipping, and simulated "conventional" control methods was compared in duplicate herds of British cattle, and by simulated "conventional" control methods in duplicate herds of Zebu x British and a single mixed herd of Zebu x British and British cattle. Herds under conventional control were treated with an acaricide (dipped) when the count of "standard" ticks (5 mm or more in length) on the right side averaged 20 or more per animal. Herds under pasture spelling grazed alternately in two adjacent paddocks; the summer spelling period was 3½ months, followed by spelling periods of 4½ months, and cattle were dipped on transfer between paddocks. Herds under planned dipping were dipped at 21-day intervals until few larvae remained on the pasture, this treatment being repeated when the count of standard ticks averaged more than 20 per animal. Observations over 2 years confirmed the results of an earlier experiment which showed that pasture spelling and planned dipping resulted in increased efficiency of tick control. Compared with British herds under conventional control which required dipping on 19 and 20 occasions, herds managed by pasture spelling were dipped only on seven occasions and showed a mean reduction of 81% in tick burden. Herds subjected to planned dipping required 18 treatments but the tick burden was reduced by 83%. The two Zebu x British herds required dipping on four and 10 occasions and showed a mean reduction in tick burden of 39% compared with British herds under conventional control. There was little improvement in tick control in the mixed herd of Zebu x British and British cattle. Assessment of the tick resistance status of the Zebu x British cattle by artificial infestation with known numbers of larvae showed that the survival to mature female ticks was 1.3 and 1.8% for the herds requiring four and 10 acaricidal treatments respectively in the wet tropics. In a similar assessment of the "resistant" Australian lllawarra Shorthorn (AIS) cattle herds which required one treatment or none over a tick season in southern Queensland (Wilkinson 1962) the survival was 4.4 and 5.2% respectively. The mean survival of female ticks to maturity on individual Zebu x British cattle was 1.4% (range 0.01–6.6%) compared with 8.1 % (0.2–27.4%%) for AIS cattle.

scholarly journals Baculoviral Expression of Presumptive OP-Resistance Mutations in BmAChE1 of Rhipicephalus (Boophilus) microplus (Ixodida: Ixodidae) and Biochemical Resistance to OP Inhibition

2019 ◽  
Vol 56 (5) ◽  
pp. 1318-1323
Author(s):  
Kevin B Temeyer ◽  
Kristie G Schlechte ◽  
William P McDonough
Keyword(s):  
United States ◽  
The United States ◽  
Boophilus Microplus ◽  
Cattle Tick ◽  
Resistance Mutations ◽  
Bovine Babesiosis ◽  
Gene Encoding ◽  
Southern Cattle Tick ◽  
High Level ◽  
Tick Resistance

Abstract The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini), transmits bovine babesiosis and anaplasmosis, and is endemic to Mexico, Latin and South America. Rhipicephalus (B.) microplus infestations within the United States are a continuing threat to U.S. cattle producers. An importation barrier between Texas and Mexico keeps the ticks from re-entering the United States. All cattle imported into the United States are dipped in an organophosphate (OP) acaricide and hand inspected for presence of ticks. Tick resistance has developed to most available acaricides, including coumaphos, the OP used in the cattle dip vats. OP-resistance can result from one or more mutations in the gene encoding the enzyme, acetylcholinesterase (AChE), resulting in production of an altered AChE resistant to OP inhibition. Previous research reported a large number of BmAChE1 mutations associated with OP resistance. We report baculovirus expression of recombinant tick BmAChE1 (rBmAChE) enzymes containing a single resistance-associated mutation, to assess their contribution to OP inhibition resistance. Surprisingly, of the naturally occurring BmAChE1 resistance-associated mutations, only D188G resulted in markedly reduced sensitivity to OP-inhibition suggesting that OP-insensitivity in BmAChE1 may result from the D188G mutation, or may possibly result from multiple mutations, each contributing a small decrease in OP sensitivity. Furthermore, an OP-insensitivity mutation (G119S) found in mosquitoes was expressed in rBmAChE1, resulting in 500-2000-fold decreased sensitivity to OP inhibition. Recombinant BmAChE1 with the G119S mutation demonstrated the lack of any structural prohibition to broad and high-level OP-insensitivity, suggesting potential increases in tick OP-resistance that would threaten the U.S. importation barrier to ticks.

Resistance to Boophilus microplus (Canestrini) in different breeds of cattle

1978 ◽  
Vol 29 (4) ◽  
pp. 885 ◽  
Author(s):  
KBW Utech ◽  
RH Wharton ◽  
JD Kerr
Keyword(s):  
Beef Cattle ◽  
High Resistance ◽  
Bos Indicus ◽  
Boophilus Microplus ◽  
Supplementary Information ◽  
Cattle Tick ◽  
Tick Population ◽  
Frequency Distributions ◽  
Jersey Cattle ◽  
The Mean

Resistance to the cattle tick Boophilus microplus was assessed in heifer herds of various breeds of beef and dairy cattle in spring and summer in Queensland. All cattle had had tick experience before assessment. Resistance levels were determined as the percentage of larval ticks that failed to survive to maturity following infestations with c. 20,000 larvae. Bos indicus Brahman beef cattle were the most resistant (99%), followed by B. indicus × B. taurus (95–97%) and B. taurus British cattle (85%). In the dairy breeds, B. taurus Jersey cattle (98%) were more resistant than Guernsey (93%), Australian Illawarra Shorthorn (89%), and Friesian (85%), but not significantly different from B. indicus × B. taurus Australian Milking Zebu (96%). Cattle were classified as having high (> 98%), moderate (95–98%), low (90–95%), or very low (< 90%) resistance. The frequency distributions of resistance in B. indicus × B. taurus cattle showed that 80% had moderate to high resistance and that culling of 20% of the cattle would about halve the mean tick population. Of B. taurus cattle, 80% had low to very low resistance. Supplementary information on sibling bull herds showed that their resistance levels and frequency distributions of resistance were similar to those of the heifer herds.

DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

2019 ◽  
Author(s):  
Danilo Carmona ◽  
Pablo Jaque ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Reference Value ◽  
Basis Set ◽  
Basis Sets ◽  
Mean Deviation ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
The Mean ◽  
Experimental Values ◽  
High Level ◽  
Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

Host resistance to cattle tick (Boophilus microplus) in Brahman (Bos indicus) cattle. I. Responses of previously unexposed cattle to four infestations with 20,000 larvae

1975 ◽  
Vol 26 (6) ◽  
pp. 1073 ◽  
Author(s):  
BM Wagland
Keyword(s):  
Host Resistance ◽  
Bos Indicus ◽  
Boophilus Microplus ◽  
Cattle Tick ◽  
Brahman Cattle ◽  
The Mean

Four purebred Brahman and four beef Shorthorn cattle which had not previously been exposed to Boophilus microplus were infested four times with 20,000 B. microplus larvae. On first infestation, the yield of engorged female ticks on all animals was about 25% of the larvae applied. Aftcr three further infestations, the mean yield of engorged females on the Brahmans decreased to 7.5% whereas there was no decrease in the yield of ticks on the Shorthorns. On the Brahman cattle. development of larvae to engorged females took 1–2 days longer and the engorged females weighed less. However, there was no difference in the reproductive index of female ticks engorged on either Brahmans or Shorthorns. Increases in rectal temperatures occurred in all cattle 15–17 days after the first infestation and in some cattle on days 6–7 as well as on days 15–17 after reinfestation. It was concluded that resistance to B. microplus is an acquired phenomenon in Brahman cattle.

Selection of cattle for tick resistance, and the effect of herds of different susceptibility on Boophilus populations

1962 ◽  
Vol 13 (5) ◽  
pp. 974 ◽  
Author(s):  
PR Wilkinson
Keyword(s):  
Tick Infestation ◽  
Tick Control ◽  
Boophilus Microplus ◽  
Skin Thickness ◽  
Adult Females ◽  
Cattle Ticks ◽  
In Parenthesis ◽  
Tick Counts ◽  
Tick Resistance ◽  
Selection Of

Weekly counts of Boophilus microplus (Canestrini) on 30 Australian Illawarra Shorthorn heifers enabled the cattle to be ranked in order of tick infestation, with highly significant correlations between counts of two observers and between counts of one observer on different occasions. In May 1960, when the heifers were 1½–2 years old, 12 were selected as relatively tick-resistant and 12 as relatively tick-susceptible. Each of these groups was divided at random into herds of six, and the four herds were then allotted randomly to separate paddocks, each onequarter of the area previously grazed. A herd was sprayed with 0.5% DDT emulsion when its average count of ticks (adult females over 5 mm in length) on one side of the animals exceeded 40. During the ensuing tick season, from October 5, 1960, to June 7, 1961, the sums of average weekly tick counts, and the numbers of sprayings (in parenthesis) were: susceptible herds 4853 (5) and 5962 (6): resistant herds 718 (0) and 1073 (1). Counts of tick larvae on defined body areas showed that, in the summer after segregation, resistant herds carried fewer larvae than the susceptible herds, apparently because fewer mature ticks fell from the resistant cattle in the preceding spring and winter. As a consequence of this, counts of adult ticks were comparatively lower after than before segregation. There was little or no 'spring rise' of tick infestation on the resistant herds. There was no significant correlation between tick resistance and coat score, sweat gland dimensions, or total skin thickness, but a correlation of -0.53 with follicle depth was significant at the 1% level. There was no evidence of adaptation of cattle ticks to the resistant animals, either in the field experiment or in observations on stalled cattle. The experiment draws attention to the appreciable proportion of tick-resistant animals within the Australian Illawarra Shorthorn breed, which has largely been overlooked in past discussions on tick-resistant breeds of cattle. It also suggests a technique for estimating the improvement in tick control that may be obtained by a given degree of selection within any breed, for any given environment.

The inheritance of DDT-resistance in the cattle tick, Boophilus microplus

1962 ◽  
Vol 13 (5) ◽  
pp. 984 ◽  
Author(s):  
BF Stone
Keyword(s):  
Resistant Strain ◽  
Reference Strain ◽  
Boophilus Microplus ◽  
Autosomal Gene ◽  
Cattle Tick ◽  
Adult Females ◽  
Ddt Resistance ◽  
High Level ◽  
Multiresistant Strain

Adults of a DDT-resistant strain of the cattle tick from central Queensland were crossed with adults of a susceptible reference strain, by means of cardboard mating boxes glued to the skins of cattle. F1, backcross, and F2 larvae were tested for resistance to DDT by enclosure of larvae in filter paper packets impregnated with oil solutions of pp'-DDT. F1 and backcross engorged adult females were tested for resistance by injection with oil solutions of pp'-DDT. There was no evidence of departure from a 1 : 1 ratio in the backcrosses or from a 1 : 2 : 1 ratio in the F2, and there was little difference between the compositions of the F1 reciprocal crosses or among the backcrosses derived from them. Therefore DDT resistance in this strain was considered to be due to a single, incompletely recessive, autosomal gene. Engorged nymphs of the resistant strain moulted later in vitro than nymphs of the susceptible strain, and resistant engorged adult females detached from the host later than susceptible engorged adult females. After 13 generations of DDT-free culturing of a multiresistant strain, the percentage of homozygous DDT-resistant ticks in the strain had fallen from a high level to about 55%. This figure remained constant for a further 10 generations.

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