The performance of Brahman-Shorthorn and Sahiwal-Shorthorn beef cattle in the dry tropics of northern Queensland. 5. Scrotal circumference, temperament, ectoparasite resistance, and the genetics of growth and other traits in bulls

1996 ◽  
Vol 36 (1) ◽  
pp. 9 ◽  
Author(s):  
G Fordyce ◽  
CJ Howitt ◽  
RG Holroyd ◽  
PK O'Rourke ◽  
KW Entwistle
Keyword(s):  
Growth Rates ◽  
Bos Indicus ◽  
Genetic Correlations ◽  
Boophilus Microplus ◽  
Flight Distance ◽  
Cattle Tick ◽  
Scrotal Circumference ◽  
Dry Tropics ◽  
Significant Relationships ◽  
Tick Resistance

The genetics of growth to 24 months, scrotal circumference (SC) at 24 months and temperaments at 6, 12 and 18 months in 7 year groups of F2 et seq., 1/2 Brahman, 1/2 Sahiwal, 3/4 Brahman and 3/4 Sahiwal bulls were investigated in the dry tropics of northern Queensland. Cattle tick (Boophilus microplus) and buffalo fly (Haematobia irritans exigua) resistance were also assessed at 24 months. Scrotal circumference at 24 months was highest in 1/2 Sahiwal crosses (28 cm v. 26-27 cm; P<0.05) with pronounced variation between years (24-31 cm; P<0.05). Temperaments (TEM score; flight distance) were generally poorest in 3/4 Sahiwal crosses (P<0.05). Bulls of 1/2 Bos indicus content were twice as susceptible as 3/4 crosses to tick infestations (P<0.05). There were no genotype differences in natural buffalo fly infestations. Temperaments, tick resistance and buffalo fly resistance all had no consistent significant relationships with either each other or with weights or growth rates to 24 months. Paternal half-sib estimates of heritabilities across all genotypes were generally moderate for weight (0.20-0.36), growth rates (0.08-0.46), and SC (0.32), low for TEM score (0.08-0.14), and high for flight distance (0.32-0.70). The genetic correlations (rG) between growth rates in both dry and wet seasons after weaning were high (>0.9); however, the rG of weaning weight with postweaning seasonal growth rates to 24 months were consistently negative (-0.09 to -0.71; P>0.05). The rG of SC with post-weaning growth rates were negative (-0.4 to -0.8). The rG of SC with weights up to 18 months were not significantly different to zero, but tended to be negative with weight at 24 months.

Host resistance to cattle tick (Boophilus microplus) in Brahman (Bos indicus) cattle. III.* Growth on previously unexposed animals

1978 ◽  
Vol 29 (2) ◽  
pp. 401 ◽  
Author(s):  
BM Wagland
Keyword(s):  
Skin Temperature ◽  
Growth Rates ◽  
Host Resistance ◽  
Bos Indicus ◽  
Growth Curves ◽  
Boophilus Microplus ◽  
Cattle Tick ◽  
Brahman Cattle ◽  
Length Measurements ◽  
Surface Skin Temperature

Length measurements were used to compare the growth of the parasitic stages of Boophilus microplus on previously unexposed Brahman (Bos indicus) and Shorthorn (B. taurus) cattle. Growth curves based on the length measurements were constructed. Growth was slower on Brahmans than on Shorthorns during the first 24 hr of larval and nymphal instars. After the first 24 hr, the growth rates of larvae, and of nymphs, during feeding to engorgement were the same on the rump and belly regions of both species of cattle. Larvae and nymphs engorged more slowly on the brisket than they did on the rump and belly regions of the Brahmans. The surface skin temperature was lower on the brisket of the Brahmans. On the basis of change in the length of the tick during development on Brahmans, 16 age categories were established, so that the length of the tick may be used to estimate the ages of ticks in populations on Brahman cattle. Age categories were also defined for ticks which had been processed in formalin and hot alkali. __________________ *Part II, Aust. J. Agric. Res., 29: 395 (1978).

Ecology of the cattle tick (Boophilus microplus) in subtropical Australia. I. Introduction and free-living stages

1988 ◽  
Vol 39 (2) ◽  
pp. 285 ◽  
Author(s):  
RW Sutherst ◽  
ID Sutherland ◽  
AS Bourne ◽  
GF Maywald ◽  
DA Stegeman
Keyword(s):  
Host Resistance ◽  
Bos Indicus ◽  
Boophilus Microplus ◽  
Cattle Tick ◽  
Climatic Effects ◽  
Free Living ◽  
Tick Reproduction ◽  
The Relationship ◽  
Tick Resistance ◽  
Subtropical Australia

An experiment is described which compared the fluctuations in the numbers of cattle tick, Boophilus miicroplus, that resulted from direct climatic effects or from changes in host resistance. Four herds of cattle, matched for tick resistance and with different Bos indicus (zebu) content, were grazed at each of two locations, one in central Queensland (23� S.) and one in southern Queensland (28� S.), from November 1977 to May 1982. Natural tick populations were counted regularly, and host resistance was measured using artificial infestations, either twice or six times a year. Concurrent exposures of engorged ticks in pastures were used to measure the success of the ticks in producing larvae and to partition mortality during development. Two later papers report other aspccts of the experiment. These include observations on the resistance of cattle to ticks and on the relationship between tick numbers on the cattle on one hand, and the availability of larvae on pasture and survival of parasitic stages on the other. Engorged ticks produced more larvae throughout the year in central Queensland, despite laying fewer eggs. The colder and longer winter in southern Queensland greatly reduced tick reproduction. Failure of engorged ticks to survive predation and find a favourable oviposition site, egg mortality and loss of larvae in the pasture accounted for most of the reduction in the potential number of larvae produced. Reduced oviposition was also important in wintcr.

Gene expression in the skin of Bos taurus and Bos indicus cattle infested with the cattle tick, Rhipicephalus (Boophilus) microplus

2008 ◽  
Vol 126 (1-2) ◽  
pp. 110-119 ◽  
Author(s):  
Emily K. Piper ◽  
Louise A. Jackson ◽  
Neil H. Bagnall ◽  
Kritaya K. Kongsuwan ◽  
Ala E. Lew ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Boophilus Microplus ◽  
Cattle Tick

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.

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.

Effect of cattle tick (Boophilus microplus) infestation on performance of Bos indicus cross cows and their progeny

1988 ◽  
Vol 28 (1) ◽  
pp. 1 ◽  
Author(s):  
RG Holroyd ◽  
PJ Dunster ◽  
PK O'Rourke
Keyword(s):  
Pregnancy Rate ◽  
Bos Indicus ◽  
Treated Group ◽  
Pregnancy Rates ◽  
Boophilus Microplus ◽  
Cattle Tick ◽  
First Year ◽  
The Third ◽  
Lactating Cows ◽  
Tick Counts

The effects of cattle tick infestations on liveweight and fertility of Droughtmaster (1/2 Bos indicus) cows and on calf weaning weights were determined over 3 years. Tick populations on the control (non-dipped) group of cattle fluctuated, with mean annual tick counts/side being 9.5, 8.9 and 13.6 for years 1, 2 and 3 respectively, while the treated group of cattle, which were dipped every 21 days, were free of ticks. Tick counts were not related to fertility or liveweight change in pregnant-lactating cows or to calf growtb or weaning weights. Treatment for ticks significantly (P<0.05) affected liveweight change in pregnant-lactating cows on only a few occasions, and annual liveweight changes were not significantly influenced by treatment. When lactating cow pregnancy rates were low (< 30% for control cows), treatment for ticks increased the pregnancy rate by about 100% in 2 of the 3 years, these differences being significant only in the last year. Calves in the treated group were born significantly earlier in the first year and had significantly lighter birth weights in the third year. Treated calves grew faster to weaning and had higher weaning weights (mean difference 17.9 kg) than control calves but differences were significant in the first and third years only.

Host resistance to cattle tick (Boophilus microplus) in Brahman (Bos indicus) cattle. II.* The dynamics of resistance in previously unexposed and exposed cattle

1978 ◽  
Vol 29 (2) ◽  
pp. 395 ◽  
Author(s):  
BM Wagland
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Host Resistance ◽  
Initial Period ◽  
Bos Indicus ◽  
Boophilus Microplus ◽  
Phase Iii ◽  
Cattle Tick ◽  
Development Of Resistance

The dynamics of host resistance to Boophilus microplus was investigated in previously unexposed and exposed Brahmans, and in previously unexposed Shorthorn cattle. The animals were infested each day with 1000 larvae, and the development of resistance was monitored by counting the number of female ticks which engorged. The previously unexposed cattle showed an initial period of susceptibility (phase I) which was followed by a period in which most animals developed degrees of resistance (phase II), and which stabilized in some animals (phase III). The duration of phase I was shorter in Brahmans, and they developed higher levels of resistance (phase III). In contrast, previously cxposed Brahmans manifested phase III levels of resistance immediately on infestation. The results provide further evidence that resistance to B. microplus in Brahmans, as well as in European breeds, is acquired rather than innate. __________________ *Part I, Aust. J. Agric. Res., 26: 1073 (1975).

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.

Genetic correlations between body weight, scrotal circumference and visual evaluation scores in Bos indicus cattle

2018 ◽  
Vol 89 (9) ◽  
pp. 1223-1229 ◽  
Author(s):  
Luíza R. A. Abreu ◽  
Paulo G. M. A. Martins ◽  
Lúcio F. M. Mota ◽  
Talita A. Ferreira ◽  
Virgínia M. P. Ribeiro ◽  
...  
Keyword(s):  
Body Weight ◽  
Bos Indicus ◽  
Genetic Correlations ◽  
Visual Evaluation ◽  
Scrotal Circumference ◽  
Evaluation Scores
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