Factors explaining the incidence of breech strike in a Mediterranean environment in unmulesed and uncrutched Merino sheep

Factors responsible for an increase in breech strike were investigated in an unmulesed Merino flock in a Mediterranean environment that were not crutched in 4 years but were crutched in the subsequent 2 years. No chemical preventative treatments such as dipping or jetting were applied in order to assess the susceptibility of the different progeny groups. The number of breech strikes for each animal was recorded from birth to hogget shearing at 17 months of age. Production traits were measured and a large number of visual wool and body conformational traits were subjectively scored to determine whether they contribute to variation in breech strike. Large differences (P < 0.01) in the incidence of breech strike were found between years. A significant interaction (P < 0.05) was found between year of birth and sex for breech strike to weaning, as rams had a higher strike rate than ewes in 1 year only. Across years ewes generally had a higher strike rate than rams. No consistent pattern in potential indicator traits could be found across years, as many traits each explain a small proportion of the variation in breech strike. Dags and skin wrinkle in the tail and breech area contributed most to the variation in breech strike. In uncrutched sheep, dags scored at yearling age for rams, and before hogget shearing for ewes, explained 16% and 10% of the variation in breech strike, respectively, whereas tail wrinkle scored post-weaner shearing explained 21% of the variation in breech strike in both ewes and rams. In sheep that were crutched at yearling age, about 4 months before the normal fly season, tail wrinkle was the most important indicator trait of breech strike in rams, whereas dags at yearling and dags before hogget shearing were the most important indicator traits in ewes. This research confirms that dags and wrinkles are major predisposing factors to breech strike in a Mediterranean environment and that sheep with higher dag and wrinkle scores were consistently more likely to be struck. A large proportion of variation in the incidence of breech strike remains unexplained in uncrutched and unmulesed sheep.

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Identifying indicator traits for breech strike in Merino sheep in a Mediterranean environment

Animal Production Science ◽

10.1071/an12233 ◽

2014 ◽

Vol 54 (2) ◽

pp. 125 ◽

Cited By ~ 31

Author(s):

J. C. Greeff ◽

L. J. E. Karlsson ◽

A. C. Schlink

Keyword(s):

Genetic Correlations ◽

Production Traits ◽

Production Environment ◽

Mediterranean Environment ◽

Important Indicator ◽

Body Conformation ◽

Heritable Trait ◽

Potential Indicator ◽

Normal Production ◽

Indicator Traits

Data from 2833 unmulesed Merino lambs from 49 sires and 1535 dams that were born from 2005 to 2009, were used to identify indicator traits for breech strike in a Mediterranean environment. Sheep were managed in a normal production environment where no preventative treatments were applied to protect them from being struck by flies, but were immediately treated when found to be fly struck. Seventy-seven skin, body conformation, wool, disease and production traits that may contribute to breech strike and that could qualify as potential indicator traits were recorded on progeny at birth, weaning, post-weaning, yearling, spring and at pre- and post-hogget age at ~18 months of age. In all, 31% of ewes and 22% of rams were fly struck in the breech area between birth and hogget shearing. The heritability of and the phenotypic and genetic correlations between the potential indicator traits and breech strike were estimated. The results showed that breech strike is a heritable trait (h2 = 0.51 ± 0.10), and that the most important indicator traits for breech strike were dags, scored at any time, especially at hogget age (rg = 0.81 ± 0.15), spring (rg = 0.77 ± 0.13) or at weaning (rg = 0.64 ± 0.00), urine stain scored at weaning (rg = 0.54 ± 0.13) and marking (rg = 0.51 ± 0.15), neck wrinkle at hogget age (rg = 0.46 ± 0.13) and breech cover (rg = 0.32 ± 0.15) scored at post-weaning shearing. These traits could be used to select indirectly for breech strike resistance in a Mediterranean environment.

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Genetic evaluation of production traits between and within flocks of Merino sheep. I. Hogget fleece weights, body weight and wool quality

Australian Journal of Agricultural Research ◽

10.1071/ar9890433 ◽

1989 ◽

Vol 40 (2) ◽

pp. 433 ◽

Cited By ~ 22

Author(s):

SI Mortimer ◽

KD Atkins

Keyword(s):

Body Weight ◽

Environmental Effects ◽

Genetic Variance ◽

Research Centre ◽

Production Traits ◽

Merino Sheep ◽

Wool Production ◽

Phenotypic Correlations ◽

Genetic And Phenotypic Correlations ◽

Fleece Weight

Wool production traits were measured on Merino hogget ewes in an unselected multiple-bloodline flock over a 7-year period at Trangie Agricultural Research Centre, N.S.W. The traits measured were greasy fleece weight (GFW), skirted fleece weight (SKFW), yield (Y), clean fleece weight (CFW), fibre diameter (FD), body weight (BWT) and staple length (SL). These measurements were used to examine genetic differences between and within flocks of Merino sheep, and to estimate heritability of and genetic and phenotypic correlations among these traits. Significant strain, flock within strain and flock effects were present for all traits. Interactions between these effects and year were non-significant. Within-flock genetic variance was always larger than between-flock within strain genetic variance for each trait. The influence of environmental effects on these traits was also examined. The environmental effects of birth-rearing type, age at observation and age of dam together accounted for about 7-10% of the total within-flock variation in fleece weights and body weight.After adjusting for significant environmental effects, paternal half-sib heritability estimates were 0.29 �. 0.06 for GFW, 0.22 � 0.05 for SKFW, 0.35 � 0.05 for Y, 0.30 �0.06 for CFW, 0.48 �0.07 for FD, 0.34 �. 0.06 for BWT and 0.44 �0.07 for SL. Estimates for genetic and phenotypic correlations were in agreement with published estimates except for the genetic correlation between CFW and FD (0.40 �. 0.11), and the genetic correlations involving BWT, which were essentially zero. The implications of the results of this study for the genetic improvement of Merino sheep for wool production are discussed.

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Genetic studies of South Australian Merino sheep. 2. Environmental effects on wool and body traits at 15-16 months of age

Australian Journal of Agricultural Research ◽

10.1071/ar9810657 ◽

1981 ◽

Vol 32 (4) ◽

pp. 657 ◽

Cited By ~ 2

Author(s):

IP Gregory ◽

RW Ponzoni

Keyword(s):

Body Weight ◽

Surface Area ◽

Multiple Birth ◽

Production Traits ◽

Merino Sheep ◽

Main Production ◽

The Difference ◽

Fleece Weight ◽

Main Components ◽

Australian Merino

The effects of years, sex, type of birth (i.e. whether or not multiple birth) and age of dam on 26 wool and body traits of South Australian Merino sheep were estimated by least-squares analysis. Years and sex had highly significant effects on all traits. Of the main production traits, type of birth had a significant effect on body weight, greasy and clean fleece weight and total wool follicle number, while age of dam only had a significant effect on body weight and greasy fleece weight. The possible consequences of failing to correct body weight and greasy and clean fleece weights for type of birth and age of dam were considered and it was concluded that, although in some years correction of these traits may not be warranted, in other years correction may be necessary to prevent selection against fecundity and an increase in the generation interval. The main components contributing to the 6.0 % difference between fleece weights of singles and twins were surface area, total follicle number and wrinkle score. The difference between fleece weights of animals from older ewes and animals from maidens was only 1.5 %; surface area was the main contributor to this deviation.

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Genetic and phenotypic parameters for reproduction, production and bodyweight traits in Australian fine-wool Merino sheep

Animal Production Science ◽

10.1071/an15738 ◽

2018 ◽

Vol 58 (2) ◽

pp. 207 ◽

Cited By ~ 3

Author(s):

S. Dominik ◽

A. A. Swan

Keyword(s):

Genetic Relationships ◽

Genetic Correlations ◽

Fibre Diameter ◽

Careful Consideration ◽

Production Traits ◽

Merino Sheep ◽

Wool Production ◽

Phenotypic Correlations ◽

Reproduction Traits ◽

Definition Of

The present study estimated phenotypic and genetic relationships between wool production, reproduction and bodyweight traits in Australian fine-wool Merino sheep. The data for the study originated from the CSIRO Fine Wool Project, Armidale, Australia. Data on wool characteristics, measured at ~10 and 22 months of age, bodyweight and several reproduction traits across consecutive lambing opportunities were analysed. The genetic correlations were moderately negative between fibre diameter measured as yearling and adult, and lamb survival (rg = –0.34 ± 0.15 and rg = –0.28 ± 0.14 respectively) and total number of lambs weaned (rg = –0.32 ± 0.21 and rg = –0.40 ± 0.21 respectively). The genetic correlations of yearling and adult greasy and clean fleece weights with number of lambs weaned and fecundity showed moderately to highly negative relationships and a moderately negative correlation with the number of fetuses at pregnancy scanning. Phenotypic correlations between reproduction and wool production traits were estimated to be zero, with the exception of bodyweight showing low to moderate positive phenotypic correlations with total number of lambs born and weaned. Genetic variances were generally low for the reproduction traits and resulted in low heritability estimates (from h2 = 0.03 ± 0.01 to h2 = 0.12 ± 0.13), with the exception of total number of lambs born (h2 = 0.25 ± 0.03). The study indicated that parameter estimation and trait definition of lifetime reproduction records require careful consideration and more work in this area is required.

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A Critical View on the Phenol Index as a Measure of Phenol Compounds Content in Waters. Application of a Biosensor

Ecological Chemistry and Engineering S ◽

10.2478/v10216-011-0028-5 ◽

2012 ◽

Vol 19 (3) ◽

pp. 383-391

Author(s):

Jolanta Kochana ◽

Juliusz Adamski ◽

Andrzej Parczewski

Keyword(s):

Spectrophotometric Method ◽

Significant Interaction ◽

Factorial Experiment ◽

Amperometric Biosensor ◽

Important Indicator ◽

Phenol Compounds ◽

Critical View ◽

Phenol Index ◽

Water Purity ◽

Biosensor Response

A Critical View on the Phenol Index as a Measure of Phenol Compounds Content in Waters. Application of a BiosensorPhenol index is considered as an important indicator of water purity and quality. Usually phenol index is determined by a spectrophotometric method the calibration being based on phenol standards. Unfortunately, the absorptivities of different phenols compounds differ from each other. This leads to significant uncertainty concerning content of phenols in water. It is shown that the same shortage of the phenol index appears also if it is determined using an amperometric biosensor based on tyrosinase. The sensitivity of the biosensor response to four phenol compounds: phenol, catechol, 3-cresol and 4-chlorophenol was examined, as well as possible interactions between phenols, according to 24factorial experiment. It was proved that individual phenols affect phenol index independently from each other,ieno significant interaction between phenols was detected. However, sensitivity of the biosensor to different phenols is not the same. Relationship between phenol index and concentrations of phenols in water is discussed.

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Are breech strike, dags and breech wrinkle genetically the same trait in crutched, uncrutched and mulesed Merino sheep?

Animal Production Science ◽

10.1071/an18461 ◽

2019 ◽

Vol 59 (10) ◽

pp. 1777

Author(s):

J. C. Greeff ◽

L. J. E. Karlsson ◽

A. C. Schlink

Keyword(s):

Genetic Correlation ◽

Standard Error ◽

Lower Risk ◽

Genetic Correlations ◽

High Standard ◽

Breeding Value ◽

Strongly Correlated ◽

Merino Sheep ◽

Skin Wrinkles ◽

Indicator Traits

Breech strike is caused by the infestation of maggots from Lucilia cuprina on the skin of susceptible sheep. Crutching and mulesing modify the potential expression of breech strike, because crutched and mulesed sheep have a lower risk of being struck than uncrutched sheep. The inheritance of and genetic correlations among breech strike from birth to hogget shearing, and dags (breech soiling) and skin wrinkles scored at yearling age were estimated in unmulesed and crutched, unmulesed and uncrutched, and in mulesed and uncrutched Merino sheep to determine whether these traits were genetically the same under these three husbandry systems. The heritability estimates of breech strike in uncrutched, crutched and mulesed sheep were very similar (0.11 ± 0.02, 0.09 ± 0.02 and 0.08 ± 0.05 respectively). Breech strike in uncrutched sheep is genetically strongly correlated with breech strike in crutched sheep (0.80 ± 0.16). The genetic correlation between breech strike in uncrutched and in mulesed sheep was high (0.98 ± 0.40), but the high standard error makes this estimate unreliable. Dags and wrinkles are genetically moderately to strongly correlated with breech strike, which confirms that they are indicator traits for breech strike. Dags in uncrutched sheep was genetically strongly correlated with dags in mulesed sheep (0.84 ± 0.11). Breech wrinkle in uncrutched and crutched sheep, and tail wrinkle in mulesed sheep were not genetically strongly correlated with each other, as the correlations varied between zero and 0.48 (±0.18). The key outcome from this study indicates that all breech strike, wrinkle and dag data in mulesed, crutched or uncrutched flocks may be used in future to estimate a breeding value directly for breech strike.

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Comparison of estimates of repeatability and heritability for some production traits in Merino rams and ewes. 2. Heritability

Australian Journal of Agricultural Research ◽

10.1071/ar9600604 ◽

1960 ◽

Vol 11 (4) ◽

pp. 604 ◽

Cited By ~ 13

Author(s):

SSY Young ◽

Turner H Newton ◽

CHS Dolling

Keyword(s):

Body Weight ◽

Population Density ◽

Sex Difference ◽

Fibre Diameter ◽

Production Traits ◽

Merino Sheep ◽

Lower Figure ◽

Selection Of ◽

Australian Merino ◽

Staple Length

Heritability estimates were calculated for 10 traits in rams and ewes of a medium-woolled strain of Australian Merino sheep. The traits were greasy wool weight, clean scoured yield, clean wool weight, body weight, wrinkle score, face cover score, fibre population density, fibre diameter, staple length, and crimps per inch. Estimates were made by dam-offspring correlations, measurement on the dams being at 15-16 months, on daughters at 15-16 months, and on sons at both 10-12 and 15-16 months. All estimates for both sexes lay between 0.3 and 0.6, except for fibre population density (0.24) and fibre diameter (0.12) in rams at 15-16 months and for clean wool weight (0.29) and face cover score (0.29) in rams at 10-12 months. The only significant sex difference lay in the lower figure for fibre diameter in rams at 15-16 months, but this is of doubtful importance as the corresponding figure for rams at 10-12 months (0.37) did not differ significantly from the ewe figure. All traits may be considered highly heritable, and the high values for the yearling rams indicate that consideration might be given to the selection of rams for production traits at an earlier age than the traditional one of 18 months or older.

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Genetic evaluation of production traits between and within flocks of Merino sheep. II. Component traits of the Hogget fleece

Australian Journal of Agricultural Research ◽

10.1071/ar9931523 ◽

1993 ◽

Vol 44 (7) ◽

pp. 1523 ◽

Cited By ~ 17

Author(s):

SI Mortimer ◽

KD Atkins

Keyword(s):

Agricultural Research ◽

Genetic Correlations ◽

Fibre Diameter ◽

Matter Content ◽

Research Centre ◽

Production Traits ◽

Merino Sheep ◽

Phenotypic Correlations ◽

Genetic And Phenotypic Correlations ◽

Fleece Weight

Components of the fleece and wool quality traits were measured or assessed on Merino hogget ewes in an unselected multiple-bloodline flock over a 7-year period at Trangie Agricultural Research Centre, N.S.W. The traits recorded were face cover score (FC), leg cover score (LC), neck fold score (NF), body fold score (BF), wax content (W), suint content (S), vegetable matter content (VM), dust penetration (D), follicle density (N) and follicle ratio (RA). Genetic differences within and between flocks of Merino sheep were examined for the traits, and estimates of heritability and within-flock genetic and phenotypic correlations and between-flock genetic correlations among the traits were obtained. Genetic and phenotypic correlations were also estimated between these traits and the major wool production traits: greasy fleece weight (GFW), clean fleece weight (CFW), fibre diameter (FD), body weight (BWT) and staple length (SL). Significant strain. flock within strain and flock effects were wresent for all traits. The influence of environmental effects (birth-rearing type, age at measurement and age of dam) on the traits was estimated, with the birth-rearing type being significant and the largest effect for most traits. Paternal half-sib heritability estimates were 0.44� 0.06 for FC, 0.35� 0.06 for LC, 0.24�0.05 for NF, 0.23�0.05 for BF, 0.38�0.07 for W, 0.42�0.07 for S, 0.06�0.04 for VM, 0.22�0.06 for D, 0.20� 0.07 for N and 0.21�0.07 for RA. Estimates of within-flock phenotypic and genetic correlations were in broad agreement with available published estimates. The implications of the results for Merino breeding programs are discussed.

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COMPARISONS OF CROSSBRED CALVES BY SOUTH DEVON, MAINE- ANJOU AND SIMMENTAL SIRES FOR SOME BEEF PRODUCTION TRAITS

Canadian Journal of Animal Science ◽

10.4141/cjas74-029 ◽

1974 ◽

Vol 54 (2) ◽

pp. 197-203 ◽

Cited By ~ 2

Author(s):

J. A. NEWMAN ◽

G. M. WEISS ◽

B. SCHRADER

Keyword(s):

Birth Weight ◽

Significant Interaction ◽

Statistical Significance ◽

Average Daily Gain ◽

Carcass Weight ◽

Production Traits ◽

Marbling Score ◽

Weaning Weight ◽

Slaughter Age ◽

Daily Gain

Breed of sire comparisons are made amongst calves born to commercial Hereford cows and sired by bulls of the South Devon (SD, 10 bulls used), Maine-Anjou (MA, two bulls used) and Simmental (SIM, eight bulls used) breeds. Numbers of observations ranged from 239 bulls and 224 heifers for "ease of birth" to 98 bulls for carcass traits. The feedlot test period was 91 days and three feedlot treatments were imposed. Slaughter criteria were subjective and "breed-of-sire" differences in slaughter age and carcass weight were not statistically significant (P > 0.05). Differences amongst breed-of-sire means attained statistical significance for "birth weight" (MA > SIM > SD; P < 0.001), weaning weight of males (MA > SIM > SD; P < 0.001), "on-test" weight (MA > SIM > SD; P < 0.001), average daily gain on test (MA > SIM > SD; P < 0.001) average fat depth/100 kg carcass weight (SD > MA = SIM, P < 0.05), trimmed, de-boned, defatted primal cuts per day of age (MA > SIM > SD; P < 0.01), meat marbling score (SD more marbled than SIM more marbled than MA; P <.05). A significant interaction existed between breed of sire and feeding group for average daily gain on test (P < 0.01) and cutability (P < 0.025). Breed-of-sire differences did not attain statistical significance for weaning weight of female calves, loin area/100 kg carcass weight, cut-ability, or meat color score.

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