Carcass characteristics and meat quality of progeny of five Merino dam lines, crossed with Dormer and Suffolk sires

This study details the slaughter traits of lambs born from a terminal crossbreeding experiment that involved five Merino type dam lines crossed with Dormer and Suffolk sires. Dam lines included dual purpose types; South African Mutton Merino (SAMM), Dohne Merino, SAMM rams crossed to commercial Merino ewes (SAMM cross) and specialist Merino lines selected either for clean fleece weight (FW+) or for an increased fertility (Rep+). Data include between 228 and 483 individual records, depending on the trait. The unadjusted fat depth 25 mm from the midline at the 13th rib of lambs from dual-purpose ewes was between 22 and 32% greater than that of lambs from FW+ Merino ewes. Progeny from Rep+ Merino ewes showed a closer resemblance to the progeny of dual-purpose breeds than to those of FW+ Merino ewes in this instance. Adjustment for slaughter weight eliminated these differences. The initial pH of meat from progeny of FW+ Merino ewes was lower than that from progeny of dual-purpose ewes, and Rep+ Merino ewes. No differences in Warner-Bratzler shear values of the meat were found between the different crosses. Crossbred progeny of the Merino lines performed satisfactorily for all the traits considered, and will not be discriminated against in the market. No conclusive differences in favour of either sire breed were found. Keywords: Dohne Merino, meat quality, SA Mutton Merino, terminal crossbreeding South African Journal of Animal Science Vol. 38 (4) 2008: pp. 355-36

Production of five Merino type lines in a terminal crossbreeding system with Dormer or Suffolk sires

This study details the production performance of ewes and lambs that originated from a terminal crossbreeding experiment that involved five Merino type dam lines and two terminal crossbreeding sire lines from 1999 to 2002. Ewe lines were SA Mutton Merino (SAMM), SAMM rams crossed to Merino ewes (SAMM cross), Dohne Merino, as well as specialist Merino lines selected for clean fleece weight (FW+) and for an increased reproduction rate (Rep+). Dormer and Suffolk rams were used as sire breeds on these ewes. Data include 777 birth and 605 weaning records of lambs and 562 production year records of ewes. At birth the progeny of SAMM ewes were heavier than those of the other ewe lines, while FW+ ewes produced smaller lambs at birth than SAMM cross and Rep+ ewes. Lamb survival was not significantly affected by ewe line or sire breed. The progeny of the dual-purpose ewe lines (SAMM, SAMM cross and Dohne Merino) were heavier than those of Merino ewes (FW+ and Rep+) at weaning. No sire breed difference was found for birth or weaning weight. The joining weights of dual-purpose ewe lines were higher than those of Merinos. Although considerable variation was found between ewe lines in terms of lamb output (number or weight of lamb weaned per ewe joined), the only significant difference was for weight of lamb weaned between SAMM cross and FW+ Merino ewes. Means for weight of lamb weaned per joining (in kg) were 37.3 for SAMM ewes, 39.6 for SAMM cross ewes, 35.5 for Dohne Merino ewes, 28.9 for FW+ ewes and 34.6 for Rep+ ewes. No differences in ewe reproduction were found between ewes joined to Dormer or Suffolk rams. The clean wool production of SAMM ewes amounted to 46% of that recorded in FW+ ewes. Corresponding percentages were 68% for SAMM cross ewes, 74% for Dohne Merino ewes and 90% for Rep+ ewes. The wool of SAMM ewes was slightly coarser in diameter than those of SAMM cross and FW+ ewes, which in turn was coarser than those of Rep+ and Dohne Merino ewes. The economic viability of crossbreeding programs involving the respective ewe lines would depend on the ratio between the prices of wool and lamb. No conclusive advantage could be demonstrated in favour of any of the sire breeds. Keywords: Fibre diameter, Lamb growth, Lamb output, Reproduction, South African sheep breeds, Wool yield South African Journal of Animal Science Vol.33(4) 2003: 223-23

Behaviour response of Namaqua Afrikaner, Dorper and South African Mutton Merino lambs towards humans

The response of Namaqua Afrikaner, Dorper and South African Mutton Merino lambs, of approximately four months of age, towards a human being situated between them and their flock mates was studied in an arena test. The objective of the study was to determine whether the unimproved Namaqua Afrikaner, with an arguably shorter history of selection, would react differently to humans in an arena test compared to commercial breeds. A total number of 305 animals, born in 2010 and 2011 and raised under extensive veld conditions, were assessed in a modified arena test when the lambs born in each year were approximately four months old. From the test results it was possible to calculate the following parameters of the behaviour of the sheep: (i) The mean distance from the human operator, (ii) the time a lamb spent in a specific zone situated either close to or far from the human, and (iii) the total number of boundaries crossed, which gives an indication of the total distance travelled by an individual lamb. Other data recorded were the number of bleats and the number of times an animal urinated or defecated. There were no significant sex and birth type differences for any of the behaviour traits. No conclusive breed differences were found for any of the traits describing the behaviour of the lambs, except for the number of bleats. Namaqua Afrikaner lambs bleated significantly (24.0 ± 1.2) more in the three minute testing period than Dorper (8.2 ± 0.9) and South African Mutton Merino lambs (11.9 ± 2.5). Further research is necessary to see if this slight indication of anxiety could be related to other traits such as lamb survival or product quality.Keywords: Arena test, distance travelled, times defecated, times urinated, sheep, stockman, temperamen

Production of five Merino type lines in a terminal crossbreeding system with Dormer or Suffolk sires

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The effect of breed, ewe age and season on tick counts of indigenous and commercial sheep in South Africa.

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Divergent selection for reproduction affects dag score, breech wrinkle score and crutching time in Merinos

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Divergent selection for reproduction affects dag score, breech wrinkle score and crutching time in Merinos

AgriwetenskappeVeekundige WetenskappePlease help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]