scholarly journals PSXI-40 Body reserves profile and rearing performance of meat ewes are genetically linked

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 387-387
Author(s):  
Eliel González-García ◽  
Tiphaine Macé ◽  
Dominique Hazard
Keyword(s):  
Growth Rate ◽  
Genetic Parameters ◽  
Sheep Population ◽  
Genetic Gains ◽  
Litter Weight ◽  
Body Reserves ◽  
Lamb Growth ◽  
Meat Sheep

Abstract The objective of this work was to study the relationships between different body reserve (BR) dynamic profiles and ewe rearing performance (PERF) traits in a Romane meat sheep population extensively managed in a rangeland of France. Genetic parameters that link litter weight and lamb BW at lambing and weaning, lamb growth rate at 1, 2 and 3 months after lambing and litter survival from lambing to weaning to different BR profiles that have previously been demonstrated in the same animals are reported. Records from the flock of the INRA La Fage experimental farm were used to generate datasets from 14 lambing years (YR: 2002 to 2015). The datasets involved 1,146, 1,072 and 414 females belonging to 3 parities (PAR: 1, 2 and 3, respectively), with first lambing at 2 ages (AGE: 1 or 2-yr-old), and 4 litter sizes (LS: 1, 2, 3 and 4 lambs born alive). Significant effects on PERF were observed on all fixed variables considered (i.e., YR, AGE, PAR and LS). Similarly, the BW and BCS profiles of the ewes were strongly related to the PERFs across the 3 PARs studied, particularly for the BW profiles in the first cycle (PAR 1). In contrast to litter survival, which showed very low h² values and repeatabilities, the traits of lamb BW at lambing and weaning and litter weights at weaning had moderate h² values ranging from 0.20 to 0.23 and repeatabilities ranging from 0.21 to 0.27. In conclusion, our results show that genetic gains may be possible due to the inclusion of combined BR and PERF traits in sheep selection programs for this breed and warrant further research in other sheep populations.

The performance of Masham ewes

1979 ◽  
Vol 29 (1) ◽  
pp. 69-79 ◽  
Author(s):  
J. E. Newton ◽  
J. S. Fenlon
Keyword(s):  
Growth Rate ◽  
Birth Weight ◽  
Perinatal Mortality ◽  
Litter Size ◽  
High Birth Weight ◽  
Litter Weight ◽  
Lamb Growth

ABSTRACTThe performance of two flocks of crossbred Masham ewes (Tees-water × Dales Bred) was measured for 6 and 4 years respectively. The ewes in Flock 1 were mated with Dorset Down rams and the ewes in Flock 2 with Suffolk rams.The overall mean mating weight of each flock was 68-0 kg with no consistent year-to-year variation. The mating weight repeatability values for ewes entering the flocks as 2-year-olds were 0·532 (±0·0681) and 0·524 (±0·1118) for Flocks 1 and 2 respectively.Mean litter size increased with age, but repeatability was low. Over- all litter weights for singles, twins and triplets were 5·89, 9·88 and 12·43 kg respectively. Two-year-old ewes had lighter litters than mature ewes. Repeatability for litter weight in Flock 1 was 0·337 (±0·0755).Lamb growth rate to 4 weeks of age was lower for 2-year-old ewes in both flocks and the repeatability was 0·322 (±0·0947) in Flock 1. For ewes having twin lambs, significant correlations (P < 0·01) were found between mating weight and birth weight and between birth weight and lamb growth rate to 4 weeks of age.Perinatal mortality was higher for lambs with a birth weight below 3·9 kg, but overall lamb mortality was only 8%: this low figure was probably due to the relatively high birth weight of the twin and triplet lambs.

The CAMDA sheep breeding scheme: I. Estimation of genetic parameters for 18-week weight

1999 ◽  
Vol 1999 ◽  
pp. 119-119 ◽  
Author(s):  
A. A. Aslaminejad ◽  
R. M. Lewis ◽  
J. A. Roden ◽  
V.R. Fowler
Keyword(s):  
Growth Rate ◽  
Genetic Parameters ◽  
Live Weight ◽  
Breeding Scheme ◽  
Sheep Breeding ◽  
Group Breeding ◽  
Incomplete Performance ◽  
Mature Size ◽  
Lamb Growth ◽  
Estimation Of Genetic Parameters

The CAMDA group breeding scheme was established in 1976. Its objective is to increase lamb growth rate, mature size and maternal ability of the Welsh Mountain sheep while retaining their hardiness and breed type. The opportunity to achieve this goal depends on the extent of genetic variation within the breed for these traits. The objective of this study was to estimate the amount of variation in 18-week live weight attributable to the lamb genotype (direct) and dam maternal ability, both genetic and environmental, in Welsh Mountain sheep within this scheme.A total of 12954 records of 18-week live weight of Welsh Mountain lambs collected between 1976 and 1995 from 4 flocks of the CAMDA scheme were considered. The data were edited for small contemporary groups and for incomplete performance or pedigree recording.

scholarly journals Genetic parameters for growth, reproductive and maternal traits in a multibreed meat sheep population

2009 ◽  
Vol 32 (4) ◽  
pp. 761-770 ◽  
Author(s):  
Ana Maria Bezerra Oliveira Lôbo ◽  
Raimundo Nonato Braga Lôbo ◽  
Samuel Rezende Paiva ◽  
Sônia Maria Pinheiro de Oliveira ◽  
Olivardo Facó
Keyword(s):  
Genetic Parameters ◽  
Sheep Population ◽  
Meat Sheep

scholarly journals Mammary Gland Structures Are Not Affected by an Increased Growth Rate of Yearling Ewes Post-Weaning but Are Associated with Growth Rates of Singletons

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 884
Author(s):  
Emmanuelle Haslin ◽  
Rene A. Corner-Thomas ◽  
Paul R. Kenyon ◽  
Adrian J. Molenaar ◽  
Stephen T. Morris ◽  
...  
Keyword(s):  
Growth Rate ◽  
Mammary Gland ◽  
Live Weight ◽  
Late Pregnancy ◽  
Control Group ◽  
Early Lactation ◽  
Fat Pad ◽  
Negative Effects ◽  
Lamb Growth ◽  
Heavy Group

The experiment aimed to examine the impacts of an increased growth rate of ewes between three and seven months of age on udder development using ultrasound and to establish whether ultrasonography could be used to identify ewe mammary structures that may be indirect indicators of singleton growth to weaning. Udder dimensions, depths of gland cistern (GC), parenchyma (PAR) and fat pad (FP) were measured in late pregnancy (P107), early lactation (L29), and at weaning (L100) in 59 single-bearing yearling ewes selected from two treatments. The ‘heavy’ group (n = 31) was preferentially fed prior to breeding achieving an average breeding live-weight of 47.9 ± 0.38 kg at seven months of age. The ‘control’ group (n = 28) had an average breeding live-weight of 44.9 ± 0.49 kg. Udder dimensions, GC, PAR and FP did not differ between treatments. Lamb growth to L100 was positively associated (p < 0.05) with PAR at P107 and GC at L29. There was no evidence of negative effects of the live-weight gain treatments on udder development of yearling ewes as measured by ultrasonography. The results suggest that this ultrasound method has the potential to identify pregnant yearling ewes which would wean heavier singletons.

Composite trait selection to improve reproduction and ewe productivity: a review

2009 ◽  
Vol 49 (1) ◽  
pp. 9 ◽  
Author(s):  
G. D. Snowder ◽  
N. M. Fogarty
Keyword(s):  
Individual Component ◽  
Genetic Relationships ◽  
Reproductive Efficiency ◽  
Component Trait ◽  
Litter Weight ◽  
Growth Selection ◽  
Component Traits ◽  
Selection For ◽  
Genetic Responses ◽  
Lamb Growth

Reproduction and ewe productivity are complex composite traits that are influenced by several component traits. Genetic improvement by selection for an individual component trait may not always be advantageous because adverse or neutral genetic relationships can exist among the component traits. Selection for an overall composite trait of ewe productivity, defined as litter weight weaned per ewe joined, can result in a balanced biological composite trait with favourable responses in component traits including fertility, number of lambs born, lamb survival, lactation and lamb growth. Selection for litter weight weaned may also overcome adverse genetic relationships among reproductive component traits. This review examines the genetic responses of selecting directly for litter weight weaned, compared with selection responses for one or more of its component traits. It is concluded that selection to improve reproductive efficiency and ewe productivity, under most production and environmental systems, would benefit from selection for a composite trait such as litter weight weaned, rather than for a single component trait.

PRODUCTION POTENTIAL AND BREEDING SCHEMES OF SOME MEDITERRANEAN DAIRY SHEEP BREEDS

1991 ◽  
Vol 8 ◽  
pp. 13-26 ◽  
Author(s):  
N. P. Zervas ◽  
J. Hatziminaoglou ◽  
J. Boyazoglu ◽  
A. Georgoudis
Keyword(s):  
Genetic Parameters ◽  
Management Practices ◽  
Reproductive Potential ◽  
Dairy Sheep ◽  
Phenotypic Characteristics ◽  
Production Potential ◽  
Sheep Population ◽  
Sheep Breeds ◽  
Breeding Schemes ◽  
The Mediterranean

SUMMARYExaminded are some of the most important dairy sheep breeds, among the great diversity of the Mediterranean sheep population, by focusing on their phenotypic characteristics, their productive and reproductive potential as well as on the management practices and systems of testing. Information is also given on their genetic parameters, with emphasis on heritability coefficients, and the range of respective selection and breeding schemes, applied under their particular husbandry conditions.

Effects of lasalocid and protein levels on feed intake and growth rate of Awassi lambs

1997 ◽  
Vol 1997 ◽  
pp. 187-187
Author(s):  
M. M. Muwalla ◽  
M. Y. Harb ◽  
T. F. Crosby
Keyword(s):  
Growth Rate ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Published Data ◽  
Growth Promoter ◽  
Feed Conversion ◽  
Protein Levels ◽  
Feedlot Lambs ◽  
Lamb Growth ◽  
Awassi Lambs

Lasalocid is a polyether antibiotic derived from the fermentation of streptomyces lasaliensis used as a coccidiostat in sheep. There are varying literature reports on lamb growth rate and feed intake when lasalocid is included in the diet of feedlot lambs. While some reports have shown that lasalocid enhances feed efficiency in ruminants by decreasing feed intake and either maintaining or improving rate of gain others indicate that lasalocid did not have any effect on lamb growth rates or feed efficiency (Stobart et al., 1987). Also, when lasalocid was fed to Chios lambs, growth rate was increased but there was no improvement in feed conversion efficiency (Hadjipanayiotou et al., 1988). There are no published data in the literature relating to the use of lasalocid as a growth promoter in the Awassi breed of sheep fed complete diets and the purpose of this study was to investigate the effect of lasalocid with two levels of protein on the growth rate and feed efficiency of weaned male and female Awassi lambs.

Selection on ram 18-month weight to improve lamb growth rate

1983 ◽  
Vol 36 (2) ◽  
pp. 159-164
Author(s):  
D. Croston ◽  
J. L. Read ◽  
D. W. Jones ◽  
D. E. Steane ◽  
C. Smith
Keyword(s):  
Growth Rate ◽  
Live Weight ◽  
Indirect Selection ◽  
Direct Selection ◽  
Selection For ◽  
The Relationship ◽  
Lamb Growth

ABSTRACTThirteen pairs of Suffolk rams were selected on high and low 18-month adjusted live weight from six farms over 2 years, to establish the relationship between 18-month weight and early lamb growth. Progeny were first produced in recorded crossbred flocks (618 lambs) and then in an experimental flock of crossbred ewes (1083 lambs). Different results were obtained from the recorded and experimental flocks. The regressions of lamb 12- to 13-week weight on ram 18-month weight (within farm deviation) were 0·053 ± 0·022 kg and –0·004 ± 0·020 kg, respectively. These regressions for indirect selection correspond to ‘effective’ heritabilities for direct selection for lamb growth of 0·18 ± 0·07 and 0·02 ± 0·06 respectively. Improvement of early Iamb growth is discussed and it is concluded that selection for 18-month weight is unlikely to be a useful method.

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