Season and reproductive status rather than genetics factors influence change in ewe weight and fat over time. 1. Analysis of crossbred ewes

2014 ◽  
Vol 54 (6) ◽  
pp. 802 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
N. M. Fogarty ◽  
S. Hatcher ◽  
...  
Keyword(s):  
Genetic Correlations ◽  
Adult Life ◽  
Production Cycle ◽  
Strong Correlations ◽  
Multiple Production ◽  
Fat Reserves ◽  
Production Cycles ◽  
Australian Sheep ◽  
Maternal Performance ◽  
Fat Score

The Australian sheep industry has historically made rapid advances in the quality and quantity of meat and wool through genetic improvement, but unfortunately, maternal performance, i.e. number of lambs weaned, is well below desired levels. The aim of the present paper is to investigate the potential to select for increased weight and fat across the production cycle to improve maternal performance. The analysis explores the potential to improve the weight and fat score of breeding ewes during ‘tough’ periods (i.e. when nutrient requirements are not met by the pasture), preparing the breeding ewe for the upcoming mating without an increase in overall ewe size. The 2846 ewes within the maternal central progeny test were weighed and scored for fatness 12 times across three production cycles. Low to moderate heritability estimates for weight (0.04–0.23) and fat (0.02–0.06) changes across the production cycle provide little hope for selection against weight loss during tough periods. The analysis showed very strong genetic correlations between time-points across multiple production cycles for both weight (0.99–0.93) and fat score (0.88–0.98). The very strong correlations between measurements suggest that weight and fat score are genetically the same trait throughout the ewe’s adult life. With 74% and 77% of the genetic variation in weight and fat, respectively, constant across the production cycle, there is little opportunity to select against the natural fluctuations in weight and fat reserves. In conclusion, selection for increased fat can be made at any time and it will result in more fat during tough times.

Season and reproductive status rather than genetic factors influence change in ewe weight and fat over time 2. Spline analysis of crossbred ewes

2014 ◽  
Vol 54 (6) ◽  
pp. 814 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
N. M. Fogarty ◽  
S. Hatcher ◽  
...  
Keyword(s):  
Genetic Factors ◽  
Genetic Effects ◽  
Low Fertility ◽  
Production Cycle ◽  
Fat Reserves ◽  
Variable Environments ◽  
Maternal Performance ◽  
Fat Score ◽  
Sire Breed ◽  
Over Time

The success of slaughter lamb enterprises is heavily influenced by the ability of the breeding ewe to produce a lamb annually across variable environments. It has been shown that by maintaining heavier weight and condition across the annual production cycle producers can make significant improvements in maternal performance. This paper follows on from a previous analysis of crossbred ewes within the Maternal Central Progeny Test and examines the potential to select for reduced fluctuation in weight and fat across the production cycle. A cubic spline model was fitted to the weight and fat score data from the first three parities of 2688 first-cross ewes. The analysis partitioned the influence of environment, reproduction and genetic effects on the shape of the weight and fat score splines across three parities. Yearly and seasonal variation in feed supply and the demands of raising a lamb are the major influences on fluctuations in the weight and fat score of the breeding ewe. The genetic effects were constant across time with 98 and 92% of the genetic variation for weight and fat, respectively, associated with the spline’s intercept. In agreement with the findings of the first paper of the series it can be concluded that genetic lines do not re-rank for weight or fat score over time. The influence of sire breed on weight and fat score was constant across time with sire breeds fluctuating in parallel across time. As a result it is concluded that to avoid low fat reserves and the subsequent low fertility during the ‘tough’ periods, selection to improve ewe body condition could be made at any time and under any environmental conditions.

Recent trends in pig production: the importance of intake

1989 ◽  
Vol 13 ◽  
pp. 1-5 ◽  
Author(s):  
J. E. Riley
Keyword(s):  
Food Intake ◽  
Growth Traits ◽  
Meat Production ◽  
Production Cycle ◽  
Limiting Factor ◽  
New Production ◽  
Fat Reserves ◽  
Production Cycles ◽  
The Individual ◽  
The Uk

AbstractThe UK pig industry has shown an ability to respond quickly to changing market requirements and improving efficiency of pig meat production. Rapid genetic improvement in breeding stock, particularly in carcass quality and growth traits, together with the adoption of new production strategies, have been the main factors. These changes have had major implications for the way pigs are fed at all stages of the production cycles. Market forces have resulted in a pig population with reduced fat reserves and low appetite. Food intake is a limiting factor at several stages of the production cycle including post weaning, in the case of early-weaned piglets, and the management of young lactating sows. Knowledge of the daily nutrient requirements of the individual animal far exceeds the ability to ensure that those requirements are satisfied by feeding systems in commercial use. Manipulation of food intake to achieve optimum profit is the weakest link in the UK producers' knowledge.

Season and reproductive status rather than genetics factors influence change in ewe weight and fat over time. 3. Analysis of Merino ewes

2014 ◽  
Vol 54 (6) ◽  
pp. 821 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
S. I. Mortimer ◽  
W. S. Pitchford
Keyword(s):  
Genetic Variation ◽  
Body Condition ◽  
Production Systems ◽  
Genetic Effect ◽  
Additive Genetic Effect ◽  
Production Cycle ◽  
Production Cycles ◽  
Australian Sheep ◽  
Sheep Production ◽  
Stocking Rates

The profitability of southern Australian sheep production systems depends on the optimisation of stocking rates by meeting the nutritional demands of the breeding ewe while effectively utilising grown pasture. The aim of the study was to evaluate the genetic variation in liveweight and body condition of Merino ewes across their breeding life within a wool-based enterprise. The results were consistent with findings in crossbred ewes and showed that the genetic component of weight and body condition remained constant across the production cycle and age. The overall additive genetic effect accounted for 92% of the genetic variation in weight of Merino ewes bred across five production cycles. A genetic correlation of 0.85 suggested that ewes that were superior at maintaining their condition when rearing a single lamb would maintain this superiority when rearing multiple lambs. To improve weight and condition of Merino ewes during the ‘tough’ times, when nutrient requirements are not met by the pasture, selection can be made at any time and this will result in increased genetic condition at all times.

Seasonal changes in tissue weights in Scottish Blackface ewes over multiple production cycles

2004 ◽  
Vol 79 (3) ◽  
pp. 373-385 ◽  
Author(s):  
N. R. Lambe ◽  
G. Simm ◽  
M. J. Young ◽  
J. Conington ◽  
S. Brotherstone
Keyword(s):  
Litter Size ◽  
Seasonal Changes ◽  
Genetic Correlations ◽  
Age Groups ◽  
Annual Production ◽  
Random Regression ◽  
Production Cycle ◽  
Muscle Weight ◽  
Multiple Production ◽  
Different Ages

AbstractHill ewes undergo large changes in body fat and muscle weight throughout the annual production cycle as they contend with the pressures of reproduction and lactation, as well as harsh environmental conditions. This study modelled seasonal changes in fat and muscle weights in Scottish Blackface hill ewes throughout their productive lifetime using random regression statistical techniques.Scottish Blackface ewes (no. = 308) were scanned using computed tomography (CT) four times per year, from 2 until 5 years old. Heritabilities of tissue weights were estimated at 2-weekly intervals throughout the productive life of the ewe. Genetic correlations between tissue weights at the same point in the production cycle at different ages, and between tissue weights at different events within each annual production cycle were predicted. Animal solutions from random regression analyses were used to estimate tissue weights, from pre-mating at 2 years old to weaning at 5 years old. The effects of litter size in the current and previous production years on fat and muscle weights were investigated.Correlations between CT tissue weights and those predicted by a sin/cos random regression model were 0.87, 0.84, 0.88 for carcass fat, internal fat and muscle respectively. Heritabilities ranged from 0.31 to 0.90 for carcass fat weight, 0.21 to 0.68 for internal fat weight and 0.26 to 0.57 for muscle weight, throughout the productive lifetime of the ewe. Heritabilities were highest during mating for fat weights, and during the dry period and lambing time for muscle weights. Heritabilities of tissue weights in 3-year-old ewes were higher than in other age groups. Genetic correlations were 1.00 between tissue weights at the same scanning event at different ages, but ranged from close to zero to 0.97 between scanning events within age groups. Clearly environmental variation across time was large. The number of lambs produced in both the current and the previous year influenced tissue levels. Ewes that did not produce lambs (barren) in a given year carried more muscle during that year than ewes producing lambs. As ewes aged, barren ewes carried increasingly more carcass fat and muscle than ewes with lambs. Barren ewes also had significantly more muscle during the following year than ewes that had weaned lambs. Ewes that reared twins had significantly less carcass fat the following year than singleton-bearing or barren ewes. These effects of previous litter size increased significantly with age.

scholarly journals Epidemiology ofCampylobacterspp. at two Dutch broiler farms

1995 ◽  
Vol 114 (3) ◽  
pp. 413-421 ◽  
Author(s):  
W. F. Jacobs-Reitsma ◽  
A. W. Van de Giessen ◽  
N. M. Bolder ◽  
R. W. A. W. Mulder
Keyword(s):  
Horizontal Transmission ◽  
Conclusive Evidence ◽  
Production Cycle ◽  
Epidemiological Factors ◽  
Broiler Flock ◽  
Water Feed ◽  
Production Cycles ◽  
Darkling Beetles ◽  
Fresh Litter ◽  
Broiler House

SUMMARYBroiler flocks on two Dutch poultry farms were screened weekly for the presence of Campylobacter in fresh caecal droppings during eight consecutive production cycles. Hatchery and fresh litter samples were taken at the start of each new cycle. Water, feed, insects, and faeces of domestic animals, present on the farms were also included in the sampling. Penner seretyping of isolates was used to identify epidemiological factors that contribute to Campylobacter colonization in the broiler flocks. Generally, broiler flocks became colonized with Campylobacter at about 3–4 weeks of age with isolation percentages of 100%, and stayed colonized up to slaughter. A similar pattern of serotypes was found within the various broiler houses on one farm during one production cycle. New flocks generally showed also a new pattern of serotypes. Most serotypes isolated from the laying hens, pigs, sheep and cattle were different from those isolated from the broilers at the same time. Campylobacter serotypes from darkling beetles inside the broiler houses were identical to the ones isolated from the broilers. No Campylobacter was isolated from any of the hatchery, water, feed or fresh litter samples. Conclusive evidence of transmission routes was not found, but results certainly point towards horizontal transmission from the environment. Horizontal transmission from one broiler flock to the next one via a persistent contamination within the broiler house, as well as vertical transmission from breeder flocks via the hatchery to progeny, did not seem to be very likely.

Season and reproductive status rather than genetic factors influence change in ewe weight and fat over time. 4. Genetic relationships of ewe weight and fat score with fleece, reproduction and milk traits

2016 ◽  
Vol 56 (4) ◽  
pp. 708 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
N. M. Fogarty ◽  
S. Hatcher ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Fat ◽  
Genetic Relationships ◽  
Fibre Diameter ◽  
Reproductive Traits ◽  
Production Cycle ◽  
Production Traits ◽  
Milk Production Traits ◽  
Milk Traits ◽  
Fat Score

The profitability of a sheep enterprise is greatly influenced by the ability of the ewe to produce a lamb annually. This paper examines the between- and within-breed association between the liveweight and fat score of the adult ewe and key fleece, reproduction and milk production traits. The study analysed the performance of 2846 first-cross Merino and Corriedale ewes from the maternal central progeny test (MCPT) over their first three production cycles. Breed (9 sire breeds) and within-breed (91 sires) correlations were calculated from bivariate correlations of adult liveweight and fat score with fleece, reproduction and milk production traits. The mean liveweight and fatness of the breeds were low to moderately negatively correlated with greasy fleece weight (–0.55 and –0.25, respectively) and moderate to strongly positively correlated with fibre diameter (0.88 and 0.41, respectively). However, the within-breed correlations were generally low to negligible. The genetic relationships between ewe fat score and reproductive traits at the breed and within-breed level was generally low to negligible and, in some cases, negative under production conditions where the ewes were well managed and averaged a fat score of 3.5 pre-joining and became too fat across the production cycle. Strong breed correlations between ewe fat score and milk fat concentration (0.88) suggest that selection of fatter sire breeds will lead to increased fat in their progenies’ milk, which was associated with larger lambs. The potential advantages of selecting for more fat to improve the maternal performance of the ewe seem to be limited in enterprises where the production system can easily be adjusted to restrict the influence of temporary and long-term feed deficiencies, as was achieved within the MCPT research flocks.

Genetic parameters for lamb autopsy traits

2014 ◽  
Vol 54 (6) ◽  
pp. 736 ◽  
Author(s):  
D. J. Brown ◽  
R. M. Jones ◽  
G. N. Hinch
Keyword(s):  
Genetic Correlations ◽  
Selection Criterion ◽  
Research Centre ◽  
Cooperative Research ◽  
Crown Rump Length ◽  
Australian Sheep ◽  
Lamb Survival ◽  
Fleece Weight ◽  
Indicator Traits ◽  
Overall Mortality

Heritabilities and genetic correlations were estimated between individual and composite autopsy traits for lambs autopsied in the Australian Sheep Cooperative Research Centre information nucleus flocks between 2008 and 2011 (n = 3224). Correlations were also estimated between autopsy categories and the production parameters Yearling greasy-fleece weight and Yearling weight, and the potential survival indicator traits: Lamb ease, Thorax circumference and Crown–rump length. All autopsy trait heritability estimates were low (range 0.01–0.04). For all traits, a higher proportion of the variance was partitioned into the maternal permanent environment than the direct effects (range 0.01–0.12), suggesting that selection based on lamb autopsy results would impart little advantage over the lamb survival trait itself in improving lamb survival. Genetic correlations between Lamb ease and all autopsy traits were positive, indicating that birth trauma is related to all causes of lamb deaths and that Lamb ease may be a useful selection criterion in seedstock flocks to reduce overall mortality. There were also positive genetic correlations between Thorax circumference after adjusting for birthweight and two classes of dystocia, as well as a positive correlation between Thorax circumference and incidences of Starvation mismothering, implying that Thorax circumference may be a useful indirect field measurement to reduce death from these causes. Of concern were the antagonistic genetic correlations estimated between Yearling greasy-fleece weight and a composite trait of All Dystocia classes plus Starvation mismothering (0.27 ± 0.15), implying that selection for increased fleece weight could be having a detrimental effect on overall lamb survival.

scholarly journals Relationships between body reserve dynamics and rearing performances in meat ewes1

2019 ◽  
Vol 97 (10) ◽  
pp. 4076-4084
Author(s):  
Tiphaine Macé ◽  
Dominique Hazard ◽  
Fabien Carrière ◽  
Sebastien Douls ◽  
Didier Foulquié ◽  
...  
Keyword(s):  
Genetic Relationships ◽  
Genetic Correlations ◽  
Repeated Measurements ◽  
Production Cycle ◽  
Data Sets ◽  
Data Set ◽  
Litter Weight ◽  
Significant Relationships ◽  
Physiological Stage ◽  
Changes Over Time

Abstract The main objective of this work was to study the relationships between body reserve (BR) dynamics and rearing performance (PERF) traits in ewes from a Romane meat sheep flock managed extensively on “Causse” rangelands in the south of France. Flock records were used to generate data sets covering 14 lambing years (YR). The data set included 1,146 ewes with 2 ages of first lambing (AGE), 3 parities (PAR), and 4 litter sizes (LS). Repeated measurements of the BW and BCS were used as indicators of BR. The ewe PERF traits recorded were indirect measurements for maternal abilities and included prolificacy, litter weight and lamb BW at lambing and weaning, ADG at 1, 2, and 3 mo after lambing, and litter survival from lambing to weaning. The effects of different BW and BCS trajectories (e.g., changes in BW and BCS across the production cycle), previously been characterized in the same animals, on PERF traits were investigated. Such trajectories reflected different profiles at the intraflock level in the dynamics of BR mobilization–accretion cycles. Genetic relationships between BR and PERF traits were assessed. All the fixed variables considered (i.e., YR, AGE, PAR, LS, and SEX ratio of the litter) have significant effects on the PERF traits. Similarly, BW trajectories had an effect on the PERF traits across the 3 PARs studied, particularly during the first cycle (PAR 1). The BCS trajectories only affected prolificacy, lamb BW at birth, and litter survival. Most of the PERF traits considered here showed moderate heritabilities (0.17–0.23) except for prolificacy, the lamb growth rate during the third month and litter survival which showed very low heritabilities. With exception of litter survival and prolificacy, ewe PERF traits were genetically, strongly, and positively correlated with BW whatever the physiological stage. A few weak genetic correlations were found between BCS and PERF traits. As illustrated by BW and BCS changes over time, favorable genetic correlations were found, even if few and moderate, between BR accretion or mobilization and PERF traits, particularly for prolificacy and litter weight at birth. In conclusion, our results show significant relationships between BR dynamics and PERF traits in ewes, which could be considered in future sheep selection programs aiming to improve robustness.

Winter corticosterone and body condition predict breeding investment in a nonmigratory bird

2019 ◽  
Vol 30 (6) ◽  
pp. 1642-1652 ◽  
Author(s):  
Chloé Montreuil-Spencer ◽  
Kelsey Schoenemann ◽  
Ádám Z Lendvai ◽  
Frances Bonier
Keyword(s):  
Life History ◽  
Breeding Season ◽  
Body Condition ◽  
Reproductive Investment ◽  
Phenotypic Traits ◽  
Residual Body ◽  
Life History Stage ◽  
Nonbreeding Season ◽  
Fat Reserves ◽  
Fat Score

Abstract Reproduction is an energetically demanding life history stage that requires costly physiological and behavioral changes, yet some individuals will invest more into reproduction and breed more successfully than others. To understand variation in reproductive investment, previous studies have evaluated factors during breeding, but conditions outside of this life history stage may also play a role. Using a free-ranging population of black-capped chickadees (Poecile atricapillus), we assessed the repeatability of plastic traits relating to energetic condition (circulating initial corticosterone concentrations and body condition) during the nonbreeding season and evaluated whether these traits predicted reproductive investment in the subsequent breeding season. We found that initial corticosterone concentrations and an index of body condition, but not fat score, were moderately repeatable over a 1-week period in winter. This trait repeatability supports the interpretation that among-individual variation in these phenotypic traits could reflect an intrinsic strategy to cope with challenging conditions across life history stages. We found that females with larger fat reserves during winter laid eggs sooner and tended to spend more time incubating their eggs and feeding their offspring. In contrast, we found that females with higher residual body mass delayed breeding, after controlling for the relationship between fat score and timing of breeding. Additionally, females with higher initial corticosterone in winter laid lighter eggs. Our findings suggest that conditions experienced outside of the breeding season may be important factors explaining variation in reproductive investment.

scholarly journals Effects of Elevated Platform and Robotic Vehicle on Broiler Production, Welfare, and Housing Environment

2020 ◽  
Vol 63 (6) ◽  
pp. 1981-1990
Author(s):  
Xiao Yang ◽  
Xiaojing Huo ◽  
Guoming Li ◽  
Joseph L. Purswell ◽  
George T. Tabler ◽  
...  
Keyword(s):  
Moisture Content ◽  
Activity Index ◽  
Production Performance ◽  
Production Cycle ◽  
List Type ◽  
Feed Conversion ◽  
Housing Environment ◽  
Broiler Production ◽  
Production Cycles ◽  
Robotic Vehicle

HighlightsUsing an elevated platform with a manure catcher reduced litter moisture content and ammonia concentration.A robotic vehicle encouraged bird movement and use of the elevated platform.Using the elevated platform and robotic vehicle jointly improved broiler paw quality and plumage cleanliness.Abstract. Elevated platform (EP) and robotic vehicle (RV) are two emerging systems aiming to improve environment enrichment and bird activity in broiler housing systems. However, the impacts of these systems on broiler production, welfare, and housing environment have not been evaluated. The objective of this study was to evaluate the effects of using EP and RV individually or jointly on broiler feed conversion ratio (FCR), litter moisture content (LMC), ammonia (NH3) concentration, gait score (GS), paw quality (PQ), plumage cleanliness (PC), and bird activity index (AI). Broilers were reared for eight-week production cycles. Four experimental rooms (54 birds room-1) were randomly assigned four treatments: EP only, RV only, EP and RV (EP+RV), and neither EP nor RV (Ctrl). Broiler GS, PQ, and PC were assessed following welfare protocols. Bird AI was determined through image processing. The experiment was repeated three times. The results showed that overall FCR values were 1.806 for EP, 1.804 for RV, 1.797 for EP+RV, and 1.791 for Ctrl. The normalized LMC values were 23.2% ±4.1% for EP, 32.8% ±4.1% for RV, 23.4% ±2.5% for EP+RV, and 35.7% ±7.0% for Ctrl over the eight-week production cycles. NH3 concentrations were 40% lower in the rooms with EP than in the rooms without EP at the end of the production cycle. Broilers had better PQ in the rooms with EP than in the rooms without EP. Broiler PC seemed better in the rooms with RV compared to those without RV. Operation of RV increased bird AI; however, the benefits in activity encouragement diminished as the broilers grew. The number of broilers on the EP was higher in the EP+RV rooms than in the EP rooms. It is concluded that using EP and RV together may improve broiler welfare and activity without compromising their production performance. Keywords: Behavior, Broiler, Elevated platform, Robotic vehicle, Welfare.

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