Impact of liveweight, fat and muscle sire breeding values on ewe reproduction is minimal but variable across Australian grazing systems

2017 ◽  
Vol 57 (9) ◽  
pp. 1952 ◽  
Author(s):  
S. F. Walkom ◽  
D. J. Brown
Keyword(s):  
Body Condition ◽  
Reproductive Performance ◽  
Breeding Value ◽  
Production Cycle ◽  
Eye Muscle ◽  
Breeding Values ◽  
Reproduction Traits ◽  
Reproductive Rates ◽  
Supplementary Feed ◽  
The Impact

Australian sheep producers have the potential to improve reproductive rates through optimising ewe body condition across the production cycle. Managing ewe body condition can become costly when supplementary feeding is required due to poor pasture growth or rainfall and by using appropriate genetics, producers can theoretically reduce the flock’s dependency on supplementary feed and improve reproductive rates. Reproductive records from the Information Nucleus Flock and Sheep Genetics Merino and maternal breed datasets were analysed to examine the influence of sire breeding values for liveweight (post-weaning, yearling and adult assessments), fat and eye muscle depths (post-weaning and yearling assessments) and number of lambs weaned on reproductive performance (fertility, litter size and number of lambs born) across a variety of production environments. To determine the impact of environmental conditions on the relationship between weight, ultrasound body composition, and reproduction traits the daughters’ adjusted reproductive performances were regressed on the sire’s breeding value across flocks, within flocks and within flock × year. Irrespective of age at assessment, sire breeding values for liveweight, fat and eye muscle depths had very little association with the reproductive performance of their daughters, on average. The regressions of reproduction on weight, and fat and eye muscle depth traits varied across flocks from unfavourable to favourable estimates. The very small overall impact of weight, and fat and eye muscle depth traits, on average suggests that using sire breeding values for number of lambs weaned, which had a large impact on reproduction, will provide the most viable method to genetically improve reproductive performance within the production system in question.

Long-term reproductive patterns and sighting bias in Weddell seals (Leptonychotes weddelli)

1987 ◽  
Vol 65 (5) ◽  
pp. 1091-1099 ◽  
Author(s):  
J. Ward Testa
Keyword(s):  
Reproductive Performance ◽  
Age At First Reproduction ◽  
Reproductive Patterns ◽  
Weddell Seals ◽  
Signy Island ◽  
First Reproduction ◽  
Reproductive Rates ◽  
The Cost ◽  
The Impact

The reproductive performance of tagged Weddell seals (Leptonychotes weddelli) was monitored at McMurdo Sound, Antarctica, from 1970 to 1984. An age-specific reproductive schedule revealed the major onset of pupping at age 6 years, and a mean age of first birth of 7.1 years. The average asymptotic pupping rate of 0.61 is reached by age 10. The cost of pupping in a given year is reflected in a 0.05 drop in the probability of pupping the following year. This cost is not evident in females over 7 years old, suggesting that postweaning condition affects newly mature females more than those that are fully mature. Annual adult reproductive rates ranged from 0.46 to 0.79, with a possible periodicity of 5 to 6 years. Simulations were conducted to determine the impact on reproductive estimates of sighting biases associated with seals having had at least one pup (Parous) or having pupped that season (With-Pup). Age at first reproduction as deduced from an age-specific pupping schedule is strongly affected by both forms of sighting bias, but bias in sighting Parous females was the more important. Estimates of adult reproduction were affected minimally. Comparisons of reproductive estimates with those of Weddell seals at Signy Island are discussed with regard to the effects of sighting biases.

Ewe culling and retention strategies to increase reproductive rates in Merino sheep

2018 ◽  
Vol 58 (8) ◽  
pp. 1545 ◽  
Author(s):  
S. Hatcher ◽  
S. Dominik ◽  
J. S. Richards ◽  
J. Young ◽  
J. Smith ◽  
...  
Keyword(s):  
Reproductive Performance ◽  
Reproductive Rate ◽  
Retention Strategies ◽  
Marginal Benefit ◽  
Selection Strategies ◽  
Single Strategy ◽  
Scan Data ◽  
Reproductive Rates ◽  
Breeding Efficiency ◽  
The Impact

The present empirical study of data from three Merino resource flocks of varying genetic backgrounds run in different environments investigated the impact of various selection strategies aimed at culling poor performers (‘passengers’) or retaining good doers (‘performers’) longer, or both, on the flock reproductive performance. Four strategies were investigated and applied either individually or in combination, to quantify their impact on the litter size, rearing type and breeding efficiency (number of lambs weaned per ewe per year) of the whole flock. The main benefit from implementing any of the strategies was a decrease in the proportion of dry ewes in each flock (1–7%). There was little difference between the single strategies of culling twice-dry ewes or culling ewes that twice lambed and lost their lambs. When retaining a cohort of older ewes, it was more efficient to select these on the basis of their lifetime reproductive performance. There was only a marginal benefit gained by combining strategies and, in some cases, a single strategy was still better in terms of breeding efficiency. Commercial producers can improve the reproductive rate of these flocks by culling twice-dry ewes on the basis of their pregnancy scan data.

scholarly journals Quantitative traits under selection: derivations of distributions, higher moments, and the effects of recombination

2021 ◽  
Author(s):  
Reginald D Smith
Keyword(s):  
Quantitative Traits ◽  
Exact Formula ◽  
Breeding Value ◽  
Breeding Values ◽  
Mean And Variance ◽  
The Mean ◽  
The Impact ◽  
First Four Moments ◽  
First Time ◽  
Fertile Area

The mathematical theory of quantitative traits is over one hundred years old but it is still a fertile area for research and analysis. However, the effects of selection on a quantitative trait, while well understood for the effects on the mean and variance, have traditionally been difficult to attack from the perspective of analyzing the probability density of the breeding values and deriving higher (third and fourth) moments as well as analyzing the impact of recombination. In this paper, the exact formula for the breeding value distribution after selection is derived and, using new integral tables, the first four moments are given exact expressions for the first time. In addition, the effects of recombination on the full distribution of breeding values are demonstrated. Finally, the changes of GXE covariance in the selected parent population caused by factors similar to the Bulmer Effect are also investigated in detail.

scholarly journals К проблеме использования инбридинга в мясном скотоводстве

2018 ◽  
Vol 8 (1) ◽  
pp. 596-600
Author(s):  
A.N. Ugnivenko
Keyword(s):  
Growth Rate ◽  
Reproductive Performance ◽  
Negative Impact ◽  
Breeding Value ◽  
Cattle Breeding ◽  
Maternal Line ◽  
Breeding Values ◽  
Reproductive Ability ◽  
Milk Performance ◽  
Males And Females

<p><span lang="EN-US">The influence of homogenous and heterogenous mating of parents on female productivity and breeding value of the sires of Ukrainian Beef has been studied. Inbred males and females have different breeding values in meet cattle breeding. Large number of improvers of growth rate were found among the sires, obtained from related mating. In females, inbred depression by growth rate, reproductive performance and milk performance has been observed. Cows, obtained from the linebreeding had the lowest milk performance and reproductive ability. It is not recommended to use related mating in meet cattle breeding</span><span lang="EN-US">for females obtaining, due to inbred depression. Mating of parents with inbreeding to the maternal line ancestor or “mediator” leads to heterosis by milk and reproductive ability. Heterogenity of parents by indexes of antigen similarity (r<sub>as</sub>) or body tallness index (IBT) reduces the negative impact of inbreeding. Inbreeding</span><span lang="EN-US">applied</span><span lang="EN-US">on</span><span lang="EN-US">parents</span><span lang="EN-US">that</span><span lang="EN-US">were</span><span lang="EN-US">different</span><span lang="EN-US">by</span><span lang="EN-US">conformation type and ancestry is less risky as compared to homogenous animals.</span></p>

Body condition score and reproductive performance in dairy cows in Greece

2007 ◽  
Vol 2007 ◽  
pp. 60-60
Author(s):  
G. Oikonomou ◽  
G. Arsenos ◽  
G.E. Valergakis ◽  
A. Tsiaras ◽  
G. Banos
Keyword(s):  
Dairy Cows ◽  
Body Condition ◽  
Reproductive Performance ◽  
Energy Content ◽  
Body Condition Score ◽  
Reliable Estimate ◽  
Condition Score ◽  
Body Condition Scoring ◽  
Body Energy ◽  
The Impact

Various studies in dairy cows have shown that their Body Condition Score (BCS) effectively reflects their nutritional status and energy content (Ferguson et al. 1994). Extremes in BCS and BCS losses have been identified as a risk factor for health problems and reduced reproductive efficiency (Markusfeld et al. 1997, Lopez-Gatius et al. 2003). Body condition scoring is easy and inexpensive to perform and gives a reliable estimate of body energy reserves. Hence, in practice, BCS can be used as a tool for ration formulation and management decisions concerning reproduction of dairy cows (Banos et al. 2004). The objective of this study was to determine and quantify the impact of BCS in the reproductive performance of primiparous Holstein cows.

scholarly journals Effect of DGAT1, BTN1A1, OLR1, and STAT1 genes on milk production and reproduction traits in the Czech Fleckvieh breed

2014 ◽  
Vol 59 (No. 2) ◽  
pp. 45-53 ◽  
Author(s):  
J. Rychtářová ◽  
Z. Sztankóová ◽  
J. Kyselová ◽  
V. Zink ◽  
M. Štípková ◽  
...  
Keyword(s):  
Milk Production ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Breeding Value ◽  
Production Traits ◽  
Milk Production Traits ◽  
Heterogeneous Effects ◽  
Reproduction Traits ◽  
Estimated Breeding Value ◽  
The Impact

The impact of polymorphism of the diacylglycerol acyltransferase (DGAT1), butyrophilin (BTN1A1), oxidized low-density lipoprotein receptor (OLR1), and signal transducer and activator of transcription 1 (STAT1) genes on milk production and reproduction traits in 419 Czech Fleckvieh cows was examined using polymerase chain reaction and restriction fragment length polymorphism. The loci DGAT1 and BTN1A1 were observed simultaneously to affect milk production, estimated breeding value of milk production traits, as well as reproduction parameters. Significant differences were found also between genotypes of the STAT1 loci in relation to estimated breeding value of milk production traits. Similar findings in pure dairy breeds suggest that heterogeneous effects of the observed loci can be explained by different genetic backgrounds in various breed populations selected to achieve different commercial goals. Thus, it is necessary to determine variability and influence of a molecular marker in a specific population when considering its inclusion into a breeding programme. &nbsp;

Influence of feeding different types feed blocks as supplementary feed on the reproductive performance of Awassi ewes grazing cereal stubble

2005 ◽  
Vol 29 (1) ◽  
pp. 143-151
Author(s):  
A. D. Salman
Keyword(s):  
Cottonseed Meal ◽  
Body Condition ◽  
Reproductive Performance ◽  
Body Condition Score ◽  
Live Weight ◽  
Mating Period ◽  
Different Types ◽  
Condition Score ◽  
Supplementary Feed ◽  
Lambing Rate

This study was conducted to investigate the Influence of feeding different types feed blocks as supplementary feed on the reproductive performance of Awassi ewes grazing cereal stubble. These types were feed blocks enriched with cottonseed meal (CSM) or Brewers’ grain (BG) as sources undegradable protein (UDP). Ninety-six Awassi ewes (mean live weight 42.2 Kg), aged 3-4 years were allocated into three groups according to ewes live weight and body condition score.Group (C): Control (No Supplement) stubble grazing only.Group (FBC): FB enriched with CSM supplement plus stubble grazing.Group (FBB): FB enriched with BG supplement plus stubble grazing.All ewes were run as one flock during cereal stubble grazing. The feed blocks were fed to animals (supplementary groups) after their return from grazing wheat and barley stubble (28 days prior to mating and 54 days after introduction of rams). Rams run with the flock during the mating period. The results showed that feeding feed blocks enriched with CSM and BG as supplementary feed resulted considerable improvement in weight gain (P<0.05), body condition score (P<0.05), conception rate (13-16), lambing percentage (25-33%), twinning percentage (13-18%) and decreased the proportion of barren ewes (19 vs. 6 and 3%). Inclusion of small amount of high moisture brewers grain by-product (9%) as sources of undegradable protein in the feed blocks formula as replacement for costly cottonseed meal resulted a dramatic effects on the reproductive performance of Awassi ewes especially twinning rates and lambing rate.

Using Australian Sheep Breeding Values to increase lean meat yield percentage

2010 ◽  
Vol 50 (12) ◽  
pp. 1098 ◽  
Author(s):  
G. E. Gardner ◽  
A. Williams ◽  
J. Siddell ◽  
A. J. Ball ◽  
S. Mortimer ◽  
...  
Keyword(s):  
Carcass Composition ◽  
Production Traits ◽  
Eye Muscle ◽  
Meat Yield ◽  
Sheep Breeding ◽  
Breeding Values ◽  
Lean Meat ◽  
Target Weight ◽  
Australian Sheep ◽  
The Impact

This study describes the impact of Australian Sheep Breeding Values (ASBV) for post-weaning weight (PWWT), C-site fatness (PFAT) and eye muscle depth (PEMD) on lamb carcasses within the Australian Sheep Industry CRC Information Nucleus Flock. These results are taken from the 2007 drop progeny, consisting of ~2000 lambs slaughtered at a target weight of 21.5 kg. These lambs were the progeny of sires selected to ensure genetic diversity across various production traits. As expected, the PWWT ASBV increased weight at slaughter, and hot standard carcass weight. Dressing percentage was markedly improved by increasing PEMD ASBV, thus prime lamb producers will be maintaining an animal of similar weight on farm, but delivering a markedly larger carcass at slaughter. Lean meat yield % (LMY%) was highest in the progeny of sires with low PFAT ASBV, which decreased whole carcass fatness and increased muscularity. PWWT ASBV affected carcass composition but had little impact on LMY%, as the decreased fatness was largely offset by increased bone, with relatively little change in muscle content. Lastly, PEMD ASBV had little impact on whole carcass LMY%, but did appear to cause some level of muscle redistribution to the higher value loin cuts, in turn increasing the value of the carcass lean.

scholarly journals Association of HindIII-polymorphism in kappa-casein gene with milk, fat and protein yield in holstein cattle*

2018 ◽  
Vol 65 (3) ◽  
Author(s):  
Martina Miluchová ◽  
Michal Gábor ◽  
Juraj Candrák ◽  
Anna Trakovická ◽  
Kristína Candráková
Keyword(s):  
Information Content ◽  
Milk Production ◽  
Polymorphism Information Content ◽  
Milk Fat ◽  
Breeding Value ◽  
Holstein Cattle ◽  
Cattle Population ◽  
Effective Number ◽  
Breeding Values ◽  
The Impact

The aim of the paper was to evaluate the effect of genetic polymorphism of kappa-casein on the milk production in Holstein cattle. A total 210 cows of Holstein cattle were use in this study. On the basis of PCR-RFLP analyses we established genotype structure of cattle population and calculated allelic frequencies. In Holstein cattle population was detected all three genotypes – AA (69.52%), AB (27.62%) and BB (2.86%). The frequency of allele A was 83.33% and allele B was 16.67%. Effectiveness of allele incidence and genetic diversity was evaluated with following parameters: theoretical heterozygosity (Heexp), experimental heterozygosity (Heobs), polymorphism information content (PIC), expected homozygosity (E), effective number of alleles (ENA), level of possible variability realization (V%). The Holstein cattle kept in Slovak Republic exhibit high value of homozygosity and low values of polymorphism information content, effective number of alleles and level of possible variability realization. The effect of polymorphism of CSN3 gene on average breeding values for milk production traits as the yield of milk, fat and protein in kilograms as well as contents of fat and protein in percentages was detected using by the packed SAS 9.3 of SAS Enterprise Guide 5.1. We detected statistical significant difference between genotypes only at an average breeding value for the percentage of protein in milk during assessment the variability of observed traits in depending on polymorphism of CSN3 gene. For other breeding values the impact of individual genotypes CSN3 gene on their variability was not observed.

Genetic evaluation of adult ewe bodyweight and condition: relationship with lamb growth, reproduction, carcass and wool production

2017 ◽  
Vol 57 (1) ◽  
pp. 20 ◽  
Author(s):  
S. F. Walkom ◽  
D. J. Brown
Keyword(s):  
Genetic Variation ◽  
Body Condition ◽  
Current Practice ◽  
Genetic Relationships ◽  
Physiological Status ◽  
Production Cycle ◽  
Production Traits ◽  
Wool Production ◽  
The Impact ◽  
Lamb Growth

This paper reports on genetic variation in the growth, wool production, carcass, reproduction and the bodyweight and body condition of ewes managed in the Information Nucleus Flock (INF), with a focus on evaluating the potential value of including adult ewe bodyweight and condition change traits in the Australian national sheep genetic evaluations provided by Sheep Genetics. Data were collected over a 7-year period (2007–2013) at eight research sites across southern Australia. Approximately 13 700 ewes were weighed and condition scored with ewes on average mated four times during the study. Adult ewe weight and body condition were recorded across the production cycle and the impact of the physiological status and change in status of the ewe on the genetic relationships with lamb growth, carcass and wool production traits was evaluated. Strong genetic correlations between measurements across the production cycle for adult ewe bodyweight and condition, low heritability of change traits, along with weak genetic relationships between change traits and key production traits suggest that in production systems where nutritional challenges can be managed, change traits provide no improvement to the current practice of using static bodyweight and condition records. The genetic variation in weight and body condition and their genetic relationships with production traits were highly consistent across ages and the production cycle. As a result, the current practice by Sheep Genetics to treat adult weight as a single trait with repeat records is most likely sufficient. However, the inclusion of body condition within the Sheep Genetics evaluation has potential to assist in improving maternal performance, and the feed costs associated with maintaining ewe body condition.

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