scholarly journals Challenges and adaptive strategies in pig breeding from the aspect of heat stress and heat tolerance

2020 ◽  
Vol 24 (1) ◽  
pp. 1-13
Author(s):  
István Nagy ◽  
György Kövér ◽  
Zsolt Gerencsér ◽  
Gabriella Szász

Authors summarized the results of the last three decades’ relevant literature examining the temperature effects on the various growth, reproductive and carcass traits in pigs. The ideal period of temperature measurement and the different methodologies characterizing temperature effects were summarized. The aspects of genotype environment interaction for the measured traits under hot and temperate conditions were also presented. Finally the possibilities of direct genetic selection for heat tolerance and its possible selection criteria traits were also discussed.

2016 ◽  
Vol 7 (2) ◽  
pp. 218-222 ◽  
Author(s):  
M. J. Carabaño

Exposure of livestock to high heat loads negatively affects animal’s productivity. Genetic selection for heat tolerance using quantitative approaches has been developed by making use of the milk recording information merged with the meteorological information in the test date. The main conclusions of the studies following this approach have been that there is genetic variability in the response to heat stress (HS), that a genotype by environment interaction between thermal comfort and HS conditions exists and that there is a genetic antagonism between HS tolerance and high milk production. This approach has the advantage of adding no extra costs to the existing milk recording schemes, but it has some disadvantages. Current milk recording information does not seem to fully capture the productive response to high heat loads. Moreover, the antagonism between heat tolerance and high milk production may offset the benefits of selection for this trait if heat-tolerant animals are less productive. The use of new tools from phenomics, genomics and transcriptomics can help in achieving an accurate selection of heat-tolerant animals without damaging progress in milk production. New phenotypes for this selection are measure of body temperature and respiration rates together with measures of indicators of heat tolerance in milk, through the use of mid IR spectroscopy. The use of commercial DNA chips to perform genome wide association studies or comparison of whole genome DNA sequence of animals of heat adapted and temperate climate breeds could also provide useful genomic information. Finally, RNA sequencing together with the recent discovery of the possibility to use the milk transcriptome instead of tissue biopsies could help to discover differentially expressed genes under HS and thermoneutrality. The existence of powerful tools to achieve better phenotypes to identify tolerantv. susceptible animals and to gain insights about the genetic mechanisms underlying HS response to be able to disentangle the genetic puzzle of heat tolerance may make possible the selection of heat-tolerant and still productive animals.


1986 ◽  
Vol 43 (2) ◽  
pp. 293-301 ◽  
Author(s):  
Carol Woolliams ◽  
N. F. Suttle ◽  
J. A. Woolliams ◽  
D. G. Jones ◽  
G. Wiener

ABSTRACTMortality and its causes were studied during two consecutive years in a total of 934 lambs. The lambs were from two lines of sheep genetically selected for low (L) and high (H) concentrations of copper (Cu) in plasma within an interbred Scottish Blackface × Welsh Mountain population and from unselected Scottish Blackface (B) and Welsh Mountain (W) breeds. The lambs grazed improved hill pastures. Half of the lambs in each line or breed were given an oral Cu supplement by 7·5 weeks of age.Mortality from birth to 24 weeks in H was less than half that in L; mean proportional mortalities were L 0·28, H 0·12, B 0·37 and W 0·07, with a similar distribution in each year. Swayback accounted proportionately for 0·26 deaths in year 1, but proportionately for only 0·02 in year 2. The majority of other losses involved a variety of microbial infections.Genetic type (W < H < L < B) was a major determinant of, and Cu supplementation a protection against, swayback and non-swayback losses. For non-swayback losses L lambs were about twice (P < 0·01) and B lambs about four times (P < 0·001) more vulnerable than H and W lambs respectively. Unsupplemented lambs were more than twice as vulnerable to non-swayback causes of death in the 1st year (P < 0·05) and four times as vulnerable in the 2nd year (P < 0·01) as were Cu-supplemented lambs. There were no cases of swayback in supplemented lambs even though Cu treatment was in some lambs as late as 7·5 weeks after birth.Such marked differences in mortality rate, particularly between the selected lines, had not been apparent in the 5 years preceding pasture improvement, suggesting a genotype × environment interaction affecting survival.The results provide the first definitive evidence that decreased resistance to infection is a clinical consequence of ovine Cu deficiency in the field, amenable to control by Cu treatment and genetic selection.


2012 ◽  
Vol 40 (2) ◽  
pp. 267-276 ◽  
Author(s):  
S. Sareen ◽  
R. Munjal ◽  
N. Singh ◽  
B. Singh ◽  
R. Verma ◽  
...  

1980 ◽  
Vol 30 (3) ◽  
pp. 327-340 ◽  
Author(s):  
N. Tilakaratne ◽  
J. C. Alliston ◽  
W. R. Carr ◽  
R. B. Land ◽  
T. J. Osmond

ABSTRACTThe use of variation in metabolism to predict genetic merit for milk production was studied using 42 Friesian calves: 11 ♀♀, 10 ♂♂ were the offspring of four bulls with high (H), and 11 ♀♀, 10 ♂♂ of four with low (L) improved contemporary comparison (ICC) values (mean = + 402 kg and − 276 kg respectively). The animals were 14 or 15 weeks of age at the start of the study and treated similarly throughout.Blood samples were collected: I—in relation to feeding; II—at set intervals; III—during a 44-h fast; and IV—following the sudden introduction of an energy metabolite (sodium propionate), and then refeeding. Plasma concentrations of β-hydroxybutyrate, glucose, urea, free fatty acids, total proteins and albumin were measured in all samples.Blood characteristics apparently differed among animals, particularly protein and urea (repeatability 0·74 and 0·62 respectively).The progeny of high ICC bulls had lower levels of urea during fasting (H = 4·70, L = 5·62P< 0·05) but higher levels of free fatty acids (H = 578, L = 492 μ equivalents/l;P< 0·05). There was a small difference in total protein (H = 69·7, L = 66·8 g/l,P< 0·05) but the other metabolites showed no significant ICC group difference.In general, sex of the animal did not influence the metabolites.Results suggest that calves with different potentials for milk production vary in aspects of energy and nitrogen metabolism; the possibility of using these as criteria for genetic selection for milk production is discussed.


2019 ◽  
Vol 49 (2) ◽  
pp. 128-133 ◽  
Author(s):  
Mari Suontama ◽  
Yongjun Li ◽  
Charlie B. Low ◽  
Heidi S. Dungey

Progeny testing of resistance to needle loss caused by Cyclaneusma minus (cyclaneusma needle cast) has been included in the needle disease resistance strategy of Pinus radiata D. Don in New Zealand since the late 1970s. Data on progeny trials, two in the North Island of New Zealand and one in Tasmania, Australia, were available to estimate heritability between trait genetic correlations and genotype × environment interaction. Resistance to cyclaneusma needle cast had moderate estimates of heritability (0.25 to 0.46) at all sites. Genetic correlations between the assessed traits indicated that selection for faster early growth, i.e., tree height at age 4 years and diameter at breast height at age 6 years, favours trees that are prone to Cyclaneusma infection, while a favourable genetic association between resistance to cyclaneusma needle cast and productivity was evident at a later assessment at age 9 years. No significant genotype × environment interaction was found for resistance to cyclaneusma needle cast; however, stability of genotypes across a wider range of environments and with a high genetic connectedness requires more research. Considerable genetic improvement can be achieved for resistance to cyclaneusma needle cast and indirect selection for the trait should be pursued by selecting for productivity and culling susceptible genotypes from breeding.


Genetics ◽  
1984 ◽  
Vol 108 (2) ◽  
pp. 409-424
Author(s):  
Fred B Schnee ◽  
James N Thompson

ABSTRACT The chromosomal architecture of genotype × environment interactions was investigated in lines of Drosophila melanogaster selected for increased or decreased sternopleural bristle number at 18°, 25° and 29°. In general, interactions were found to have a stabilizing effect upon the bristle phenotype, in the sense that the genotype × environment interaction tended to increase bristle number under conditions in which temperature alone reduced bristle number and vice versa. The polygenic modifiers of mean bristle number were often separable from modifiers of the response to temperature both at the chromosomal level and intrachromosomally. In one of the low selection lines, a temperature-dependent polygenic locus was mapped on chromosome 3. It is suggested that genotype × environment interactions be thought of in terms of conditional polygenic expression. Such conditionality may be one of the ways in which polygenic variation is maintained in a population in the face of selection for an optimum phenotype.


1992 ◽  
Vol 117 (5) ◽  
pp. 867-870 ◽  
Author(s):  
Linda Wessel-Beaver ◽  
J.W. Scott

Heritabilities (h2) and genetic correlations between percent fruit set, yield, and fruit weight were estimated from one summer planting each in Florida and Puerto Rico of 100 S, tomato (Lycopersicon esculentum Mill.) families from a synthetic population. Single-location h2 was high for all traits. Across-locations h2 was low for yield, intermediate for fruit set, and high for fruit weight. Genotype × environment interaction (G × E) was 1) the only significant component of variance for yield, 2) somewhat important for fruit set, and 3) not an important variance component for fruit weight. The greater importance of genetic variance compared to G × E variance explains why across-location heritabilities for fruit weight and fruit set were high. Genetic correlations between fruit set and weight were strongly negative, while those between yield and set were large and positive. Yields under high temperatures may increase with selection for fruit set, but a reduction in fruit weight would be expected in this population and those with similar genetic correlations.


Euphytica ◽  
2016 ◽  
Vol 209 (1) ◽  
pp. 261-280 ◽  
Author(s):  
Maria I. Andrade ◽  
Abdul Naico ◽  
José Ricardo ◽  
Raúl Eyzaguirre ◽  
Godwill S. Makunde ◽  
...  

1964 ◽  
Vol 5 (3) ◽  
pp. 335-340 ◽  
Author(s):  
J. F. Kidwell ◽  
A. E. Freeman ◽  
L. H. Haverland ◽  
G. M. H. Rolfes

An experiment was conducted with the flour beetle, Tribolium castaneum to investigate genotype-environment interaction. Ninety-two matings of one male and three females were made at random from a large panmictic population. The females were transferred to individual containers after 4 days. Six daughters were randomly selected from each sire–dam pair and individually mated to unrelated males. Three of the six were placed in an incubator (33·3°C., 45% relative humidity) and three in a cabinet at room conditions (22·2–26·7°C., 30–35% relative humidity) and allowed to produce eggs during a 3-day period. Progeny were counted as pupae and larvae. The traits studied were number of pupae and number of pupae plus number of larvae. A transformation to (X +1)½ was required. A conventional least-squares model was employed, and a large environmental effect was observed. In the incubator the mean number of pupae was 13·4 and of pupae + larvae was 20·1 while the corresponding figures for room conditions were 3·3 and 9·2. Genotype-environment interaction accounted for 3·7 to 6·7% of the total variance for (pupae + 1)½ and 2·1 to 8·3% for (pupae + larvae+ 1)½. Heritability of the traits was essentially the same in both environments. The interaction was due to an increasing difference between environments in production associated with increasing breeding values of the sire, and to small changes in rank of breeding values on the two environments. As a result of the interaction, selection in one environment for production on the other would be expected to be only 71 to 72% as effective as direct selection for (pupae + 1)½ and 62 to 86% for (pupae + larvae + 1)½ even though the fraction of the total variance attributed to genotype-environmental interaction was less than 10%.


2001 ◽  
Vol 31 (3) ◽  
pp. 496-511 ◽  
Author(s):  
G R Hodge ◽  
W S Dvorak

A total of 23 provenances or sources of Pinus caribaea var. hondurensis (Sénécl) Barr. et Golf. were tested in 48 provenance–progeny trials in Colombia, Brazil, and Venezuela. In Brazil and Venezuela, 8-year heights were approximately 12 m, while in Colombia, mean 8-year height was less than 8 m. The growth rates of the unimproved material correspond approximately to volumes of 14–15 m3·ha–1·year–1 of wood on sites in Brazil and Venezuela, and 4–5 m3·ha–1·year–1 in Colombia. Provenances had similar growth rankings in the different countries, with a type-B provenance correlation of 0.63. The best native provenances were Limón and Guanaja, Honduras. Improved first-generation sources from Queensland, Australia and Zululand, South Africa, were 5–12% better than the mean of the unimproved provenances, depending on country where planted. Mean single-site heritability for volume growth is approximately 0.18. Potential genetic gain for volume at 8 years from selection within provenance is around 30%. Foxtailing is also under moderate genetic control with heritability around 0.15. Genotype × environment interaction for volume growth is generally higher for tests located in different countries than in the same countries. Selection for age-8 volume using age-5 data would be 93% as effective as selection at age 8.


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