Progeny testing sires selected by independent culling levels for below-average birth weight and high yearling weight or by mass selection for high yearling weight.

In the epidemic years 1965 and 1966, field ratings confirmed that southern strains of smooth bromegrass, Bromus inermis Leyss, were generally less susceptible to leaf spot caused by Selenophoma bromigena (Sacc.) Sprague & A. G. Johnson than northern strains. The northern/southern hybrid S-6733, developed by mass selection and progeny testing, was found to resist S. bromigena at least as well as the southern strains Lincoln and Redpatch, and better than the southern Saratoga. It was found possible to improve resistance of the susceptible northern strain Carlton by mass selection. Northern strains probably do not have as great a potential for improvement in disease resistance as southern strains or hybrids.

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MASS SELECTION FOR POST-WEANING GROWTH IN SWINE. V. CORRELATED RESPONSE OF REPRODUCTIVE TRAITS AND PRE-WEANING GROWTH

Canadian Journal of Animal Science ◽

10.4141/cjas76-096 ◽

1976 ◽

Vol 56 (4) ◽

pp. 791-801

Author(s):

I. GARNETT ◽

G. W. RAHNEFELD

Keyword(s):

Birth Weight ◽

Average Daily Gain ◽

Reproductive Traits ◽

Correlated Response ◽

Mass Selection ◽

Gestation Length ◽

Control Line ◽

Weaning Weight ◽

Selection For ◽

Daily Gain

Female reproductive performance and pre-weaning survival and growth were examined in a population of swine over 11 generations of selection for post-weaning average daily gain (ADG). Three separate breeding groups were used: (1) a Lacombe (L) line selected each generation for ADG, (2) a Yorkshire control (Y) line, and (3) a crossbred Lacombe × Yorkshire group (LY) generated each generation from the L and Y lines. Breeding group differences were evident for litter size, perinatal mortality, pre-weaning mortality, gestation length, birth weight, pre-weaning average daily gain (PreADG) and weaning weight. Selection did not affect number born, number born alive, number weaned or birth weight. When the values for the L line were expressed as a deviation from the control, pre-weaning mortality showed an increase. The increase appeared to be due to a decrease in the control rather than an increase in the L line. Gestation length showed a negative response to selection. As in the case of pre-weaning mortality, the response appeared to be a reflection of the instability of the control line. Genetic gains in PreADG of 0.004 kg/day/generation were realized in both the L line and LY group. Correspondingly, responses of 0.18 and 0.19 kg/generation were realized for weaning weight in the L line and LY group.

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Short-term Progeny Tests and Second Generation Breeding in Slash Pine

Canadian Journal of Forest Research ◽

10.1139/x73-024 ◽

1973 ◽

Vol 3 (2) ◽

pp. 165-169

Author(s):

E. C. Franklin ◽

A. E. Squillace

Keyword(s):

First Generation ◽

Second Generation ◽

Slash Pine ◽

Mass Selection ◽

Progeny Testing ◽

Family Selection ◽

Short Term ◽

Major Disadvantage ◽

Selection For ◽

Almost All

Progeny testing is the most widely used method for intensive genetic evaluation of selected forest trees, but its major disadvantage is the length of time needed to get results. To circumvent this problem in selection for a multiproduct strain of slash pine (Pinuselliottii Engelm.), a system for short-term (3-year) progeny testing was developed. Oleoresin yields of selected second-generation 19-year-old parent trees were compared with yields of their 3-year-old offspring. Both parents and offspring showed little variation and a low offspring–parent correlation (r = 0.18), but other traits based on the same parent trees when they were 25 years old and their 3-year-old offspring showed relatively large amounts of variation and moderate to strong offspring-parent correlations: height, r =.56; volume, r = 0.43; turpentine, r = 0.71; ethanol–benzene extractives, r = 0.38; specific gravity, r = 0.43; moisture content, r = 0.34. Thus, indications are that additional gains could be made in the first generation by selecting among parent trees on a progeny performance basis in all traits except oleoresin yield. Original mass selection for oleoresin yield achieved gains of 100% improvement and apparently exploited almost all of the genetic variation in the base population. In second generation selection, progeny testing will be used primarily in screening for fusiform rust resistance. Between-family plus within-family selection will be used for other traits.

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19 Mature size and other trait differences in cows selected for calving ease and growth

Journal of Animal Science ◽

10.1093/jas/skaa278.041 ◽

2020 ◽

Vol 98 (Supplement_4) ◽

pp. 22-23

Author(s):

Gary L Bennett ◽

John W Keele ◽

R Mark Thallman ◽

Warren M Snelling ◽

Harvey C Freetly ◽

...

Keyword(s):

Birth Weight ◽

Equal Opportunity ◽

Growth Curves ◽

Average Birth Weight ◽

Calving Ease ◽

Calf Survival ◽

Selection For ◽

And Control ◽

Calving Difficulty ◽

Mature Size

Abstract Cows selected for heifer calving ease and yearling weight might also show changes in other important traits. Cattle from select and control lines within 7 populations were selected for reduced heifer calving difficulty EPD (select) or for average birth weight EPD (control) and for identical yearling weight EPD (select and control). Heifers randomly sampled within sire and born in the 4th and 5th of 7 years of selection were retained until 6 years of age with culling for once open and health, but not for other performance. Both lines were bred to the same bulls for calves born during the 3 years post-selection. Select line heifers were 7% lighter (-2.6 ± 0.5 kg, P < 0.01) at birth and not different at weaning (0.2 ± 1.5 kg) or yearling ages (-2.1 ± 2.7 kg). Select cow mature weights estimated by Brody growth curves were 5.2% lighter (-32.9 ± 3.7 kg, P < 0.01) and heights were 2.2% shorter (-3.0 ± 0.7 cm, P < 0.01) than controls. Calf weaning weights were not different. Interactions between 1st calving select (bred to select bulls) and control heifers (bred to control bulls) vs. older cows (all bred to the same bulls) were significant for survival (P < 0.01) and calving assistance (P = 0.03). Select line heifers increased calf survival (86.8% vs. 70.9%) and had decreased calving assistance (16.4% vs. 39.3%), but differences in cows for these traits were negligible. Calves born per select cow exposed exceeded those born per control cow only for 2nd calving (7.1%, P = 0.04), possibly due to reduced calving difficulty as heifers. Selection for calving ease and yearling weight resulted in cows with smaller mature size and similar or better calving ease, calf survival, and calf weaning weight. USDA is an equal opportunity provider and employer.

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The Stomach Capacity is Reduced in Intrauterine Growth Restricted Piglets Compared to Normal Piglets

Animals ◽

10.3390/ani10081291 ◽

2020 ◽

Vol 10 (8) ◽

pp. 1291

Author(s):

Julie C. Lynegaard ◽

Janni Hales ◽

Marlene N. Nielsen ◽

Christian F. Hansen ◽

Charlotte Amdi

Keyword(s):

Birth Weight ◽

Intrauterine Growth Restriction ◽

Growth Restriction ◽

Empty Stomach ◽

Average Birth Weight ◽

Intrauterine Growth ◽

Newborn Piglets ◽

Selection For ◽

Head Morphology ◽

Stomach Weight

Selection for increased litter sizes have decreased the average birth weight of piglets and up to 30% of newborn piglets in Danish herds show signs of intrauterine growth restriction (IUGR). It has been reported that around 48% of liveborn piglets dying between birth and weaning have empty stomachs, and that IUGR piglets do not ingest the recommended amount of colostrum to survive. The aim of this study was to investigate how much colostrum could be administrated depending on whether they were IUGR compared to normal piglets. Seventy-two piglets within 24 h of farrowing were classified as either IUGR or normal based on their head morphology. Stomach weight, length and capacity were measured along with bodyweight (BW). The results displayed a decreased BW, empty stomach weight and capacity in IUGR piglets, as well as a decreased relative stomach capacity in IUGR compared with normal piglets. In conclusion, birth weight is not the only factor influencing stomach capacity, and IUGR piglets have a smaller stomach capacity compared with normal piglets. It is estimated that IUGR piglets have the capacity to be given a bolus of 25 mL per kg/BW, whereas a normal piglet have a higher capacity (30 mL per kg/BW).

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Selection for economic characters in Australian Merino sheep. II. Relative efficiency of certain aids to selection.

Australian Journal of Agricultural Research ◽

10.1071/ar9520409 ◽

1952 ◽

Vol 3 (4) ◽

pp. 409 ◽

Cited By ~ 6

Author(s):

FHW Morley

Keyword(s):

Artificial Insemination ◽

Relative Efficiency ◽

Mass Selection ◽

Progeny Testing ◽

Merino Sheep ◽

Selection For ◽

The Cost ◽

Australian Merino

Theoretical consequences of the use of progeny testing, sib testing, and mass selection are examined in a flock of 1,000 ewes producing 700 progeny of breeding age each year. Selection based on a combination of individual merit and merit of half-sibs should result in approximately the same annual improvement as that achieved by optimum use of progeny-tested sires. In large flocks extensive use of outstanding sires by artificial insemination may increase progress for traits with heritability of about 0.3 by a factor of about 1.2 as compared with mass selection. The advantages to be gained by progeny testing and artificial insemination may be outweighed by the dangers of inbreeding, and the cost involved would have to be considered. As most of these advantages should be achieved by combination or even by mass selection, which avoid inbreeding and much of the cost, progeny testing with wide use of progeny-tested sires is unlikely to be the most economical road to flock improvement.

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