Composite lamination method

A process was developed for preparing relatively thick composite laminate structure wherein thin layers of prepreg tapes are assembled, these thin layers are cut into strips that are partially cured, and stacked into the desired thickness with uncured prepreg disposed between each layer of strips. The formed laminate is finally cured and thereafter machined to the desired final dimensions

Composition of hog carcasses as influenced by heritable differences in rate and economy of gain

Much emphasis is placed on rate of gain in attempts to improve meat animals. However, little attention is given to composition of the carcass, except as it is indicated by the conformation of the live animals, largely because carcass data can be obtained only for progeny or relatives of the animals chosen for breeding purposes. Rate of gain and composition of carcasses are both determined by the growth rates of the constituent tissues. Hence, if there is more heritable variation in fat deposition, for example, than in growth of bone and muscle, selection for faster total gains would increase the rate of fat deposition more than it would the rate of bone and muscle growth, and fatter carcasses would result

Evaluation of selection in developing inbred lines of swine

Agricultural Experiment Stations of Illinois, Indiana, Iowa, Minnesota, Missouri, Nebraska, Oklahoma, and Wisconsin and U.S. Department of Agriculture cooperatingDigitized 2007 AES.Includes bibliographical references (pages 58-[60])

Performance of Booroola Merino and Finnsheep crossbred lambs and ewes

Booroola Merino (B, n= 18) and Finnsheep (F, n =31) rams were mated to F ewes and C3 ewes (1/2 Columbia, 1/4 Suffolk, 1/4 Hampshire). Progeny of these matings were evaluated for performance traits including ewe reproduction through 3 years of age. Averaged over dam breeds, there was no significant difference between B and F sires for conception rate (CR), litter size (LS) at birth or weaning or for lamb mortality to weaning. The difference among sire breeds was not large or significant for birth weight but F sired lambs were significantly heavier than B sired lambs at 63 and 147 days of age. Relative to F sired lambs, B sired lambs had a higher dressing percentage and less fat at the 12th rib but equal estimated percentage kidney fat. A significantly smaller percentage of B-C3 than F, F-C3 or B-F ewe lambs reached puberty by the end of their first breeding season. Ovulation rate at first mating was higher but embryo survival rate tended to be lower for B sired ewes than for F sired ewes. At 2 years of age, B sired ewes produced about 1 kg more wool than F sired ewes. With the exception of the very poor CR of B-C3 ewes at first parity, the differences between the four ewe genotypes were not large or significant for CR at first, second and third parity. The difference between B and F sired ewes in LS at birth was not significant at first parity but B sired ewes were more prolific at second and third parities. However, differences in lamb mortality reduced, and in some cases removed, the differences in LS by weaning time. Relative use of these breeds in commercial U.S. production schemes is discussed

Influence of heterosis and plane of nutrition on rate and economy of gains, digestion and carcass composition of pigs

This report includes much of the material presented by senior author as a dissertation for the Doctor of Philosophy degree in August, 1951--P. [3].Digitized 2007 AES.Includes bibliographical references (pages 41-42)

Components of performance in selecting for heterosis in swine

This bulletin is a report on Animal Husbandry Department project number 39 entitled 'Swine Improvement'--P. 6."This report includes much of the material presented by the senior author as a dissertation for the Doctor of Philosophy degree in July, 1952"--P. [7].Digitized 2007 AES.Includes bibliographical references (pages 67-68)

SIMULATION OF BREED AND CROSSBREEDING EFFECTS ON COSTS OF PORK PRODUCTION

A bio-economic model of swine production was used to simulate expected performance effects of breeds in alternative breeding systems on total costs/100 kg of live weight (EWW) or/l00 kg lean (ELW) for marketing at 100 kg live weight and on costs/100 kg lean for marketing at mean 185-d weight (ELA). Effects of heterosis and of six U.S. breeds were simulated for integrated industry purebred (P), two-breed specific (2S), backcross (2B) and rotation cross (2R), and three-breed specific (3S) and rotation cross (3R) breeding systems. Traits considered were age at puberty (-PUB), conception rate (CR), litter size born alive (NBA), preweaning viability (VIAB), milk production (MILK), age at 100 kg live weight (-DAYS) and empty body fat percentage (-FAT). Cost reductions from crossbreeding systems were greater for ELA than for ELW or EWW, ranging from -3 to -5% for 2S, -6 to -7% for 2B and 2R, and -7 to -9% for 3S and 3R. Reductions in nonfeed costs were much greater than those in feed costs for EWW and ELW (-4 to -12% vs -2 to -4%), and especially for ELA (-9 to -17% vs -1 to -2%). Order of maternal trait importance in ranking breeds was NBA, VIAB, CR, MILK and -PUB for P, 2R and 3R systems and as maternal breeds in 2S and 3S systems. For cost of lean, -FAT was as important as NBA in all except maternal breed roles. For ELA, -DAYS was important in all breed roles, but not for EWW and ELW, especially in maternal breed roles. In ranking paternal breeds for use in 2S and 3S systems, the important traits were only VIAB for EWW, VIAB and -FAT for ELW, but VIAB,-FAT and -DAYS for ELA. Existing breeds ranked differently as paternal breeds than as maternal or general purpose breeds. Complementary paternal-maternal effects permitted greater cost reductions from best 3S (-7 to -10%) than from best 3R (-6 to -8%) breed combinations. Maternal breeds in crosses benefited from superiority in components of both sow and pig performance

Biological Efficiency Differences Among \u3ci\u3eBos taurus\u3c/i\u3e x \u3ci\u3eBos taurus\u3c/i\u3e and \u3ci\u3eBos indicus\u3c/i\u3e x \u3ci\u3eBos taurus\u3c/i\u3e F\u3csub\u3e1\u3c/sub\u3e-Cross Cows

Matching germplasm to resources through designed crossbreeding programs can contribute to optimum beef production efficiency. This is particularly true in light of the wide diversity of environmental conditions encountered by beef producers in the U.S. This approach requires considerable knowledge about genetic diversity among breeds in components of performance and furthermore how those components interact to influence life-cycle efficiency in the production setting. It was largely this identified need, coupled with the importation of a number of new breeds from continental Europe, that gave impetus for the establishment of the Germplasm Evaluation (GPE) Program. In Cycles I and II of the GPE program, increases in cow output associated with higher breed potential for growth rate and milk production were largely offset by equivalent or greater increases in feed requirements for maintenance and lactation. Additionally, in Cycle III, output of calf weaned per cow in the breeding herd was high for Bos indicus x Bos taurus crosses relative to Bos taurus crosses. More information is needed to evaluate F1 cross of Bos taurus versus Bos indicus x Bos taurus sources of germplasm. Therefore, this study was conducted to: 1) estimate input/output components, and 2) estimate life-cycle efficiency of Cycle III breeds representing these types of F1 cross females

Influence of inbreeding, age and growth rate of sows on sexual maturity, rate of ovulation, fertilization and embryonic survival

This report includes most of the material presented by the senior author as a Doctoral dissertation--P. [3].Digitized 2007 AES.Includes bibliographical references (pages 39-40)

Reproductive development and performance of inbred and crossbred boars

This report includes much of the material presented by the senior author as a doctoral dissertation--P. [3].Digitized 2007 AES.Includes bibliographical references (page 56)