TY - JOUR TI - OPPORTUNITIES AND RESPONSIBILITIES OF AGRICULTURAL ECONOMISTS - COLLEGES OF AGRICULTURE AU - LEGATES, JE T2 - AMERICAN JOURNAL OF AGRICULTURAL ECONOMICS AB - American Journal of Agricultural EconomicsVolume 57, Issue 5 p. 782-784 General Session Opportunities and Responsibilities of Agricultural Economists: Colleges of Agriculture J. E. Legates, J. E. Legates the dean of the School of Agriculture and Life Sciences North Carolina State UniversitySearch for more papers by this author J. E. Legates, J. E. Legates the dean of the School of Agriculture and Life Sciences North Carolina State UniversitySearch for more papers by this author First published: 01 December 1975 https://doi.org/10.2307/1239077Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume57, Issue5December 1975Pages 782-784 RelatedInformation DA - 1975/// PY - 1975/// DO - 10.2307/1239077 VL - 57 IS - 5 SP - 782-784 SN - 0002-9092 ER - TY - JOUR TI - EFFECTS OF SELECTION FOR POSTWEANING GAIN ON TESTICULAR FUNCTION IN MICE AU - JOHNSON, BH AU - EISEN, EJ T2 - CANADIAN JOURNAL OF GENETICS AND CYTOLOGY AB - Changes in testicular and epididymal function and selected endocrine organ size were examined in a line of mice selected for rapid postweaning gain (M16) and in reciprocal crosses with an unselected pedigree control line (ICR). The larger body weight of the M16 line was accompanied by larger testes, epididymides, seminal vesicle, pituitary, thyroid and adrenal weights (P smaller than .01) although the testes, epididymides, seminal vesicle and adrenal weights of M16 mice, expressed per gram body weight, actually decreased (P smaller than .01) relative to the ICR line. Testicular and epididymal sperm reserves were higher in M16 mice but the difference was not significant. However, when adjusted for gland size, testicular and epididymal sperm reserves were lower in the M16 line (P smaller than .01). Absolute and relative weights of testes, epididymides and pituitary were larger (P smaller than .01) in M16 male times ICR female crosses than in ICR male times M16 female crosses. Although testicular and epididymal sperm reserves were higher in M16 male times ICR female males the reciprocal difference was significant only for testicular sperm (P smaller than .05). Heterotic effects were significant for both absolute and relative weights of testes, epididymides (P smaller than.01), pituitary (P smaller than .05) and relative weight of siminal vesicles (P smaller than .05). Although percent heterosis was 8.5 for testicular and epididymal sperm reserves, significant heterotic effects were found only for epididymal sperm (P smaller than .05). DA - 1975/// PY - 1975/// DO - 10.1139/g75-010 VL - 17 IS - 1 SP - 93-104 SN - 0008-4093 ER - TY - JOUR TI - RELATIONS BETWEEN SIRE SUMMARIES OF FIRST AND SECOND LACTATIONS AU - TOMASZEWSKI, MA AU - MCDANIEL, BT AU - NORMAN, HD AU - DICKINSON, FN T2 - JOURNAL OF DAIRY SCIENCE AB - Abstract Sire summaries of one or more progeny in first lactations in each of 20 or more herds were compared to progeny in second lactations of the same 133 Holstein bulls. Progeny in second lactations were also in 20 or more herds, but these herds were completely different from those having first lactation progeny. Since it is unlikely that any of the progeny were common to both the first and second lactation summaries, associations between summaries should estimate genetic associations. Progeny were compared to either contemporaries in first or second lactation or herdmates of all ages. Correlations between summaries for first and second lactations for deviations of milk yield ranged from .56 to .62 compared to an expected correlation for deviations from herdmates of .66. Correlations were highest when progeny were deviated from herdmates of all ages. A progeny test on first lactation milk is about 85% as accurate in predicting second lactation performance as a progeny test on second lactations. Progeny tests for milk yield from only progeny in first lactation are sufficient for most objectives of selection. DA - 1975/// PY - 1975/// DO - 10.3168/jds.S0022-0302(75)84527-9 VL - 58 IS - 1 SP - 116-121 SN - 0022-0302 ER - TY - JOUR TI - Population size and selection intensity effects on long-term selection response in mice AU - Eisen, E. J. T2 - Genetics DA - 1975/// PY - 1975/// VL - 79 IS - 2 SP - 305 ER - TY - JOUR TI - INFLUENCE OF MALES PRESENCE ON SEXUAL-MATURATION, GROWTH AND FEED EFFICIENCY OF FEMALE MICE AU - EISEN, EJ T2 - JOURNAL OF ANIMAL SCIENCE DA - 1975/// PY - 1975/// DO - 10.2527/jas1975.405816x VL - 40 IS - 5 SP - 816-825 SN - 0021-8812 ER - TY - JOUR TI - ASSESSMENT OF FIELD MEASURES OF MILKING RATE AU - TOMASZEWSKI, MA AU - HARGROVE, GL AU - LEGATES, JE T2 - JOURNAL OF DAIRY SCIENCE AB - Abstract Several measures of milking rate were taken twice per lactation during 1457 Holstein lactations in five herds. These were taken to determine which variable would be most practical as a field measure of milking rate. Milking rates were estimated by peak flow which has been taken as the standard measure for milking rate, average flow, percent of milk produced in the first 2min of machine milking, and the amount of milk produced through the 1st min, first 1.5min, and first 2min of milking. Variables constructed from possible differences among these last three variables were also assessed. A measurement solely used to indicate rate should be obtainable before the 3rd min of milking. If rate were measured after that time, an increasingly larger number of cows would have completed their milking, and their records would not be considered in determining rate of flow. The percent of milk yielded in the first 2min of machine milking had high phenotypic (.90) and genetic (1.0) correlations with peak flow. Percent 2min milk was as repeatable within lactations and as heritable as peak flow. These four properties plus the ease with which percent 2min milk was obtained indicated that percent 2min milk was an adequate field measure of milking rate. DA - 1975/// PY - 1975/// DO - 10.3168/jds.S0022-0302(75)84605-4 VL - 58 IS - 4 SP - 545-550 SN - 1525-3198 ER - TY - JOUR TI - UTERINE CAPACITY AND PROGESTIN LEVELS IN SUPER-INDUCTED GILTS AU - RAMPACEK, GR AU - ROBISON, OW AU - ULBERG, LC T2 - JOURNAL OF ANIMAL SCIENCE AB - Embryos were transferred from crossbred donor gilts to eight Duroc, nine Yorkshire and eight crossbred recipient gilts to determine differences in uterine capacity among genetic groups. Donor gilts were injected IM with 750 IU of PMSG on Day 16 (onset of estrus = Day 0). Donors and recipients were mated 12 and 24 hr after onset of estrus. Embryos were recovered on Day 4 and were deposited into the uterus. Peripheral blood was collected from all recipients on Day 13 and Day 20 of gestation. Plasma progestin levels were measured, using radioimmunoassay, for all recipient gilts to determine the correlation between progestin levels and uterine capacity. Recipients were slaughtered on Day 25 ± 2. The average number of corpora lutea and embryos deposited in the Duroc, Yorkshire and crossbred recipients were, respectively: 14.8, 13.1; 12.9, 13.3; 13.9, 15.6. The average number of normal embryos on Day 25 in the Duroc, Yorkshire and crossbred recipients was, respectively: 16.8 ± 1.8; 18.1 ± 1.3; 20.8 ± 1.6. Although nonsignificant, (P>.05) there was a difference of four normal embryos between the Duroc and crossbred gilts. The average progestin concentrations (ng/ml plasma) on Day 13 and Day 20 for the Duroc, Yorkshire and crossbred recipients were, respectively: 22.8 ± 2.9, 21.7 ± 2.0; 29.7 ± 2.3, 19.2 ± 1.2; 24.6 ± 1.3, 23.9 ± 3.0. There were no differences (P>.05) in progestin levels among genetic groups. There were, however, significant (P<.05) correlations between Day 13 progestin level and number of live embryos at Day 25 for the crossbred recipients (.67) and for the Yorkshire recipients (.65). These results indicate that progesterone levels on or near Day 13 of gestation may be associated with early gestation uterine capacity. DA - 1975/// PY - 1975/// DO - 10.2527/jas1975.412564x VL - 41 IS - 2 SP - 564-567 SN - 0021-8812 ER - TY - JOUR TI - MULTIPLE-REGRESSION MODEL FOR NET INCOME ESTIMATES FROM 100-SOW PRODUCTION UNITS AU - ALSMEYER, WL AU - CLAWSON, AJ AU - MANSON, AR AU - LINNERUD, AC T2 - JOURNAL OF ANIMAL SCIENCE AB - Two regression equations are presented for evaluating the effects of market conditions and production efficiency on annual net income from 100-sow production units. The linear model can be used to evaluate changes in net income associated with varying one of the 11 possible input variables. The larger model can be used for the evaluation of changes in any one or all of the 11 input variables simultaneously, and should be used when two or more cost or production factors are used as input variables away from their central point. An example is presented showing the insensitivity of a complete production system to changes in the hog: corn ratio and a similar example considers the effect on annual net income of variations in market weight of live hogs. DA - 1975/// PY - 1975/// DO - 10.2527/jas1975.4016 VL - 40 IS - 1 SP - 6-12 SN - 0021-8812 ER -