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Biomedical subjects

L D Young

Publications and source records attributed to L D Young.

At least 37 records · Page 2Linked to original sources

Racial differences in perceptions concerning hypertension and its consequences.

To investigate racial differences in hypertensive patients' understanding of their disorder, we administered a questionnaire to 83 black and 260 white outpatients with the diagnosis of hypertension designated in their medical chart. No racial differences in systolic or diastolic blood pressure, age, or male/female ratio were observed. However, blacks were more likely than whites to identify renal failure as a consequence of hypertension, whereas whites were more likely to identify atherosclerosis. Blacks also were more likely than whites to accept higher diastolic blood pressures as normal (90 to 100 mm Hg versus 80 to 90 mm Hg). There was no correlation between knowledge and blood pressure. Our observations show that both racial groups are well educated about antihypertensive therapy as well as the consequences and complications of hypertension. Comprehensive treatment of hypertension should include educational strategies that are population-specific and that address ways to change disease-relevant behaviors, rather than merely identifying which behaviors to change.

Black or African American↗

Reproductive, endocrine, and organ weight differences of swine selected for high or low serum cholesterol.

Three generations of selection for 56-d blood cholesterol concentrations were used to establish low and high cholesterol lines of pigs in which cholesterol concentrations differed by 39% in the last generation. Litter size (number of fully formed pigs born per litter) diverged with each successive generation of selection and, at the third generation, litter size differed between the low and high line by two pigs (high line = 8.5 +/- .6; low line = 10.5 +/- .5; P < .05). A random selection of offspring (gilts, n = 109; boars, n = 46; barrows, n = 94) from the third generation and a control line maintained throughout the experiment were monitored for hormonal and anatomical relationships that might provide insight into the mechanisms that altered fecundity. Ovulation rate (number of corpora lutea) as determined on d 60 of pregnancy was increased in the low (n = 29) compared with the high cholesterol line (n = 38; 11.8 +/- .3 vs 9.8 +/- .3, respectively; P < .05), and litter size continued to be increased in the low cholesterol line (P < .05). No differences were noted between lines in kidney, ovarian, or total corpora lutea weight. Empty uterine weight and adrenal weight were increased in the high cholesterol line (P < .05) in randomly selected offspring of the third generation, and liver weight increased in the low line (P < .05). Associated with increased concentrations of cholesterol were increased serum concentrations of progesterone (gilts) and testosterone (boars) in the high cholesterol line (P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Glands↗

Comparison of Finnish Landrace and Romanov as prolific breeds in a terminal-sire crossbreeding system.

Targhee ewes lambing to Romanov vs Finnish Landrace rams gave birth to .22 more lambs (P = .02) and had .15 more lambs alive at weaning (P = .11) but did not rear more lambs. Finnish Landrace x Targhee (FT) and Romanov x Targhee (RT) lambs were similar for preweaning survival and for all growth and carcass traits studied. Romanov x Targhee ewes were 14.2 +/- 6.2 d younger (P = .02) at their first estrus and 12.1 +/- 2.8 d younger (P < .01) at their first lambing than FT ewes. The ovulation rate of RT ewes exceeded that of FT ewes by .35 (P < .01). Romanov x Targhee ewes gave birth to .42 more (P < .01) lambs per ewe lambing, had .39 more (P < .01) lambs alive at weaning per ewe lambing, and reared .15 more (P = .03) lambs per ewe lambing than FT ewes. Embryonic survival, adjusted for ovulation rate, was greater (P < .01) for RT (88.3 +/- 3.3%) than for FT (80.0 +/- 3.7%) ewes. Lamb survival was similar for the two F1 crosses, with or without adjustment for number of lambs born. Overall survival (the proportion of ova that resulted in weaned lambs) was greater (P = .02) for RT ewes (77.6 +/- 4.2%) than for FT ewes (67.5 +/- 4.7%), at the same ovulation rate. When ewes were credited with all the lambs they gave birth to, RT ewes produced 4.6 +/- 1.8 kg more (P < .01) weight of lamb at weaning.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Effect of sire and dam breed on copper status of fat lambs.

To determine the effect of breed on copper status of crossbred (F1) lambs, a study was conducted using 187 crossbred wether lambs. Wether lambs were progeny of five ram breeds (Dorset, Finnsheep, Montadale, Romanov, and Texel) and two ewe breeds (Rambouillet and a composite breed [1/2 Columbia, 1/4 Suffolk, 1/4 Hampshire]). Diets were adjusted to decrease crude protein twice during the experimental period, with analyzed copper levels for the three diets of 5.2, 4.4, and 3.6 ppm. All means were adjusted to a constant carcass weight of 27.265 kg using a covariate analysis. Least squares means of the liver copper concentration for sire breeds ranged from 307 to 458 micrograms/g on a DM basis. Romanov- (307 micrograms/g) and Finnsheep-sired (327 micrograms/g) lambs had the lowest liver copper concentration, whereas Montadale- (359 micrograms/g) and Dorset-sired (360 micrograms/g) lambs were intermediate and Texel-sired (458 micrograms/g) lambs were significantly higher compared with other lamb breeds. Least squares means for total liver copper for the five ram breeds ranged from 69 to 101 mg. Finnsheep- (69 mg), Romanov- (72 mg), and Montadale-sired (80 mg) lambs were lowest, Dorset-sired (85 mg) lambs were intermediate, and Texel-sired (101 mg) lambs were higher (P < .02) compared with other lamb breeds for total liver copper. Least squares means for serum copper ranged from .86 to 1.05 ppm. Levels of serum copper were similar for Montadale- (.86 ppm), Finnsheep- (.90 ppm), Texel- (.93 ppm), and Dorset-sired (.94 ppm) lambs and higher (P < .02) for Romanov-sired (1.05 ppm) lambs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

Milk cholesterol concentration in sows selected for three generations for high or low serum cholesterol.

Female crossbred swine (Chester White x Landrace x Large White x Yorkshire) selected for three generations for low (L, n = 24) or high (H, n = 26) serum cholesterol at 8 wk of age were milked at d 20 or 21 of their first lactation to measure cholesterol, fat, lactose, protein, and ash concentrations. A contemporary, unselected control (C) group from the same original population (third lactation, n = 7) was sampled concurrently. All sows were fed a standard gestation, then lactation, diet that contained no cholesterol or added fat (all plant, corn-soybean meal). Genetic selection for low or high serum cholesterol at 8 wk of age induced corresponding changes in milk cholesterol and fat concentration in the third generation of selection, but not in any other milk constituents. Milk cholesterol concentrations (milligrams/100 grams fresh weight) were L, 25.3 +/- 3.0; C, 35.7 +/- 8.0; and H, 41.4 +/- 6.9 (L < C < H, P < .01). Corresponding values for milk fat were 5.7 +/- 1.3, 7.2 +/- .8, and 7.0 +/- .8 mg (L < C = H, P < .01). Serum cholesterol concentrations at 8 wk of age were L, 66.1 +/- 8.1; C, 93.7 +/- 13.7; and H, 126.2 +/- 9.7 mg/dL (P < .01). Milk cholesterol concentration was significantly correlated with serum cholesterol (r = .782, P < .01) and milk fat (r = .36, P < .01). It seems that selecting swine for low or high serum cholesterol at 8 wk of age induced changes in lipid metabolism reflected in differences in milk cholesterol concentrations.

Animals↗

Direct and correlated responses to divergent selection for serum cholesterol concentration on day 56 in swine.

Divergent selection for serum cholesterol concentration on d 56 was practiced in a four-breed, composite population for three generations. High and Low lines, representing high and low levels of serum cholesterol, respectively, were each maintained with approximately 10 males and 25 females per generation. Pigs from a contemporary Control line were evaluated only in the last generation. In the last generation, mean serum cholesterol concentration was significantly different among lines (107.1, 85.6, and 65.5 mg/dL for High, Control, and Low lines, respectively). Realized heritability was .31, .33, and .31 for high, low, and divergent selection (SE = .03), respectively. Terminal evaluation indicated that average birth and weaning (28 d of age) weight was lower (P < .05) for Low pigs (1.25 and 6.25 kg, respectively) than for High pigs (1.43 and 7.10 kg, respectively) and was intermediate for Control pigs (1.34 and 6.53 kg, respectively). At 56 d of age, High (15.1 kg) and Control (13.5 kg) pigs were heavier (P < .05) than Low pigs (11.9 kg). However, pigs sampled after 56 d did not differ (P > .05) in average daily gain, 164-d weight, feed consumption, or feed efficiency. Serum cholesterol concentration at 165 d of age was significantly different among lines (110.1, 98.5, and 85.6 mg/dL for High, Control, and Low pigs, respectively), although differences were smaller than at 56 d of age. When slaughtered at approximately 106 kg (188 to 195 d of age), Low pigs had significantly shorter carcasses than High and Control pigs (77.5 vs 78.7 and 78.9 cm, respectively). Low pigs had significantly more fat at the first rib (5.70 vs 5.28 cm) than High pigs. Lines did not differ significantly for fat thickness at the last rib, last lumbar vertebrae or 10th rib, or for longissimus muscle area. At 60 d of gestation, ovulation rate, measured as number of corpora lutea, was lower (P < .05) for High (9.84 eggs) than for Low (11.79 eggs) or Control (11.17 eggs) gilts. Differences in ovulation rate were reflected in smaller but nonsignificant differences in number of fetuses (7.97, 9.00, and 8.55 fetuses for High, Low, and Control, respectively).

Analysis of Variance↗

Uterine function in Meishan pigs.

The Meishan pig provides a biological model with the genetic capacity to express a high prolificacy. This prolificacy can be partially attributed to a higher ovulation rate and a higher rate of prenatal survival at a given ovulation rate throughout gestation than in European breeds. Both early embryonic survival (factors inherent to the ovum and uterus, which occur before day 25 of gestation) and uterine capacity (factors inherent to uterine limitation, which occur from 30 days of gestation to parturition) may contribute to prenatal survival. Crossbreeding studies show that the prolificacy of Meishan pigs is primarily of maternal origin, but not whether the effects occur via the ovum, uterus or systemic factors. Although there have been few comparative studies on uterine function for prolific pigs, experiments relating to three general areas have been reported. During neonatal uterine development, endometrial gland development occurs shortly after birth in Meishan and European breeds. Tissue culture for 24 h showed that secretion of at least three uterine proteins (one identified as retinol-binding protein) increased in clear temporal association with development of the endometrial gland. The secretion of two additional proteins appears to change in a breed-specific manner. Although regulatory roles for uterine proteins remain to be defined, biochemical events associated with neonatal endometrial gland development may affect subsequent adult uterine function. During the time of maternal recognition of pregnancy or early gestation, reports suggest that uterine secretions are enhanced in Meishan pigs, which may partially explain their increased prolificacy. However, other studies show smaller embryo and placental weights at day 30 of gestation, suggesting that prolificacy of Meishan females is related to a maternal ability to control embryo/fetal and placental growth. During the later fetal period (uterine capacity) in European pigs, endometrial response to a crowded uterine environment is minimal, but the conceptus responds to a crowded uterine environment by altering placental function; similar experiments using Meishan pigs are in progress. Once the regulatory determinants of uterine function are understood, improvements can possibly be made in the reproductive efficiency of all swine.

Animals↗

Epidural clonidine treatment for refractory reflex sympathetic dystrophy.

BACKGROUND: Intraspinally administered alpha 2-adrenergic agonists may relieve pain in sympathetically maintained pain (SMP) syndromes, such as reflex sympathetically dystrophy (RSD), by spinal, peripheral, and central nervous system actions. This study examined analgesic efficacy and side effects of epidurally administered clonidine in patients with severe, refractory RSD. METHODS: Twenty-six patients with severe chronic pain consistent with RSD were studied in a randomized, blinded, placebo-controlled design. Cervical or lumbar epidural catheters were inserted for patients with upper or lower extremity RSD, respectively, and patients received, in random order on three consecutive days, epidural injection of clonidine, 300 or 700 micrograms, or placebo. Pain (by visual analog score (VAS) and McGill Pain Questionnaire), sedation, blood pressure, and heart rate were monitored at specified intervals for 6 h after injection. Patients who responded to clonidine, but not placebo, then entered a trial of open-label, continuous epidural infusion of clonidine (10-50 micrograms/h). RESULTS: Clonidine, but not placebo, caused pain relief, sedation, and decreased blood pressure and heart rate after bolus epidural injection. The smaller clonidine dose (300 micrograms), produced pain relief and decreases in blood pressure and heart rate similar to those of the 700 micrograms dose, but with less sedation. Epidural clonidine was infused for a mean of 43 days in 19 patients at a mean rate of 32 micrograms/h for sustained analgesia. CONCLUSIONS: Transdermal clonidine has been demonstrated to produce analgesia in the area surrounding its application site in patients with SMP. The current study indicates that extensive analgesia may be obtained by epidural administration. Sedation and hypotension may limit bolus epidural clonidine administration for RSD. The role for chronic epidural infusion of clonidine has not yet been established.

Adult↗

Psychological factors in rheumatoid arthritis.

This article provides a review and discussion of recent developments in psychological research related to rheumatoid arthritis (RA). A description of the medical aspects of the disease is followed by an overview of the literature relating psychological variables to pain and disability in RA; a summary evaluating affective reactions, disease-related beliefs, and coping strategies in RA patients; and a discussion of psychological interventions with this patient population. Methodological weaknesses in the literature are noted and directions for future collaborative research between rheumatologists and psychologists are suggested.

Activities of Daily Living↗

Repression-sensitization differences in recovery from learned helplessness.

The performance of repressors and sensitizers on a solvable anagram task was assessed after either a short delay (0 to 30 min) or a long delay (2 to 6 hr) following a standard learned helplessness induction. Results indicated that all subjects exposed to the learned helplessness induction exhibited performance deficits, compared with control subjects exposed to no induction. Furthermore, subjects who were tested after the short delay did not perform as well as subjects tested after a long delay. No difference in overall anagram performance was found between repressors and sensitizers. Consistent with theoretical predictions, however, the anagram performance of repressor subjects was significantly better in the long-delay than in the short-delay condition; this significant recovery effect between short- and long-delay conditions was not obtained for sensitizer subjects. Possible theoretical mechanisms for these effects and implications for future research are noted.

Adaptation, Psychological↗

Reproductive rate and genetic variation in composite and parental populations: experimental results in sheep.

Mean and genetic variability for ewe performance of two composite populations were compared with those of their contemporary parent lines to assess relative potential for continued response from selection. Data were from the U.S. Meat Animal Research Center, 1973 to 1983. The 4,415 ewes by 508 sires of Finnsheep (F), Rambouillet (R), Dorset (D), and Composite 1 (C1 = F/2 + R/4 + D/4) lines were mated in April, August, and December of each year. The 1,763 ewes by 320 sires of Finnsheep (F), Suffolk (S), Targhee (T), and Composite 2 (C2 = F/2 + S/4 + T/4) were mated in October only. Data were adjusted for effects of year, season, and age of ewe at breeding, plus interval between lambings, for the accelerated lambing lines and for year and age at breeding for the annual lambing lines. Superiority of composite over parent lines in lambs weaned per ewe exposed was 36% for accelerated and 44% for annual lambing lines; that superiority arose largely from dominant heterotic effects for fertility and viability. Weighted mean paternal half-sib estimates of heritability for mean lifetime ewe performance of composite vs parental lines were 32 vs 23% for litter birth weight, 25 vs 28% for lamb birth weight, 26 vs 11% for number born, 11 vs 23% for conception rate, 5 vs 10% for number weaned, -1 vs 19% for lamb weight at 42-d weaning, but 6 vs 23% for number and 8 vs 28% for litter weight weaned per ewe exposed. Heritability was higher in composites than in parental lines for numbers born, but it was lower for the more heterotic traits (fertility, lamb viability) and, hence, for total weaned lamb output, without change in phenotypic variation. Thus, even an equal response in composites from continuing selection for weaned lamb output may depend mainly on more intense selection permitted by a higher reproductive rate.

Age Factors↗

Effects of Duroc, Meishan, Fengjing, and Minzhu boars on productivity of mates and growth of first-cross progeny.

Meishan, Fengjing, Minzhu, and Duroc boars were mated by AI to crossbred gilts to compare the sire breeds for effects on productivity of their mates and performance of their progeny. Gilts were derived from a four-way cross of Chester White, Landrace, Large White, and Yorkshire. At weaning, litters sired by Meishan boars averaged 1.69 and 1.32 more pigs than those sired by Duroc and Minzhu boars, respectively (P less than .05). Pigs sired by Meishan and Fengjing boars averaged 1.2 to 1.8 more nipples than pigs sired by Duroc and Minzhu boars (P less than .05). Minzhu-sired pigs had a lower (P less than .05) survival rate to 14 and 28 d of age than did those sired by Meishan, Fengjing, and Duroc. Fengjing-sired pigs were heavier than Minzhu-sired pigs at birth and heavier than Minzhu- and Duroc-sired pigs at 14, 28, and 56 d of age (P less than .05). At 70 d of age, Meishan-sired pigs were heaviest, followed in order by Fengjing-, Duroc-, and Minzhu-sired pigs. At 98 d of age, Meishan-sired pigs were significantly heavier than all other breed groups and Duroc-sired pigs were significantly heavier than Minzhu-sired pigs. At 126 and 154 d of age, Duroc-sired pigs were heaviest, followed in order by Meishan-, Fengjing-, and Minzhu-sired pigs; all differences were significant. Average backfat thickness of gilts at 99.7 kg was least for Duroc-sired gilts and highest for Meishan-sired gilts. Sire breed groups did not differ significantly in feed efficiency from 70 to 98 d of age. Duroc-sired pigs were the most efficient (P less than .05) from 98 to 126 and 126 to 154 d of age. Results indicate that use of these Chinese breeds in crossbreeding programs will decrease performance traits. This decrease would have to be offset by increases in reproductive efficiency of Chinese sows, use of repartitioning agents, or other management techniques if Chinese pigs are to improve overall production efficiency of a crossbreeding program.

Animals↗

Effects of Duroc, Meishan, Fengjing, and Minzhu boars on carcass traits of first-cross barrows.

Duroc, Meishan, Fengjing, and Minzhu boars were mated to crossbred gilts during two breeding seasons. From each sire breed group each season, six pens of approximately eight barrows each were slaughtered. A pen of pigs from each sire breed group was slaughtered at 7-d intervals from 168 to 203 d of age each season. Breed of sire effects were significant for all age-adjusted carcass traits except carcass length, fat thickness at the last rib, color score, and firmness score. At 184 d of age, Duroc crosses had the heaviest (P less than .05) slaughter and carcass weights; Minzhu crosses were lighter (P less than .05) than Meishan crosses but not lighter than Fengjing crosses. Differences among age-constant traits reflect differences in BW. After adjustment to a constant carcass weight of 78 kg, the three Chinese breeds had very similar carcass characteristics. Carcasses sired by Durocs had significantly less backfat and larger longissimus muscle area than carcasses sired by the Chinese breeds. Weight of each trimmed wholesale lean cut and their total weight were significantly higher for Duroc crosses than for Chinese crosses. Breed of sire means did not differ significantly for belly weight, but Duroc crosses had less (P less than .05) weight of leaf fat. Relative to Chinese crosses, longissimus muscles from Duroc crosses had more marbling (P less than .05). Sire breed groups did not differ significantly for color or firmness score. Pigs sired by Meishan, Fengjing, and Minzhu produced carcasses with significantly less lean content at a carcass weight of 78 kg than did pigs sired by Duroc.

Adipose Tissue↗

A profile of academic medical-psychiatric units.

Medical-psychiatric inpatient programs are a relatively recent phenomenon. Although interest in these programs seems widespread, they are still found primarily at academic medical centers. The authors surveyed 11 such academic units. Variations found between their patient populations, milieu, and organization suggest that these programs, in general, are still in an early stage of evolution. It is hoped that these data will provide a descriptive base of how these programs have developed.

Academic Medical Centers↗

Denial in heart transplant candidates.

The concept of denial is important for the psychosomatic understanding of cardiovascular disease and treatment. This study evaluated denial using several psychometric assessment scales in patients referred for psychiatric evaluations prior to heart transplantation. Surviving patients who had a mean survival of more than 38 months had less denial than nonsurviving patients who had a mean survival of 4 months. These findings are very preliminary, but interesting, and would encourage further investigation of denial in these patients. Denial is a complex psychological variable, only part of which may be applicable to surgery patients.

Denial, Psychological↗

Comparison of Booroola Merino and Finnsheep: effects on productivity of mates and performance of crossbred lambs.

Booroola Merino (BM) and Finnsheep (FS) rams were mated to FS and crossbred (CO) ewes to compare their effects on the productivity of their mates and the performance of their progeny. Effects of breed of ram and the interaction of breed of ram X breed of ewe were no significant for fertility, total number born, number born alive, litter birth weight, or number of lambs weaned by the ewe or in the nursery. Birth weights of FS- and BM-sired lambs were equal, but FS-sired lambs were heavier at weaning and 147 d of age. Compared with BM-sired lambs, survival from birth to weaning of dam-reared lambs was greater for FS-sired lambs produced by CO dams than for FS-sired lambs produced by FS dams. At a constant live weight, FS-sired lambs had a heavier carcass with less external fat thickness than BM-sired lambs. Percentage of ewe lambs reaching puberty was lowest and age at puberty was highest for the BM X CO cross; relatively small differences existed between the other three genotypes for these traits. Ewe lambs sired by BM had a greater ovulation rate than FS-sired ewe lambs. Embryo mortality was greater in BM X CO ewe lambs than in ewe lambs of the other three genotypes; the difference was larger for ewes with three ovulations than for ewes with two ovulations. The net result was that BM X CO ewe lambs averaged slightly fewer lambs born than FS X CO ewes. The BM X FS ewe lambs had larger litters than the FS ewes due to a substantially higher ovulation rate and only a slightly lower overall embryo survival rate. With the exception of ovulation rate and litter size, FS rams produced lambs with a more desirable level of performance than did BM rams.

Animals↗

Effects of breed, heterosis, age of dam, litter size, and birth weight on lamb mortality.

Sources of individual plus maternal effects on lamb mortality were studied in data collected at the U.S. Meat Animal Research Center from 1980 to 1985 for paternal and maternal breeds lambing yearly and for maternal breeds lambing at 8-mo intervals. Records included 16,881 lambs born. Breeds included were Finnsheep (F), Dorset (D), Rambouillet (R), Suffolk (S), Targhee (T), Composite 1 (C1 = F/2, D/4, R/4), Composite 2 (C2 = F/2, S/4, T/4), and Composite 3 (C3 = Columbia/2, S/4, Hampshire/4), Traits analyzed were perinatal, postnatal, and total mortality to 60 d of age and postnatal respiratory, digestive, starvation, injury, and other or unknown causes of mortality. The least squares analyses included breed, year, sire within breed-year, sex, linear and quadratic season and age of dam covariates (Model 1), plus litter size (Model 2), plus birth weight (Model 3), and significant two-way interactions. Age of dam, litter size, and birth weight all had important, often quadratic, effects that differed among breeds. Models 1, 2, and 3, respectively, reduced variation by 8, 10, and 16% for perinatal, 7, 8, and 12% for postnatal, and 9, 11, and 20% for total mortality. In Model 1, breed means ranged from 3.5 to 16.2% for perinatal, 7.2 to 21.1% for postnatal, and 16.7 to 32.8% for total mortality. Respiratory and starvation problems were major causes of postnatal mortality. Heterosis for lamb survival retained in composites was 9% for C1 and 18% for C2. Mortality was 1 to 5% higher for males than for females.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗

Genetic and phenotypic variation in sources of preweaning lamb mortality.

Information on causes of mortality to 8 wk weaning for 16,881 lambs of 10 line-breed groups by 594 sires born over a 5-yr period was analyzed by least squares procedures to estimate sire variance and covariance components within line and year-season. Heritability estimates were approximately 5% for total mortality in the binomial scale and near 10% when converted to a normal scale. Average heritability estimates in the binomial and normal scale were, respectively, 4 and 12% for perinatal and 3 and 7% for postnatal mortality. The heritability estimates for respiratory problems were inconsistent; binomial-scale estimates ranged from 0 to 7% in different populations. Regression adjustment for effects of variation in litter size and birth weight caused only minor changes in the heritability estimates. Comparison of covariances among half-sibs vs full-sibs indicated very large maternal effects on perinatal mortality but smaller and less consistent effects on sources of postnatal mortality. Phenotypic correlations among sources of mortality indicated a 26% greater influence of postnatal than perinatal mortality on variation in total mortality, but both the genetic and phenotypic correlations between those two components were slightly negative. These results suggest that the use of family and progeny test selection for transmitted effects on both perinatal and postnatal lamb viability should be effective.

Animals↗