Regression Of Daughter Research Articles

Calculation of lifetime net income per year (LTNI/year) of Australian Holstein cows to validate the Australian profit ranking of their sires. 2. Validation of the Australian profit ranking of sires and test for genotype by environment interaction based on LTNI/year

In Australia, the Australian Dairy Herd Improvement Scheme publishes the Australian profit ranking (APR), which is an economic index combining all economic traits. The APR is used to select sires that will breed the most profitable daughters. The objectives of this study were to test the predictive power of the APR by looking at the relationship between the APR of sires and lifetime net income per year (LTNI/year) of their future daughters and to test if this prediction was accurate in different types of herds. The importance of re-ranking was also tested by considering LTNI/year of cows in different herds as different traits and estimating the genetic correlation between LTNI/year in different herd types (herds differing in calving systems, region or production level). An additional objective was to test the value of individual trait Australian breeding values (ABV) of sires to predict LTNI/year of their future daughters. The results show that overall the relationship between the APR of bulls and the LTNI/year of their daughters was as expected. That is, the regression of daughter’s LTNI/year on sire’s APR equals 0.5 as expected because cows inherit half their genes from their sire. When LTNI/year of cows was regressed on sire’s APR separately for different herd types, the regression coefficients varied from 0.36 (low production herds) to 0.62 (high production herds). The genetic correlation for LTNI/year between herd types was always high indicating little re-ranking of sires. The lowest was 0.89 between LTNI/year of cows in seasonal and year-round calving systems as well as between Regions 3 (Gippsland and Tasmania) and Region 1 (New South Wales, Queensland, South Australia and Western Australia) herds. Thus, an APR calculated across all herd types will give a good ranking of bulls in any herd type. When LTNI/year of cows was regressed on individual sire ABV the regression coefficients were approximately half the economic weight for each trait as expected. Within seasonal calving and low production herds the regression on sire’s fertility ABV was higher than expected and the regression in year-round and high production herds was less than expected. In conclusion, over all herds the sire’s APR predicts LTNI/year of future daughters as expected. Owners of low production, seasonal calving herds will get slightly less benefit from 1 unit increase in APR than owners of high production, year-round calving herds and could perhaps benefit from placing additional emphasis on the fertility ABV when selecting sires.

Relationship of sire expected progeny differences to milk yield in Brangus cows1,2

Milk yield from 160 Brangus cows sired by 65 Brangus bulls was measured over a 3-yr period with a single-cow milking machine to estimate the relationship of actual milk yield of daughters and their calves' BW with cow sire EPD for milk during the preweaning period. Milk yield was measured six times per year at an average 49, 78, 109, 138, 168, and 198 d postpartum. The regression of daughters' milk yield on sire milk EPD was quadratic (P < 0.01), and the initial linear portion of the curve differed among months (P < 0.05) at an average cow BW. Similarly, the regression of 6-mo average 24-h milk yield on sire milk EPD was curvilinear (P < 0.05). When cow BW was fitted as a covariate in the regression of 6-mo average 24-h milk yield on sire milk EPD, there was an interaction of cow BW with linear sire milk EPD and quadratic sire milk EPD (P < 0.10). The associated response surface suggested that the regression was primarily linear in cows weighing < or = 520 kg and curvilinear in cows weighing >520 kg. A trend existed for the regression of calf 205-d weight on grandsire milk EPD to be curvilinear (P < 0.21); however, the regression of calf 205-d weight on milk yield of their dam was linear (P < 0.01). Results from these data suggest that genetic potential for milk yield, and possibly the associated effects on calf BW transmitted through the grandsire, may have a practical maximum because of nutritional limitations that prevent the expression of genetic potential beyond that level, particularly in heavier cows, which suggests the need to match sire milk EPD and cow BW with production environment.

Lateral cradling preferences in humans (Homo sapiens): similarities within families.

Women (Homo sapiens) tend to cradle infants on the left side of the body. We report the results of a survey of family photograph albums. We found that left-side cradling frequencies (LCFs) are higher in women than in men and that there are strong significant correlations between the LCFs of mothers and daughters, sisters, and maternal grandmothers and granddaughters. There may be a genetic influence on lateral cradling tendencies; women's left-side cradling preferences were found to be repeated with subsequent children. Heritability of women's LCF has an upper limit of 0.82, and the regression of daughters' mean LCF on mothers' LCF gives a heritability of 0.93 +/- 0.29. The data may be interpreted in two ways: There may be sex-limited genes (i.e., genes that express themselves only in women) for lateral cradling preferences, or women may learn cradling preferences from their mothers and other female relatives.

Relationship of beef sire expected progeny difference to maternal performance of crossbred daughters

Cumulative milk production of crossbred daughters of sires of several breeds was estimated using weigh-suckle-weigh procedures. Pooled-across-breed analyses were conducted to determine, in retrospect, relationships of sire EPD values for milk and total maternal value to daughter milk yield and daughter's offspring weaning weight. The pooled coefficient for regression of daughter 214-d milk yield on sire milk EPD was 13.4 kg/kg (residual correlation was .14). The overall mean estimated milk yield was 1,262 kg, suggesting that a difference in sire milk EPD of 1 kg corresponded to a difference of approximately 1% in cumulative daughter milk yield. The pooled coefficient for regression of daughter's offspring 214-d weight on sire total maternal EPD was 1.18 kg/kg (residual correlation was .17). All regression and correlation coefficient stated above were significantly greater than zero. Breeders who use sire milk and total maternal EPD values as selection tools should expect such selection to be effective, on average, but should also expect that a substantial proportion of individuals or small groups may not rank as predicted.

Classical and Bootstrap Estimates of Heritability of Milk Yield in Zimbabwean Holstein Cows

The h2 of first lactation milk yield in Zimbabwean grade Holstein cows was estimated as the regression of daughter on the dams’ adjusted milk yield, using least squares, least absolute value, bootstrap restricted least squares, and bootstrap restricted least absolute value estimators. The estimators were evaluated for efficiency and robustness in estimating h2. The estimated h2 were .272, .265, .283, and .290 by least squares, least absolute value, bootstrap restricted least squares, and bootstrap restricted least absolute value procedures, respectively. The classic 90% confidence intervals for h2 were .030 to .514 by least squares and .056 to .474 by least absolute value procedures. The bootstrap restricted least squares 90% confidence interval for h2 was .000 to .542, and the bootstrap restricted least absolute value 90% confidence interval was .000 to .615. The point estimates by the four procedures were comparable, but the bootstrap confidence intervals were more conservative than their classic counterparts. The least absolute value estimator was the most efficient and the second best in robustness. The least squares estimator was second best in efficiency and worst in robustness. The bootstrap restricted least absolute value estimator was the least efficient and the second best in robustness.

DEVELOPMENT OF DLS BREED OF SHEEP: GENETIC AND PHENOTYPIC PARAMETERS OF DATE OF LAMBING AND LITTER SIZE

Least square means, heritabilities, repeatabilities, genetic and phenotypic correlations of date of lambing and litter size in a population of DLS sheep selected for extended breeding season were estimated by different methods. Mean date of lambing for first, second and third parities was 20 Jan., 6 Jan., 31 Dec. and mean litter size was 1.20, 1.25 and 1.41 lambs, respectively. Heritabilities for date of lambing were 0.37 (sire component, 0.25 (sire and dam component), 0.52 (correlation between full sisters) and 0.17 (regression of daughter on dam). For litter size these methods gave the following estimates: 0.17, 0.14, 0.22 and 0.04, respectively. Repeatability estimates averaged 0.21 for date of lambing and 0.24 for litter size. Genetic correlation between the two traits was calculated at −0.38 (sire component), −0.25 (full sisters) and −0.07 (regression of daughter on dam) while the phenotypic correlation was estimated at −0.19 (P &lt; 0.01). Key words: DLS sheep, heritability, repeatability, genetic correlation, phenotypic correlation, date of lambing, litter size

Sex-limited variability mimicry in the swallowtail butterfly Papilio polyxenes Fabr.

Variation in wing pattern was measured in the swallowtail butterfly Papilio polyxenes, a Batesian mimic of the butterfly Battus philenor. Males and females differed in the number of yellow spots comprising the proximal spot band on the dorsal surfaces of the wings, with females having fewer spots than do males. This difference results in females being more similar to B. philenor than are males. However, females were also more variable in spot number than were males. Full sib analysis of variance of females and regression of daughters on mothers indicates that variation in spot number is heritable. The ventral surfaces of the wings of males and females showed little variability and were similar to those of B. philenor, suggesting that the adaptive significance of the dorsal surface wing pattern differs in males and females. Possible reasons for such a difference are discussed and a model based on the genetics of mimicry in P. polyxenes and developmental studies of wing pattern formation in butterflies is proposed to account for the suppression of variability in male wing pattern.

Influences of Dam on Calving Difficulty and Early Calf Mortality

Influence of dam on calving difficulty and calf mortality was evaluated for repeatability of past performance and daughter-dam relationships. Repeatability for calving performance at first with second parity was .16 and for consecutive calvings at second and later parities .10. Repeatability for calf mortality from first to second parity was .02 and for consecutive calving at second and later parities .02. A small but real tendency existed to repeat prior calving performance but not calf livability. Repeatabilities for dystocia were approximately double heritability. Difficulty scores should not be combined because of loss of predictive value of future performance. Relationship of calving difficulty to calf mortality varied depending on whether the calf was born dead or died within 48h postpartum. Livability scores for those classes should not be combined when calf mortality-calving difficulty interactions are investigated.The hypothesis of negative direct maternal correlation for dystocia resulting from small calves born with ease becoming small cows that have increased dystocia was not disproven for first and second parities. Cows with above average difficulty produced daughters with above average difficulty, and heritability of dystocia as a trait of the dam was .24 by regression of daughter on dam.

Regression of Abdominal Fat in Broilers on Abdominal Fat in Spent Parents

A total of 261 pedigreed broilers out of 10 sires and 27 dams from a high fat line and 378 pedigreed broilers out of 11 sires and 34 dams from a low fat line were probed in the vent at 8 weeks of age as an indirect measure of abdominal fat. The broilers were weighed alive, slaughtered, and eviscerated. Abdominal fat, eviscerated carcass without giblets, and carcass shell weights were taken for each chicken. The correlations between caliper measurements and abdominal fat were below +.2. The sires and dams of the two lines were weighed alive at 14 months of age, slaughtered, eviscerated, and the same carcass measurements taken as for their broiler progeny. Sixteen of 21 sires had no measurable abdominal fat. The dams averaged 3.44% abdominal fat of live body weight compared with 1.55% for their female broiler progeny. The coefficient of variation for abdominal fat as a percentage of live weight of dams was 28%. Regressions of daughters and sons on midpoint of parents for abdominal fat as a percentage of live weight was +.305 and +.204, respectively, and were significant (P≤.05). The regression of daughters on dams and of sons on dams for abdominal fat as a percentage of live weight was +.186 and +.154, respectively, and both were significant (P≤.01).

Heritability of Teat Shape and Teat End Shape in Cattle

Lojda L., M. Stavikova, J. Polai!ek.: Heritability of Teat Shape and Teat End Shape in Cattle. Acta vet. Bmo, 51, 1982: 59-67. Heritability of teat shape and teat end shape was studied in Bohemian Pied cows. Teat shape was evaluated by visual inspection and on the basis of indices 11 and II pro­ posed in this study. The coefficients of heritability of the two indices computed from the regression of daughter on dam in 185 dam-daughter pairs were 0.380 ± 0.08 and 0.354 ± 0.08, respectively. The coefficient of heritability of teat end shape com­ puted from the dam-daughter regression was 0.414 ± 0.17, but the coefficient of her i­ tability of this characteristic computed by means of the intraclass correlation coefficient in groups of paternal half sisters sired by 30 bulls was only 0.085. Fourteen pairs. of dizygotic twins were included in the study to investigate their concordance with regard to teat shape and teat end shape. Half of the pairs of twins both had all 4 teats of equal shape; 3, 2 and 1 equally shaped teats were found in 3, 1 and 1 pairs, res­ pectively, and two pairs were completely discordant. The concordance of twins with regard to teat end shape was also considerable: 78.5 per cent of the pairs both had 4, 3 or at least 2 teats with equally shaped ends and only 2 pairs were completely discor­ dant. Where the dams of the twins were available for comparison, their teat and teat end shapes agreed with those of one of their daughters at least. Cattle, heritability, teat shape, teat end shape, mastitis.

Changes in Egg Production and Egg Intervals Under Selection for High Egg Number under 22 our Day Cycles of Artificial Lighting

Data were collected from eight generations of selection for 40 weeks egg production in line UCD-126 of White Leghorns. Hens were kept under a 22 hr day cycle with normal light-dark ratios. Each generation's exact time of lay was recorded for a period of about 30 days for a sample of hens when hens were about 30 weeks old. The percent of time intervals between eggs shorter than 24 hr (“back steps”) were determined for each hen from time-of-lay records.Forty week egg production increased through the selection period of an average of 2.6 eggs per year. There was a correlated response in the percent of ‘back steps,” with an average increase of 1.8% per year.For 40 weeks egg production, the regression of generation means on dams’ cumulative selection differential was .193 and the regression of daughters on their dams was .216. For percent of “back steps,” the daughter-dam regression was very low (.043), but this trait was found to be correlated with 40 week egg production, with the estimates rp = .293 and rg= .308.Some advantages of selecting hens for egg production under short day-cycles of 22 hours instead of using short time-intervals between eggs are discussed.

Genetic parameters of several measures of milk flow rate and milking time.

Heritabilities and genetic correlations of milking rate, time, and yield were estimated by intrasire regression of daughter on dam for 252 Holstein pairs. Heritabilities were: lactation yield, .51 +/- .11; peak rate, .47 +/- .11; bucket milk yield, .38 +/- .10; average rate, .37 +/- .12; milk yield to .45 kg/min, .19 +/- .12; total time, .17 +/- .12; duration of peak rate, .10 +/- .10; strip time, .08 +/- .15; yield during peak rate, .07 +/- .11; and strip yield, .01 +/- .17. The genetic correlation of peak rate with lactation milk yield was .69 +/- .08, indicating substantial genetic improvement in milking rate by selecting for milk production. The genetic correlation between total milking time and lactation milk yield was .50 +/- .20, indicating an increase in total milking time due to selection for milk. Direct selection for peak rate would provide an opportunity to reduce total milking time.

Regression of Daughter and Herdmate Milk Yield on Genetic Value of the Herdmates’ Sires

The effect that average genetic value of the herdmates’ sires has on daughter deviation from herdmate average and consequently upon sire summaries was examined. Lactation records from a national sample of herds from five breeds on official Dairy Herd Improvement testing were used. Regressions within sire, within year of calving of a) daughter yield, b) various herdmate averages, and c) daughter deviations from herdmate averages on average Predicted Differences of the herdmates’ sires were calculated.As average Predicted Difference for herdmates’ sires in artificial insemination (AI) increased, so did first lactation daughters’ yield (b = .35 to .73) and AI herdmate average (b = 1.34 to 1.78), but the daughters’ deviation from AI herdmate average decreased (b = −.72 to −1.14). Standard errors showed that these latter regressions were not different from minus one. Regression using artificial insemination contemporaries in both first and second lactation gave results similar to those expected. These results indicate that differences between bulls in the genetic value of herdmates affect present sire summary procedures and cause some misrankings among bulls. These regressions provide evidence that adjusting for the average genetic value of the herdmates’ sires would significantly increase the accuracy of herdmate comparison sire summaries.

MATERNAL EFFECTS ON LITTER SIZE IN MICE

An extensive set of data from a selection experiment for 12-day litter weight in mice was analyzed to determine whether standardizing litter size to a constant number at 5 days of age removed the negative environmental maternal effect (acting through adult body weight of the daughter) on litter size. The regression of daughters' litter size on dams' litter size was 0.070 ± 0.013 (d.f. = 851), which was partitioned into a relatively large direct additive genetic effect (0.067) and a negligible environmental maternal effect (0.003). Evidence is also presented that a positive genetic maternal effect influences litter size, which is probably mediated through adult body weight.

The genetic basis of growth, reproduction, and maternal environment in Romney ewes

This paper is the first in a series of studies on the genetic variation and covariation in growth and reproductive characters of the New Zealand Romney sheep. The data used were obtained over a period of 11 years (1955-1965 inclusive) from a random-bred experimental flock maintained at Massey University, Palmerston North, New Zealand. Among the environmental factors studied, type of birth and rearing has a marked effect on liveweights measured at different times from weaning to the yearling stage. On average, the singles were about 9 lb heavier than the twins at weaning, or c. 17 % heavier in terms of the mean weaning weight. Presumably because of their pre-weaning growth handicap, the twins compared with the singles exhibited post-weaning compensatory growth. The age of the dam and of the individual moderately affected the weaning weight of the lamb. However, their effects on post-weaning liveweight characters over the hogget stage (from weaning to about 14 months) showed that the influence of age of dam remained undiminished whereas that of the individual tended to decrease with time from weaning. The number of times a ewe hogget comes into oestrus during the first autumn of her life (number of hogget oestruses) was unaffected by type of birth and rearing, moderately affected by age of the individual, but relatively strongly influenced by the age of dam effect. Some doubt existed as to whether the average difference in fertility (number of lambs born per ewe) between ewes themselves born as singles and twins (type of birth effect) could be regarded as environmental or as genetic in nature. The present results indicated that in the fertility data, type of birth effect contained a genetic component, and adjustment should not be made for difference in type of birth if the aim is to study genetic variation and covariation in fertility of the ewe. The estimates of heritability for the various characters were made. by using paternal half-sib correlation (method 1) and regression of daughter on dam (method 2). In general, good agreement existed between corresponding values of heritability obtained by different methods of analysis. The estimates of heritabilities by methods 1 and 2 were: weaning weight (December) 0.30 and 0.23; March liveweight, 0.45 and 0 35; June liveweight, 0.39 and 0.42; hogget liveweight (yearling in October), 0.51 and 0.46; number of hogget oestruses, 0.32 and 0.27; number of lambs born per ewe at the first lambing (2-year-old), 0.053 and 0.045; over the first two lambings, 0.121 and 0.111; over the first three lambings, 0.032 and 0.205. The results are discussed in relation to genetic improvement in the ewe's fertility by direct selection.

Heritabilities of Certain Immature and Mature Body Measurements and Their Correlations with First-Lactation Production of Holstein Cows

Heritabilities of body weight estimated from heart girth, height at withers, chest depth, and body length taken at three ages before calving, after first calving, and after five years of age, along with phenotypic and genetic correlations between these traits and first-lactation mature equivalent milk or milk fat yields of Holstein cows were computed. Heritabilities and genetic correlations for precalving-age measurements were obtained from paternal-sister and also from daughter-dam resemblances. The remaining estimates were based on paternal-sister data. The analyses included 529 to 2,367 observations.Estimates of heritability from all available paternal-sister data for body measurements at three, six, and 12 months of age varied from .10 to .52. Similar estimates from regression of daughters on dams ranged from −.06 to +.61. Phenotypic correlations between body measurements taken at precalving ages and milk or milk fat yields varied from −.03 to +.15. Genetic correlations between body weight or chest depth at three, six, or 12 months of age and production from all available paternal-sister data ranged from .34±.27 to .90±.34. Similar genetic correlations for the two remaining traits were usually positive but lower. In contrast with this, genetic correlations from daughter-dam analyses varied from −.45 to +.31.A 25% increase in accuracy of selection for first-lactation milk production was indicated for inclusion of precalving age body measurements in a selection index. Similar selection restricted to body measurements would have been 80% as effective as selection based on a milk record.

Composition of Cows’ Milk. II. Genetic Influences

Heritabilities and genetic correlations were estimated from 4,552 records on 3,472 Holstein-Friesian cows by 630 sires. Heritabilities by paternal half-sib correlation of deviations from herdmates were milk yield, .23; fat yield, .09, solids-not-fat yield, .22; fat per cent, .45; and solids-not-fat per cent, .47. Heritabilities by regression of daughter on dam with 438 pairs of records were milk yield, .37; fat yield, .22; solids-not-fat yield, .27; fat per cent, .55; and solids-not-fat per cent, .25. Genetic correlations among yields were milk fat, .79; milk solids-not-fat, .95; fat solids-not-fat, .85. Selection for milk yield should give 94% as much gain in solids-not-fat yield as would direct selection for solids-not-fat yield.

Heritability Estimates when Dams and Daughters are in the Same and Different Herds

The regression of daughter on dam deviations of Holstein first-lactation milk production from herd-mate averages was computed for 38,440 pairs of records made in the same herd and for 10,256 pairs of records where the daughter was in one herd and the dam in another. The corresponding heritability estimates were .42 and .40, respectively, which suggest an environmental covariance of .01 between records of daughters and dams in the same herd. Other analyses were conducted for dams with two daughters with records where 1) both had records in the same herd as the dam, 2) only one had a record in the same herd as the dam, 3) the daughters were full sibs, in the same herd as the dam, 4) the daughters were full sibs, only one in the herd of the dam. These analyses also indicated no evidence for much environmental covariance between daughter and dam records in the same herd. The environmental covariance between records of maternal half-sisters in the same herd is apparently small, but the environmental covariance between records of full sibs in the same herd may be important—.06 to .12 of total variance. Genetic maternal variance was not excluded as a source of likeness between the records of maternal relatives.

Linearity of Heritability of Holstein First-Lactation Milk Production

The regression of daughter on dam first-lactation milk deviations from herd-mate averages was found to be linear from an analysis of 47,400 Holstein pairs. The linear equation was y=−25.6+.210 (x −27.6) and the quadratic equation was y=−25.6+.208 (x −27.6) + .0000222 (x2−44131.4) with correlation coefficients, .18258 and .18268, respectively. These results suggest that selection response can be predicted adequately even with very large selection differentials.

Genetic and Environmental Factors in Dairy Sire Evaluation. I. Effects of Herds, Months, and Year-Seasons on Variance Among Lactation Records; Repeatability and Heritability

More than 39,000 Iowa Dairy Herd Improvement Association (DHIA) and Dairy Herd Improvement Registry (DHIR) Holstein lactation records provided the basic data for checking some of the parameters and assumptions currently used in dairy sire evaluation procedures in the United States. The components of variance for herds were about 32% of the total variance with both milk and milk fat records but only 17% with test. The components for months were 1.4 and 1.7% of the total variance with milk and milk fat records and only slightly higher for year-seasons. However, the interactions of herds with months and year-seasons contributed 3 to 5% of the total variance.Grouping of records according to either rolling year-seasons or fixed year-seasons was about equally suitable as a means of removing year-season variance with deviation records. However, the pooling of records from more than one year into season averages was less effective, because significant year-season variance remained in the deviations.Repeatabilities of records expressed as deviations from herd-year-season averages were .50, .47, and .72 for milk, milk fat, and test, respectively. Heritabilities, estimated as twice the regression of daughter on dam, within herd-year-seasons, were .22, .18, and .53 for milk, milk fat, and test.