Maternal Grandsire Research Articles

Genetic Relationship Between the United States and Canadian Holstein Bull Populations

The average additive genetic relationship and degree of connectedness between American and Canadian Holstein AI bull populations were estimated. This project was undertaken to determine the feasibility of a joint United States-Canadian sire evaluation to estimate genetic base differences between the two countries‘Holstein bull populations. Data were provided by USDA and Agriculture Canada for bulls evaluated in each country. Bulls were designated as American, Canadian, or dual national origin based on their country of registration and national origin of their parents. A total of 13,079 American, 1683 Canadian, and 256 dual origin bulls were included in the inverse relationship matrix. When both sire and maternal grandsire relationships were included in the matrix, there were 174 disconnected groups; however, 99% of the American bulls and 97% of the Canadian bulls were in a single group. The average aij between the American and Canadian population was 4.6×10−5. Despite the low average additive relationship between the two national populations, the high degree of connectedness in the inverse relationship matrix, when using both sire and maternal grandsire relationships, suggests sufficient genetic ties between the two populations to conduct a meaningful joint sire evaluation.

Joint Sire and Cow Evaluation for Conformation Traits Using an Individual Animal Model

A joint sire and cow evaluation for selected type traits has been carried out for the Canadian Holstein population using an individual animal model accounting for all known relationships. Only first lactation, first classification linear records were utilized. Linear scores for final class/final score (combined), feet and legs, mammary system, and stature were analyzed. The model of analysis included animals’ additive genetic merit as random and herd-round-classifier subclasses as fixed effects. Calving age and stage of lactation at classification were fitted as linear and quadratic covariables. There were 282,030 cows with records, 198,871 dams without records, and 8481 sires (i.e., 489,382 animals in total). Combined with 33,968 herd-round-classifier effects in 9654 herds and four regression coefficients, a system of 523,354 equations required simultaneous solution. Solutions were obtained iteratively for one trait at a time. The computing strategy utilized is described, and a detailed worked example is given. Correlations between sire proofs and the current Holstein sire proofs were .89 to .96 for sires with at least 20 daughters in five or more herds. Correlations between cow indexes and phenotypic scores ranged from .53 to .76. The coefficient of determination in a multiple regression of daughter's index on dam's index and sire's and maternal grandsire's proof was 78 to 92% but only 59 to 83% when dam's index was replaced by dam's phenotypic record.

EFFICIENCY OF FEED UTILIZATION BY THREE-BREED CROSS STEERS

Feed efficiencies, defined as feed-to-gain or weight ratios, were computed on 1046 steers reared between 1973 and 1978 at the Brandon Research Station. The progeny were out of 10 specific F1 crosses of dams mated to Charolais (C), Simmental (S), Limousin (L), and Chianina (Chi) bulls with none of the F1 dams being backcrossed. Dam crosses included the Hereford × Angus (HA) and crosses sired by C, S, and L bulls out of Hereford (H), Angus (A), and Shorthorn (N) dams. Feed-to-gain ratios were calculated on a live animal postweaning basis (for both a 140-d test and total liveweight gain from on-test to slaughter) and a carcass basis (hot carcass weight and rough or untrimmed lean, fat, and bone weights of combined cuts). The combined cuts were the rib, long loin (comprising the short loin and the sirloin butt), and round. In the live animal traits, the progeny from the 10 F1 dam crosses did not differ, but on a carcass basis, the progeny from the "exotic" crosses had better feed-to-gain ratios than the HA cross. Differences among the progeny of the "exotic" crosses included: C crosses < L crosses, "exotic" × A and "exotic" × N < "exotic" × H for hot carcass weight; "exotic" × N < "exotic" × H for rough weight of the combined cuts; S crosses < L crosses and "exotic" × N < "exotic" × A for fat and bone weights of the combined cuts; and "exotic" × N < "exotic" × H for fat weight of the combined cuts. There were no significant breed of dam's sire (maternal grandsire) × breed of dam's dam (maternal grand-dam) effects. Differences in breed of dam's sire were C < S for 140-d test, C < L for total liveweight gain, and S < L for bone weight of the combined cuts. Breed of dam's dam differences were N < (A = H) for fat weight of the combined cuts. Breed of terminal sire effects revealed that the progeny from the S and C breeds were similar for all measures of feed efficiency and the L and C breeds were only similar for feed efficiencies expressed on a carcass basis. Progeny from the Chi breed were comparable to the progeny from the C breed but not to the progeny from the S and L breeds in these traits. Key words: Beef cattle, breed crosses, steers, feed efficiency

Interaction of Maternal Grandsire with Region of United States and Herd for Calving Ease, Birth Weight and 205-Day Weight

Field records supplied by the American Simmental Association from 2-yr-old dams were used to study maternal grandsire × region of the U.S. and maternal grandsire × herd within region (herd/region) interactions. Regions were 1) Montana, North Dakota and South Dakota, 2) Kansas and Nebraska, 3) Texas and Oklahoma and 4) Alabama, Florida, Georgia, Louisiana and Mississippi. Analyses were conducted pair wise with respect to region with the following number of animals in each comparison: 1 (3,964) vs 2 (2,239), 1 (3,996) vs 3 (1,660), 1 (3,418) vs 4 (474), 2 (2,033) vs 3 (1,709), 2 (1,666) vs 4 (443) and 3 (1,372) vs 4 (430). Independent variables were the fixed effects of region, sex of calf, Simmental percentage of the calf (75 to 88%) and the random effects of herd/region, maternal grandsire, maternal grandsire × region and maternal grandsire × herd/region. Records were adjusted to account for the direct effect of maternal grandsire in the maternal grandsire component. Dependent variables were calving ease score, birth weight and 205-d weight. Region was significant in all analyses except for 1 vs 2, 1 vs 3 and 2 vs 3 for calving ease score and 2 vs 3 for birth weight and 205-d weight. Herd/region was significant in all analyses. Maternal grandsire was significant in all analyses for calving ease score and birth weight and for 1 vs 2 for 205-d weight. Maternal grandsire × region was not significant in any analysis. Maternal grandsire × herd/region was significant in four of six analyses for birth weight and 205-d weight, but was not significant in any analysis for calving ease score. Maternal grandsire, maternal grandsire × region interaction and maternal grandsire × herd/region interaction accounted for an average of 4, 0 and 1%; 3, 0 and 5%; and 0, 0 and 3% of the total variation for calving ease, birth weight and 205-d weight, respectively. Genetic correlations of maternal grandsires' progeny performance in different herds ranged from .20 to .74 for birth weight and from .05 to .34 for 205-d weight, indicating significant changes in rank from herd to herd.

Maternal heterosis and grandmaternal effects in beef cattle: postweaning growth and carcass traits.

Crossbred steer and heifer progeny from 5-, 6- and 7-yr-old dams produced in a four-breed diallel crossing experiment involving the Brown Swiss, Red Poll, Hereford and Angus maternal grandsires and maternal granddams were evaluated for postweaning growth and carcass traits to estimate breed mean maternal heterosis, maternal heterosis for specific breed cross females, average maternal heterosis for all crosses, breed grandmaternal effects and net breed effects in crosses. All progeny evaluated were born in 1979 and 1980 and were sired by 7/8 or 15/16 Simmental bulls. Average maternal heterosis was significant for 200-d weight in heifers but not in steers and was not significant for final weight (444-d) in either heifers or steers. The effects of maternal heterosis on postweaning growth were not important. Differences among breeds in mean maternal heterosis values were small for growth-related traits. Breeds did not differ (P greater than .05) in grandmaternal effects for growth-related traits; Brown Swiss tended to be highest, Red Poll lowest, with Hereford and Angus intermediate. Differences in net breed effects in crosses favored Brown Swiss over the three other breeds and were generally significant for growth traits. Average maternal heterosis, though generally positive, was not significant for carcass traits on either an age-constant or weight-constant basis. Differences among breeds were small in grandmaternal effects, specific heterosis and net effects in crosses for carcass traits associated with both weight or composition; generally the Brown Swiss breed was favored on carcass traits associated with weight in the age-constant analysis and generally had a higher lean-to-fat ratio than the three other breeds in both the age-constant and weight-constant analyses.

Estimation of variance and covariance components to determine heritabilities and repeatability of weaning weight in American Simmental cattle.

Components of (co)variance for weaning weight were estimated from field data provided by the American Simmental Association. These components were obtained for the observational components of variance corresponding to a sire, maternal grandsire, and dam within maternal grandsire model. From these estimates, direct additive genetic variance (Sigma2A), maternal additive genetic variance (Sigma2M), covariance between direct and maternal additive genetic effects (SigmaAM), variance of permanent environment(Sigma2pe) and temporary environment variance(Sigma2te) were determined. A procedure to approximate restricted maximum likelihood (REML) estimates of the observational components of variance based on the expectation-maximization (EM) algorithm is described. From these results, phenotypic variance ( ) of weaning weight was 667.88 kg2. Values forSigma2A, Sigma2M, Sigma2pe and Sigma2te were 79,30,58,38,49.45, and 469.97 kg2, respectively. Genetic correlation between direct and maternal additive genetic effects was .16.

Analysis of gestation length in American Simmental cattle.

Records of gestation length (71,461) for Simmental cattle were distributed with mean 284.3 d and standard deviation 5.52 d. Gestation length was found to increase with percent Simmental and was 1.9 d longer for calves born to mature dams than for those born to heifer dams. Bull calves experienced gestation lengths 1.5 d longer than heifer calves. Sire, maternal grandsire, residual and total variances were estimated to be 2.42, .58, 22.78 and 25.78 d2, respectively, by Henderson's Method III. Heritability of gestation length was calculated to be .374 from the sire variance and .09 from the maternal grandsire variance. Direct additive genetic variance was considered to be of greater importance than maternal additive genetic variance. Correlations between the evaluations of sires for gestation length and heifer calving ease, birth weight and weaning weight were .26, .26 and .13, respectively.

Cytoplasmic Genetic Effects on Preweaning Growth and Milk Yield in Hereford Cattle

Performance records on Hereford cattle raised in two herds were used to evaluate cytoplasmic genetic effects on preweaning growth and milk production. Animals were traced through maternal lineage to foundation females to form cytoplasmic lines. Growth records were available on 1,189 calves at Raleigh and 1,599 at Plymouth representing 27 and 15 cytoplasmic lines, respectively. Milk records were available on 418 cows at Raleigh and 522 cows at Plymouth, representing 20 and 13 cytoplasmic lines. After adjustment for sire, cytoplasmic effects were significant for birth weight (BWT), average daily gain (ADG) and 205-d weight (WT205) in both herds. Cytoplasm accounted for 2, 5 and 5% of the variance for BWT, ADG and WT205 at Raleigh; and 1, 2 and 2% of the variance at Plymouth. After addition of maternal grandsire to the model, cytoplasm was still significant; however, variances were reduced at Plymouth. Cytoplasmic effects for milk yield were important at Raleigh (P less than .01) but marginal at Plymouth (P = .10). Variance components for cytoplasm accounted for 4 and 1% of the variance for milk yield at Raleigh and Plymouth, respectively. Ranges for least-squares constants for cytoplasmic lines corresponded to one of two standard deviations. Correlations among least-squares constants for ADG, WT205 and milk yield were high, suggesting that cytoplasmic effects were mediated through milk production. More research is needed to confirm these results before cytoplasmic inheritance is considered in breeding programs for beef cattle.

Maternal heterosis and grandmaternal effects in beef cattle: preweaning traits.

Crossbred progeny from females, 3 yr old and older, representing Brown Swiss (B), Red Poll (R), Hereford (H) and Angus (A) maternal grandsires and maternal granddams in a diallel crossing experiment were evaluated to estimate breed mean maternal heterosis (mean hMi) for each breed, maternal heterosis for specific breed cross females (hMij), average maternal heterosis for all crosses (mean hM) and breed grandmaternal effects (gM'i) for preweaning calf traits. Estimates of mean hM were significant for birth date and weight, 200-d weight and 200-d weight/cow exposed. Even though calves with crossbred dams weighed more at birth, they did not differ from calves with straightbred dams in frequency of calving assistance. The estimates of hMij were similar for most crosses and most traits, except 200-d weight and 200-d weight/cow exposed. The largest heterotic advantage was exhibited by progeny of BH reciprocal cross females, which exceeded crossbred progeny from BB and HH females for 200-d weight/cow exposed by 35.9 kg. The smallest heterotic effect was exhibited by crossbred progeny of RA reciprocal cross females. Progeny with R maternal granddams exhibited a higher (P less than .05) live calf born and weaned percentage than progeny with H maternal granddams. Progeny with B maternal granddams were born later (P less than .05) in the calving season than progeny with R maternal granddams. Progeny with A maternal granddams exhibited a lower frequency of calving assistance than progeny with H maternal granddams, and progeny with H maternal granddams were heavier (P less than .05) at 200 d than progeny with R maternal granddams. There was a tendency for estimates of breed grandmaternal effects (gMi) to exhibit an inverse relationship with estimates of breed maternal effects (gMi).

Inheritance of active and acquired immunity traits in sheep.

Six hundred sixteen ewes of six strains were inoculated twice with ovalbumin in Freunds' incomplete adjuvant. To quantify the humoral immune response to the foreign antigen, blood samples were collected from all ewes 1 wk post-second injection. Blood samples were also collected between 4 and 40 h of age from their 709 lambs, to examine genetic differences in ability of lambs to acquire maternal anti-ovalbumin antibodies. Titers of anti-ovalbumin antibodies were determined using kinetic enzyme-linked immunosorbent assay (ELISA) techniques. Strain did not affect ewe immune response, but sire within strain was highly significant. In pregnant ewes, anti-ovalbumin antibody titers in 12- and 30-mo-old ewes were higher than those in 21-mo-old ewes. Number of lambs in utero did not significantly affect ewe immune response. Heritabilities of anti-ovalbumin titer from a paternal half-sib analysis were .27 +/- .17 for all ewes and .57 +/- .25 for only the pregnant ewes. The effect of strain of lamb on lamb anti-ovalbumin titer approached significance, and sire within strain was highly significant. Lamb anti-ovalbumin antibody concentration increased as time from birth to blood sampling increased to 18 h but declined thereafter. The size of the litter in which a lamb was born had a highly significant effect on the lamb's acquired immunity, with titer decreasing as litter size increased. The heritability estimate for lamb anti-ovalbumin antibody concentration from a paternal half-sib analysis was .38 +/- .11; it was .28 +/- .15 from the sire variance component of a full-sib analysis. When lamb titer was considered a maternal trait (lambs nested within their maternal grandsires within strains), the maternal grandsire variance component was negative. The average anti-ovalbumin antibody concentration of lambs that died between blood sample collection and 120 d of age was less than the average antibody concentration of lambs that survived (P less than .01).

Genetic parameters of growth of Ethiopian Boran cattle

ABSTRACTRecords on birth weight and pre-weaning growth of 3959 Boran calves, which were progeny of 51 sires and 979 dams, were analysed by least-squares analysis of variance. The variance components for sires, dams and maternal grandsires were estimated from the data. On the basis of assumed genetic correlations −0·44 and −0·55 between direct and maternal effects on birth weight and weaning weight, respectively, the maternal genetic component and the genetic covariance between direct and maternal effects were estimated. The heritabilities for direct effects on birth weight and weaning weight were 0·11 and 0·22, respectively, while the heritabilities of maternal effects were estimated as 0·02 and 0·11, respectively for the same traits. Selection indices for direct and maternal genetic components of weaning weight were constructed for practical use. These selection indices combined information on the individual, the parents and sibs.

THE EFFECT OF DIFFERENT NUMERATOR RELATIONSHIP MATRICES ON BREEDING VALUES ESTIMATED FROM MULTIPLE TRAIT BLUP

A numerator relationship matrix (Ac) due to sires and dams was compared with a numerator relationship matrix (Ai) due to sires and maternal grandsires in a multiple-trait-reduced animal model (MT-RAM). Best linear unbiased predictors of estimated breeding values (EBV) for 200-d weight (WW) and postweaning gain (PG) (gain from 200 to 365 d of age) were estimated from data simulating a beef cattle population. As expected, mean EBV and bias (EBV-BV) for both traits were not significantly affected by different relationship matrices. The mean variances of EBV with Ac were larger than those with Ai for both traits. The mean EBV variances were closer to mean BV variances with Ac compared to Ai, which is consistent with increased precision of EBV. Product-moment correlations of EBV and BV (accuracy of prediction) were not equal (P < 0.01) for Ac compared to Ai with WW or PG. The EBV using Ac were more accurate than EBV using Ai. The increased precision and accuracy of EBV from a MT-RAM with Ac would result in greater genetic progress in the population. Key words: Relationship matrices, estimated breeding values, MT-RAM

Symmetric differences squared and analysis of variance procedures for estimating genetic and environmental variances and covariances for beef cattle weaning weight: II. Estimates from a data set.

Analysis of variance (ANOVA) and symmetric differences squared (SDS) methods were used to estimate additive genetic and environmental variances and covariances associated with weaning weight. The two methods were applied to 503 beef records collected over 19 yr from a relatively unselected university Angus herd. The SDS methodology was used with four models. The first model included direct (g) and maternal (gm) additive genetic effects, the genetic covariance between direct and maternal additive genetic effects (sigma ggm), permanent maternal environmental effects (m) and temporary environmental effects (e). The second model also allowed for a nonzero environmental covariance (sigma mem) between dam and offspring weaning weights. Models 3 and 4 were models 1 and 2, respectively, expanded to include a grandmaternal genetic effect (gn) and covariances sigma ggn and sigma gmgn. Two ANOVA solution sets for the parameters of model 4 were based on sire, dam, maternal grandsire, maternal grandam and phenotypic variances and offspring-dam (covOD), offspring-sire (covOS), offspring-grandam (covOGD) and offspring-maternal half-aunt or uncle (covOMH) covariances. Four ANOVA solution sets for the parameters of model 2 were based on sire, dam, within dam and maternal grandsire variances, covOD and either covOS or covOGD. Symmetric differences squared estimates of h2g and h2gm averaged .30 and .16, respectively. All SDS estimates of rho ggm (correlation between direct and maternal genetic effects) were less than -1. Estimates of sigma mem were positive. Both SDS estimates and one of the two ANOVA estimates of the grandmaternal variance were negative. The ANOVA model 4 estimates of h2g were .33. The estimates of h2gm were .44 and .39, while the estimates for rho ggm were -.88 and -.80. Both estimates of sigma mem were positive. The four ANOVA model 2 estimates of h2g and h2gm averaged .33 and .48, respectively. Three of the four estimates of rho ggm were less than -.97; the fourth was .35. Three of the four estimates of sigma mem were positive. Expectations show the extent to which SDS and ANOVA estimators were biased by nonzero grandmaternal components that were not accounted for. The extent to which dominance components bias the ANOVA estimators also is shown. Nonzero grandmaternal effects need to be taken into account in either SDS or ANOVA solution sets, or important biases occur with most of the estimators. More numerous, and generally more severe, biases occur with ANOVA estimators than with SDS estimators in solution sets that do not account for grandmaternal effects.

PEDIGREE INDEXING YOUNG HOLSTEIN DAIRY BULLS USING ANCESTRAL INFORMATION FROM DIFFERENT COUNTRIES

A model is described for utilizing ancestor estimated transmitting abilities from different countries to increase the accuracy of prediction of the performance of young dairy bulls in artificial insemination within a country. The model was applied to young Canadian Holstein bulls having pedigree information from Canada and the United States. Models with varying sources of pedigree information were compared. When sire, dam and maternal grandsire were in the model, the correlations between pedigree index and actual progeny test were 0.64, 0.70 and 0.55 for milk yield, fat yield and fat percentage, respectively. There was little difference in accuracy using a sire and dam model. Average pedigree indices were calculated for bulls in artificial insemination in Canada. The average pedigree index has increased 0.87 BCA (breed class average) per year for milk yield over the last ten years. Key words: Holstein sires, pedigree indexes, production traits

Symmetric Differences Squared and Analysis of Variance Procedures for Estimating Genetic and Environmental Variances and Covariances for Beef Cattle Weaning Weight: I. Comparison via Simulation

Analysis of variance (ANOVA) and symmetric differences squared (SDS) methods for estimating genetic and environmental variances and covariances associated with beef cattle weaning weight were compared via simulation. Simulation was based on the pedigree and record structure of 503 beef weaning weights collected over 19 yr from a university herd. The SDS methodology was used with four models. The simplest model included direct (g) and maternal (gm) additive genetic effects, genetic covariance between direct and maternal additive genetic effects (sigma ggm), permanent maternal environmental effects (m) and temporary environmental effects (e). The second model also allowed for a nonzero environmental covariance (sigma mem) between dam and offspring weaning weights. Models 3 and 4 were models 1 and 2, respectively, expanded to include a grandmaternal genetic effect (gn) and covariances sigma ggn and sigma gmgn. Two ANOVA solution sets for the parameters of model 4 were obtained using sire, dam, maternal grandsire, maternal grandam and phenotypic variances and offspring-dam (covOD), offspring-sire (covOS), offspring-grandam (covOGD), and offspring-maternal half-aunt or uncle (covOMH) covariances. Four ANOVA solution sets for the parameters of model 2 were obtained using sire, dam, within dam and maternal grandsire variances, covOD and either covOS or covOGD. Two sets of 1,000 replicates of the data were simulated. These data were used to compare precision and accuracy of SDS and ANOVA estimators, to estimate correlations among SDS and ANOVA estimators, and to study the importance of taking inbreeding into account with SDS methodology. All ANOVA estimators for rho ggm were biased downward. The SDS procedure had a clear advantage over ANOVA. Averages of SDS estimates were closer to parameter values used to simulate the data and their standard deviations were generally smaller. The standard deviations of both SDS and ANOVA estimates of rho ggm were very large. It is important to allow for a nonzero sigma mem (at least when it is negative) when using SDS methods; otherwise estimators of sigma 2gm and sigma ggm are biased upward and downward, respectively.

A Further Look at Evidence for Cytoplasmic Inheritance of Production Traits in Dairy Cattle

A recent study interpreted significant effects of source of cytoplasm as evidence for cytoplasmic inheritance. An alternative interpretation that observed results reflected residual additive genetic effects unaccounted for by statistical models used was tested by computer simulation of records over 60 yr for milk yield (h2=.30) and fat percentage (h2=.60) under an additive genetic model with no cytoplasmic effects. First lactation records for the last 30 yr were analyzed by least squares according to models that included effects of cytoplasmic source, generations to cytoplasmic source, herd, and year as well as effects of sire (model 1), sire and record of dam (model 2), Predicted Difference of sire (model 3), or Predicted Difference of sire and ½ Predicted Difference of maternal grandsire (model 4). Ten replicates were performed. Significant cytoplasmic effects were observed for all models in at least 8 of 10 replicates for milk yield and in all replicates for fat percentage. Average F ratios for cytoplasmic effects were 1.43, 1.25, 1.46, and 1.43 for milk yield and 2.00, 1.29, 2.04, and 1.96 for fat percentage for models 1, 2, 3, and 4. Cytoplasmic variances were 1.4 and 3.2% of residual variances for milk yield and fat percentage for model 1. Unaccounted for additive genetic effects can produce spurious cytoplasmic effects.

Best Linear Unbiased Prediction with the Reduced Animal Model: An Application to Evaluation of Performance-Tested Males

Best linear unbiased prediction (BLUP) is a powerful method to evaluate genetic values of animals, but the computation is sometimes costly because of the large set of equations to be solved. Equivalent linear models with a reduced number of elements of breeding values can reduce computations substantially. Predictions of additive genetic merit using an animal model and a reduced animal model are described for the case of sire and maternal grandsire and a simple numerical example is used to illustrate the identity of the two solutions. The reduced animal model can be useful for evaluation of males that have been performance-tested and have, in some cases, progeny that have been tested, as is the case with beef cattle.

Evaluation of Corrective Mating for Type Traits in Jersey Cattle

First available appraisals of 14,721 Jersey cows having valid scores for 13 linear type traits, dams with cow indexes for linear traits, and sires and maternal grandsires with Predicted Differences for linear traits, were used to evaluate corrective mating for type traits. Predicted Differences of sires and four measures of merit of dams were used to predict offspring linear trait scores relative to herd average. Measures of dam's merit were phenotypic score relative to the overall mean, phenotypic score relative to herd mean, cow index, and half her sire's Predicted Difference.Regressions of offspring linear scores on a composite pedigree index (sire + dam measure) ranged near 1.0, whereas regressions on measures of sires and dams separately, yielded coefficients for sires that consistently were larger than those for dams. Mean squares and least squares means for measures of dam's merit suggested dam's cow index is superior to dam's phenotypic score for predicting mean score of offspring groups. Frequencies of predicted scores within ±4 points of actual scores ranged from 52% for stature to 80% for udder depth. Correlations between measures of sires and dams indicated little assortative mating has been practiced for linear type traits in Jersey cattle.

Sire and Maternal Grandsire Effects on Calving Difficulty and Calf Mortality in Israeli Holsteins

Associations among sire and maternal grandsire evaluations for calving difficulty and calf mortality were investigated in the Israeli Holstein population. Primiparous and multiparous calvings were analysed separately. Genetic correlations between calving difficulty and calf mortality were close to unity for primiparous calvings but lower for multiparous calvings. Genetic correlations between primiparous and multiparous sire evaluations were .94 and .72 for calving difficulty and calf mortality. Genetic correlations between sire and maternal grandsire evaluations were .6 for primiparous calvings and not-significant for multiparous calvings for both traits. These results correspond to findings that the direct genetic effect is larger than the maternal effect but that there is a slight negative correlation between them.We suggest that sire evaluations for calving difficulty of multiparous cows be used as a preliminary prediction of heifer calving difficulty and calf mortality and that the separate calving trait evaluations be combined into an overall calving selection index.

Relationships Between Sires and Sons for Evaluations from First, All, and Later Records

January 1984 Modified Contemporary Comparison sire evaluations for first, all, and later records were used to create sire-son pairs in five dairy breeds. Each evaluation for each bull included 10 or more daughters. Regressions of son on sire for evaluations for first, all, or later records exceeded the expectation of .5 and were most divergent for Jerseys and Brown Swiss. Regressions and coefficients of determination were generally highest when sire's evaluation based on all records predicted sons’ evaluations from first, all, or later records. Regression of son on sire for difference in evaluations (later minus first) was positive in all breeds, ranging from .08 to .10, and was significant for all breeds except Brown Swiss. Coefficients of determination were low (.01 to .02). Both regression of son on sire for difference and coefficient of determination increased with son's Repeatability, with a regression of .33 and a coefficient of determination of .09 for sons over 99% Repeatability, Regressions for 8,055 Holsteins with evaluations for sires and maternal grandsires on those ancestors were .46 to .54 for sires and .25 to .31 for maternal grandsires. Regressions of son's evaluation on pedigree index were .94 for first, 1.05 for all, and 1.12 for later lactations.