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Genetic Correlations Among Progeny Groups for Type Traits, Milk Yield, Yield Persistency, and Culling Rates
Genetic Correlations Among Progeny Groups for Type Traits, Milk Yield, Yield Persistency, and Culling Rates R. B A R - A N A N and M. RON Institute of Animal Science Agricultural Research Organization, The Volcani Center Bet Dagan 50250, Israel
kilograms 3.3% economically fat-corrected milk (ECM), percent yield persistency, and percent culling rate. F a t corrections for ECM were on ratio kilograms milk:fat price of 1:10; kilograms ECM = .67 × kilograms milk + 10 x kilograms fat. Yields of ECM were corrected for age and month of calving and for days open (1). Yield persistency (P) was estimated as:
ABSTRACT
Associations among six primipara type traits and first and second lactation milk yield, yield persistency, and culling rates were estimated by means of 100 progeny groups with first and 76 with second lactations. Correlations of second lactation culling rate with dairy character and with rear udder were approximately - . 4 . Persistency, measured in either first or second lactation, was negatively associated with all t y p e traits.
P = L/(dS)
INTRODUCTION
Type in Israel has been appraised for 15 yr and is limited to primiparous daughters of test bulls and to dams of bulls. Purposes of classification have been to evaluate visually groups of daughters with the hope of predicting transmitting abilities of their sires for type constitution and production. The objective of this study was to evaluate the association between primiparous type traits and production characteristics of progeny groups. MATERIALS AND METHODS
The material consisted of mean primipara type ratings and first and second lactation data of progeny groups. Daughters were inspected by a breeding panel of the "ON" AI Association during the initial part of their heifer lactation. Six traits were recorded: dairy character (DC), size (SI), body build: feet, legs, shoulders (BB), fore udder (FU), rear udder (RU), and teat conformation (TC). For each trait five scores from 5 to 9 were given. Yield traits were estimated by the national dairy cattle progeny test scheme and consisted of separate first and second lactation Predicted Difference (PD) for
where, L = lactation yield, d = days between calvings, and S = summit yield. The S is mean kg ECM of the two highest m o n t h l y recordings within 95 days postpartum. Gulling rates (CR) were proportions of cows culled for low yield, mastitis, and infertility among the number calved. The PD for ECM was estimated by a fixed base (2) and for P and CR by within-lactation/herd/year/season contemporary comparison (7). The PD for type was estimated with h 2 = .2 for all traits (4). In the correlation estimates only daughter-groups of >.6 repeatability for each of the type and production characteristics were included. Product-moment correlations (r) between PD type and production characteristics were obtained. There were 100 daughter groups for correlations with first and 76 with second lactation production. Genetic correlations were estimated from the correlations calculated between PD following the suggestion by Calo et al. (3): 9gl,2 =rl,2 ( ~ R l i ~ i ~
R2i)'s/(G
1
RliR2i)
where ^rgl, 2 = genetic correlation, and R l i , R2i = repeatability coefficients for sire i and traits 1 and 2, respectively. RESULTS A N D DISCUSSION
Received September 15, 1982. 1983 J Dairy Sci 66:2438-2440
Primipara SI, DC, FU, RU, and TC were positively associated with first lactation ECM 2438
TABLE 1. Correlation between primipara type traits and yields, yield persistency, and culling rate. I Kg ECM 2 1st lact
Size Dairy character Body build Fore udder Rear udder Teats Kg ECM, 1st lact
c-
Culling rate
Persistency 2nd lact
2nd lact
1st lact
2nd lact
1st lact
rpD 3
rg 4
rpD
rg
rpD
rg
rpD
rg
rpD
rg
rpD
rg
.14 .13 -.05 .02 .16 .15
.18 .16 -.06 .02 .20 .19
.07 .16 -.09 -.04 .14 .03 .60**
.09 .20 -.11 -.05 .18 .03 .77
-.14 --.14 -.14 -.25** -.05 --.17 .24*
-.18 --.18 -.18 -.32 -.06 --.21 .30
-.19 --.23* -.21 -.22* -.18 --.26* .25*
-.24 --.29 -.27 -.28 -.23 --.33 .32
.02 --.06 .15 -.07 -.06 .04 --.44**
.02 --.07 .19 -.09 -.07 .05 --.56
.12 -.32** -.10 -.11 -.33** --.16 --.25*
.15 -.41 -.12 -.13 -.42 --.20 --.32
Z > r~ Z ©
1100 sires with 1st, 76 with 2nd lactation (lact) yields. ~Kg ECM = .67 × kg milk + 10 X kg fat.
o
3 rp D = Correlations between Predicted Differences (PD). 4 rg = Genetic correlations estimated from rpD. * Statistical significance at 5% of rpD.
g
**Statistical significance at 1% of rpD.
< o
Z
o
t~ ta~ xO taa
2440
BAR-ANAN AND RON
(Table 1). The positive correlations for R U and yield were n o t in accord with (5). A possible explanation m a y be that our data were f r o m primiparas for which milk p r o d u c t i o n has n o t yet affected udder c o n f o r m a t i o n . Each of the primipara t y p e traits was negatively associated with yield persistency within first and within second lactations, although there was a positive correlation b e t w e e n yield and persistency. The m u l t i p l e square of correlations (R 2) among the six t y p e traits and yield persistency in first and second lactations were .18 and .15. The usefulness of t y p e traits for predicting yield traits appears limited in view of the low correlations between pairs of traits (Table 1). All correlations between t y p e traits and ECM (first or second lactations) were n o t significant. F o u r of 12 correlations were significant b e t w e e n t y p e traits and persistency, and all 12 were negative and unfavorable. The findings support the c o n t e n t i o n of Hickman (6) that physiological bases for early and late lactation yields are different. It appears that high scoring cows (at early stages of lactation) are not capable of maintaining persistency by resisting the stress of lactation. Associations b e t w e e n DC and R U with second lactation CR were significantly negative. Thus, DC and R U were markers for second lactation culling.
Journal of Dairy Science Vol. 66, No. 11, 1983
ACKNOWLEDGMENTS
This investigation was supported by the U.S.-Israel Binational Agricultural Research and D e v e l o p m e n t F u n d (BARD), Project No. 1--3--79; c o n t r i b u t i o n f r o m the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel No. 554-E, 1982 series. REFERENCES
1 Bar-Anan, R., H. Krausslich, and K. Osterkorn, 1981. Parameters of yield characters in Israeli dairy herds. Refu. Vet. 38:17. 2 Bar-Anan, R., M. Ron, and G. R. Wiggans, 1983. Associations among progeny tests of single or pooled lactations. J. Dairy Sci. 66:595. 3 Calo, L. L., R. E. McDowell, L. D. Van Vleck, and P. D. Miller, 1973. Genetic aspects of beef production among pedigree Holstein-Friesians selected for milk production. J. Anita. Sci. 37:676. 4 Cassell, B. G., J. M. White, W. E. Winson, and R. H. Kliewer, 1973. Genetic and phenotypic relationships among type traits in Holstein-Friesian cattle. J. Dairy Sci. 56:1171. 5 Grantham, J. A., J. M. White, W. E. Vinson, and R. H. Kliewer. 1974. Genetic relationships between milk production and type in Holsteins. J. Dairy Sci. 57:1483. 6 Hickman, C. G. 1980. Physiological effects of selection for milk yield A. Robertson, ed. Selection experiments in laboratory and domestic animals. Commonw. Agric. Bur., U.K. 7 Robertson, A., and I. M. Rendel. 1954. The performance by heifers got by artificial insemination. J. Agric. Sci., Camb. 44:184.
kilograms 3.3% economically fat-corrected milk (ECM), percent yield persistency, and percent culling rate. F a t corrections for ECM were on ratio kilograms milk:fat price of 1:10; kilograms ECM = .67 × kilograms milk + 10 x kilograms fat. Yields of ECM were corrected for age and month of calving and for days open (1). Yield persistency (P) was estimated as:
ABSTRACT
Associations among six primipara type traits and first and second lactation milk yield, yield persistency, and culling rates were estimated by means of 100 progeny groups with first and 76 with second lactations. Correlations of second lactation culling rate with dairy character and with rear udder were approximately - . 4 . Persistency, measured in either first or second lactation, was negatively associated with all t y p e traits.
P = L/(dS)
INTRODUCTION
Type in Israel has been appraised for 15 yr and is limited to primiparous daughters of test bulls and to dams of bulls. Purposes of classification have been to evaluate visually groups of daughters with the hope of predicting transmitting abilities of their sires for type constitution and production. The objective of this study was to evaluate the association between primiparous type traits and production characteristics of progeny groups. MATERIALS AND METHODS
The material consisted of mean primipara type ratings and first and second lactation data of progeny groups. Daughters were inspected by a breeding panel of the "ON" AI Association during the initial part of their heifer lactation. Six traits were recorded: dairy character (DC), size (SI), body build: feet, legs, shoulders (BB), fore udder (FU), rear udder (RU), and teat conformation (TC). For each trait five scores from 5 to 9 were given. Yield traits were estimated by the national dairy cattle progeny test scheme and consisted of separate first and second lactation Predicted Difference (PD) for
where, L = lactation yield, d = days between calvings, and S = summit yield. The S is mean kg ECM of the two highest m o n t h l y recordings within 95 days postpartum. Gulling rates (CR) were proportions of cows culled for low yield, mastitis, and infertility among the number calved. The PD for ECM was estimated by a fixed base (2) and for P and CR by within-lactation/herd/year/season contemporary comparison (7). The PD for type was estimated with h 2 = .2 for all traits (4). In the correlation estimates only daughter-groups of >.6 repeatability for each of the type and production characteristics were included. Product-moment correlations (r) between PD type and production characteristics were obtained. There were 100 daughter groups for correlations with first and 76 with second lactation production. Genetic correlations were estimated from the correlations calculated between PD following the suggestion by Calo et al. (3): 9gl,2 =rl,2 ( ~ R l i ~ i ~
R2i)'s/(G
1
RliR2i)
where ^rgl, 2 = genetic correlation, and R l i , R2i = repeatability coefficients for sire i and traits 1 and 2, respectively. RESULTS A N D DISCUSSION
Received September 15, 1982. 1983 J Dairy Sci 66:2438-2440
Primipara SI, DC, FU, RU, and TC were positively associated with first lactation ECM 2438
TABLE 1. Correlation between primipara type traits and yields, yield persistency, and culling rate. I Kg ECM 2 1st lact
Size Dairy character Body build Fore udder Rear udder Teats Kg ECM, 1st lact
c-
Culling rate
Persistency 2nd lact
2nd lact
1st lact
2nd lact
1st lact
rpD 3
rg 4
rpD
rg
rpD
rg
rpD
rg
rpD
rg
rpD
rg
.14 .13 -.05 .02 .16 .15
.18 .16 -.06 .02 .20 .19
.07 .16 -.09 -.04 .14 .03 .60**
.09 .20 -.11 -.05 .18 .03 .77
-.14 --.14 -.14 -.25** -.05 --.17 .24*
-.18 --.18 -.18 -.32 -.06 --.21 .30
-.19 --.23* -.21 -.22* -.18 --.26* .25*
-.24 --.29 -.27 -.28 -.23 --.33 .32
.02 --.06 .15 -.07 -.06 .04 --.44**
.02 --.07 .19 -.09 -.07 .05 --.56
.12 -.32** -.10 -.11 -.33** --.16 --.25*
.15 -.41 -.12 -.13 -.42 --.20 --.32
Z > r~ Z ©
1100 sires with 1st, 76 with 2nd lactation (lact) yields. ~Kg ECM = .67 × kg milk + 10 X kg fat.
o
3 rp D = Correlations between Predicted Differences (PD). 4 rg = Genetic correlations estimated from rpD. * Statistical significance at 5% of rpD.
g
**Statistical significance at 1% of rpD.
< o
Z
o
t~ ta~ xO taa
2440
BAR-ANAN AND RON
(Table 1). The positive correlations for R U and yield were n o t in accord with (5). A possible explanation m a y be that our data were f r o m primiparas for which milk p r o d u c t i o n has n o t yet affected udder c o n f o r m a t i o n . Each of the primipara t y p e traits was negatively associated with yield persistency within first and within second lactations, although there was a positive correlation b e t w e e n yield and persistency. The m u l t i p l e square of correlations (R 2) among the six t y p e traits and yield persistency in first and second lactations were .18 and .15. The usefulness of t y p e traits for predicting yield traits appears limited in view of the low correlations between pairs of traits (Table 1). All correlations between t y p e traits and ECM (first or second lactations) were n o t significant. F o u r of 12 correlations were significant b e t w e e n t y p e traits and persistency, and all 12 were negative and unfavorable. The findings support the c o n t e n t i o n of Hickman (6) that physiological bases for early and late lactation yields are different. It appears that high scoring cows (at early stages of lactation) are not capable of maintaining persistency by resisting the stress of lactation. Associations b e t w e e n DC and R U with second lactation CR were significantly negative. Thus, DC and R U were markers for second lactation culling.
Journal of Dairy Science Vol. 66, No. 11, 1983
ACKNOWLEDGMENTS
This investigation was supported by the U.S.-Israel Binational Agricultural Research and D e v e l o p m e n t F u n d (BARD), Project No. 1--3--79; c o n t r i b u t i o n f r o m the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel No. 554-E, 1982 series. REFERENCES
1 Bar-Anan, R., H. Krausslich, and K. Osterkorn, 1981. Parameters of yield characters in Israeli dairy herds. Refu. Vet. 38:17. 2 Bar-Anan, R., M. Ron, and G. R. Wiggans, 1983. Associations among progeny tests of single or pooled lactations. J. Dairy Sci. 66:595. 3 Calo, L. L., R. E. McDowell, L. D. Van Vleck, and P. D. Miller, 1973. Genetic aspects of beef production among pedigree Holstein-Friesians selected for milk production. J. Anita. Sci. 37:676. 4 Cassell, B. G., J. M. White, W. E. Winson, and R. H. Kliewer, 1973. Genetic and phenotypic relationships among type traits in Holstein-Friesian cattle. J. Dairy Sci. 56:1171. 5 Grantham, J. A., J. M. White, W. E. Vinson, and R. H. Kliewer. 1974. Genetic relationships between milk production and type in Holsteins. J. Dairy Sci. 57:1483. 6 Hickman, C. G. 1980. Physiological effects of selection for milk yield A. Robertson, ed. Selection experiments in laboratory and domestic animals. Commonw. Agric. Bur., U.K. 7 Robertson, A., and I. M. Rendel. 1954. The performance by heifers got by artificial insemination. J. Agric. Sci., Camb. 44:184.