Genetic Relationships Between Persistency and Reproductive Performance in First-Lactation Canadian Holsteins

Muir, B.L.; Fatehi, J.; Schaeffer, L.R.

doi:10.3168/jds.s0022-0302(04)73435-9

Cited by 113 publications

(167 citation statements)

References 30 publications

(65 reference statements)

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“…However, the genetic correlation between CR and milk yield in third lactation would be affected by selection for culling, because the number of cows evaluated decreased from 262 996 in first lactation to 118 820 in third lactation. Muir et al (2004) reported low positive genetic correlations between lactation persistency and NR at 56 days after first AI during first lactation in heifers and cows. Haile-Mariam et al (2003) reported near-zero genetic associations between lactation persistency and CI in first parity.…”

Section: Discussionmentioning

confidence: 94%

“…This antagonistic relationship has the potential to cause serious problems if breeders select cows mainly on the basis of production traits. Muir et al (2004) suggested that factors that alter the shape of the lactation curve of an individual cow, such as lactation persistency, affect female fertility. However, few studies have focused on the genetic correlations between the CRs of cows and virgin heifers and their test-day (TD) milk yields at various stages of lactation (Veerkamp et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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Relationships between conception rate in Holstein heifers and cows and milk yield at various stages of lactation

Hagiya

Terawaki

Yamazaki

et al. 2013

Animal

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We investigated the relationships between conception rates (CRs) at first service in Japanese Holstein heifers (i.e. animals that had not yet had their first calf) and cows and their test-day (TD) milk yields. Data included records of artificial insemination (AI) for heifers and cows that had calved for the first time between 2000 and 2008 and their TD milk yields at 6 through 305 days in milk (DIM) from first through third lactations. CR was defined as a binary trait for which first AI was a failure or success. A threshold-linear animal model was applied to estimate genetic correlations between CRs of heifers or cows and TD milk yield at various lactation stages. Two-trait genetic analyses were performed for every combination of CR and TD milk yield by using the Bayesian method with Gibbs sampling. The posterior means of the heritabilities of CR were 0.031 for heifers, 0.034 for first-lactation cows and 0.028 for second-lactation cows. Heritabilities for TD milk yield increased from 0.324 to 0.433 with increasing DIM but decreased slightly after 210 DIM during first lactation. These heritabilities from the second and third lactations were higher during late stages of lactation than during early stages. Posterior means of the genetic correlations between heifer CR and all TD yields were positive (range, 0.082 to 0.287), but those between CR of cows and milk yields during first or second lactation were negative (range, 20.121 to 20.250). Therefore, during every stage of lactation, selection in the direction of increasing milk yield may reduce CR in cows. The genetic relationships between CR and lactation curve shape were quite weak, because the genetic correlations between CR and TD milk yield were constant during the lactation period.

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Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Relationships between conception rate in Holstein heifers and cows and milk yield at various stages of lactation

Hagiya

Terawaki

Yamazaki

et al. 2013

Animal

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“…If the lactation of a cow is more persistent, the lactation curve is flatter, with a lower and later peak. As a consequence, a cow with a flatter lactation curve is exposed to less stress due to high peak production, and the incidence of reproductive and metabolic disorders may be reduced to some extent (Gengler et al 1995;Muir et al 2004). Measuring lactation persistency by one single term is difficult, so persistency has been defined in many ways (Solkner and Fuchs 1987;Swalve 1994;Gengler et al 1995;Muir et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Genetic relationship between lactation persistency and conformation traits in Polish Holstein-Friesian cow population

Otwinowska-Mindur¹,

Ptak²,

Jagusiak³

2016

CZECH J ANIM SCI

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ABSTRACT:The objective of this study was to find genetic relationships between lactation persistency and conformation traits of Polish Holstein-Friesian cows. The data were derived from SYMLEK -the Polish National Database. The analysis used 22 conformation traits and 3 persistency measures of 18 216 first lactation cows. Persistency was defined as milk yield in the second 100 days in milk (DIM) divided by the yield in the first 100 DIM, milk yield in the third 100 DIM divided by the yield in the first 100 DIM, and milk yield at 280 DIM divided by milk yield at 60 DIM. The lactation curve was modelled with fourth-order Legendre polynomials using a multiple-trait prediction method. The multiple-trait REML method was applied for (co)variance component estimation. The linear model for persistency included fixed effects of herd-year-season of calving, age of calving class, and random animal effect; the linear model for type traits included fixed effects of herd-year-season of calving-classifier, age of calving class, lactation stage, and random animal effect. Stature and composite type traits (except type and conformation) were moderately or strongly genetically correlated with each of the three persistency measures. Genetic correlations of lactation persistency with overall feet and leg score and overall udder score were high and positive, whereas the correlations with stature and size were high but negative. All linearly scored traits had little genetic relationship with persistency measures except for rear udder height, udder width, and foot angle. In these three cases the genetic correlations with persistency measures were relatively high, positive, and preferable. The obtained genetic correlations suggest that increased weights of composite traits like size, overall feet and leg score, and overall udder score in the selection index, as well as selection for better rear udder height and foot angle, might cause a favourable correlated response in persistency.

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“…total mixed ration) and superior genotypes. The potential to select genotypes for lactation persistency was illustrated by Muir et al (2004), who estimated lactation persistency in first lactation Canadian Holstein Friesians was moderately heritable (h 2 ¼ 0.18).…”

Section: Discussionmentioning

confidence: 99%

The effect of level of feeding, genetic merit, body condition score and age on biological parameters of a mammary gland model

Bryant

López‐Villalobos

Holmes

et al. 2007

Animal

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An evolutionary algorithm was applied to a mechanistic model of the mammary gland to find the parameter values that minimised the difference between predicted and actual lactation curves of milk yields in New Zealand Jersey cattle managed at different feeding levels. The effect of feeding level, genetic merit, body condition score at parturition and age on total lactation yields of milk, fat and protein, days in milk, live weight and evolutionary algorithm derived mammary gland parameters was then determined using a multiple regression model. The mechanistic model of the mammary gland was able to fit lactation curves that corresponded to actual lactation curves with a high degree of accuracy. The senescence rate of quiescent (inactive) alveoli was highest at the very low feeding level. The active alveoli population at peak lactation was highest at very low feeding levels, but lower nutritional status at this feeding level prevented high milk yields from being achieved. Genetic merit had a significant linear effect on the active alveoli population at peak and mid to late lactation, with higher values in animals, which had higher breeding values for milk yields. A type of genetic merit £ feeding level scaling effect was observed for total yields of milk and fat, and total number of alveoli produced from conception until the end of lactation with the benefits of increases in genetic merit being greater at high feeding levels. A genetic merit £ age scaling effect was observed for total lactation protein yields. Initial rates of differentiation of progenitor cells declined with age. Production levels of alveoli from conception to the end of lactation were lowest in 5-to 8-year-old animals; however, in these older animals, quiescent alveoli were reactivated more frequently. The active alveoli population at peak lactation and rates of active alveoli proceeding to quiescence were highest in animals of intermediate body condition scores of 4.0 to 5.0. The results illustrate the potential uses of a mechanistic model of the mammary gland to fit a lactation curve and to quantify the effects of feeding level, genetic merit, body condition score, and age on mammary gland dynamics throughout lactation.

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Genetic Relationships Between Persistency and Reproductive Performance in First-Lactation Canadian Holsteins

Cited by 113 publications

References 30 publications

Relationships between conception rate in Holstein heifers and cows and milk yield at various stages of lactation

Relationships between conception rate in Holstein heifers and cows and milk yield at various stages of lactation

Genetic relationship between lactation persistency and conformation traits in Polish Holstein-Friesian cow population

The effect of level of feeding, genetic merit, body condition score and age on biological parameters of a mammary gland model

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