Genetic control of reproduction and lactation in ruminants<sup>1</sup>

Maijala, Kalle

doi:10.1111/j.1439-0388.1987.tb00109.x

Cited by 4 publications

(2 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In previous studies heritability estimates were generally weak and ranged from 0.01 to 0.05 (Maijala, 1987;Hanset et al, 1989b) using a linear model. However, genetic improvement of reproductive traits is very hard to achieve due to their low heritability.…”

Section: Resultsmentioning

confidence: 95%

Phenotypic and genetic parameters of reproductive traits in Tunisian Holstein cows

M’Hamdi¹,

Aloulou²,

Brar³

et al. 2010

Bio Anim Husb

View full text Add to dashboard Cite

Various factors influencing reproduction in dairy Holstein cows were routinely evaluated and genetic parameters were estimated for four traits to assess fertility of artificially inseminated cows: Calving to first service interval (CFSI), calving interval (CI), calving to conception interval (CCI) and number of services per conception (NSC). Data used in this investigation consisted of records of insemination and calving events on Tunisian Holstein cows. The data included records from 1994 to 2003 in 150 herds. The aim of the study was to investigate the effects of non-genetic factors on reproductive traits and estimate their heritabilities. The factors examined were: month and year of calving, herd, parity, and year-month of calving. The effect of month and year of calving (or insemination), herd, parity and year-month of calving were included in the model and were significant (P < 0.01) except for the number of lactations that does not have an effect on the NSC. A decreasing efficiency in cow fertility was observed over the last years, with a longer day for first service interval. Heritability for fertility traits was low ranging from 0.027 for NSC to 0.067 for CI. The results suggested that more attention should be paid to herds with too low fertility traits and that monitoring and intervention schemes should be tested in research approaches.Key words: fertility traits, genetic parameters, non-genetic factors, Tunisian Holstein RESUMEN Se evaluaron de manera rutinaria diferentes factores que influyen en la reproducción de las vacas lecheras Holstein y se estimaron los parámetros genéticos de cuatro caracteres para evaluar la fertilidad de las vacas inseminadas artificialmente: el intervalo de parto a primer servicio (IPPS), el intervalo entre partos (IP), el intervalo de parto a concepción (IPC) y el número de servicios por concepción (NSC). Los datos utilizados en esta investigación consistieron de registros de eventos de inseminación y partos en vacas Holstein de Túnez. Los registros fueron tomados desde 1994 hasta 2003 en 150 rebaños para estudiar los efectos de factores no genéticos y estimar las heredabilidades de los caracteres anteriormene señalados de fertilidad. Los factores examinados fueron: mes y año de parto, rebaño, paridad y año-mes de parto. El efecto del mes y año de parto (o inseminación), rebaño, paridad y año-mes de parto se incluyeron en el modelo y fueron significativos (P <0,01) con excepción del número de lactancias que no tiene un efecto sobre el NSC. Se observe una eficiencia decreciente en la fertilidad de las vacas en los últimos años, con un día más largo para el intervalo del primer servicio. La heredabilidad para los caracteres de la fertilidad fue baja en un rango de 0,027 para NSC a 0,067 para el interval entre partos. Los resultados sugieren que debería prestarse más atención a los rebaños con rasgos muy bajos de fertilidad y que los esquemas de vigilancia e intervención deberían ser evaluados con enfoques de investigación, Palabras clave: Caracteres de fertilidad, pa...

show abstract

Section: Resultsmentioning

confidence: 95%

Phenotypic and genetic parameters of reproductive traits in Tunisian Holstein cows

M’Hamdi¹,

Aloulou²,

Brar³

et al. 2010

Bio Anim Husb

View full text Add to dashboard Cite

show abstract

“…The potential of this variability has not been considered by many researchers on account of the low h 2 value. According to Maijala (1987) this is a pessimistic point of view regarding the possibilities of genetic improvement for fertility traits. For DO; and CI i there was a clear reducing h 2 pattern when the number of calving increased.…”

Section: Discussionmentioning

confidence: 99%

Genetic and environmental factors affecting some reproductive traits of Holstein cows in Cuba

Buxadera¹,

Dempfle²

1997

Genet. Sel. Evol.

View full text Add to dashboard Cite

A total of 226 651 fertility records of dairy cows obtained from 1980 to 1988 was studied in order to determine the environmental and genetic factors affecting the reproductive performance of Holstein cows under Cuban conditions. Only 43.9% of the inseminated females were pregnant at first service; however, for heifers this value was 63.1%. The seasonal variability was higher for heifers and for primiparous than for older lactating cows. The best performance was found from February to April, whereas during the hot and humid summer (July to September) poorer results were obtained.Age at calving or number of calvings was another important environmental source of variation: the earlier the calving the poorer is the next reproductive performance. The genetic analyses were made within calving number with the REML procedure. For heifers (226 sires, 45 575 records) the heritability and the genetic coefficient of variation were: 2.26 and 10.94%, 3.24 and 11.24%, and 3.04 and 6.19% for conception rate (CR), numbers of services per conception (SG) and conception status (CS = 1/SG), respectively. For first calving females (280 sires, 43 647 records) the results were: 1.94 and 15.93%, 3.25 and 12.80%, and 3.47 and 9.47% for CR, SG and CS, respectively. For the second and third calving, the results were poorer. For the calving interval and days open, the heritabilities were between 1.86 and 4.64%. The results of SG were selected as the best and more useful traits showing high genetic correlations (> 0.60) for the same traits in different calving number. Holstein cattle breed / reproduction traits / genetic parameters / tropical conditions Résumé -Facteurs génétiques et environnementaux intervenant sur les performances de reproduction des vaches Holstein à Cuba. Au total 226 651 enregistrements de fertilité de vaches laitières obtenus de 1980 à 1988 sont analysés en vue de déterminer les Correspondence and reprints: F M6nissier, Station de g6n6tique quantitative et appliqu6e, Inra, 78352 Jouy-en-Josas cedex, France facteurs génétiques et environnementaux intervenant sur les performances de reproduction de vaches Holstein dans les conditions cubaines. Seulement 43,9 % des femelles inséminées sont gestantes à la première insémination, alors que pour les génisses ce taux est de 63,1 %. La variabilité due à la saison apparaît plus élevée chez les génisses et primipares que chez les vaches plus âgées. Les meilleurs résultats sont obtenus de février à avril, alors que les plus mauvais sont observés durant l'été (juillet à septembre), qui est chaud et humide dans les conditions cubaines. L'âge au vêlage et le rang de vêlage sont aussi d'importantes sources environnementales de variation. Plus le vêlage est précoce, plus la reproduction suivante est mauvaise. Les analyses génétiques ont été réalisées intrarang de vêlage en utilisant une méthode REML. Pour les génisses (226 pères, 45 575 performances), les héritabilités et coefficients de variation génétiques sont de 2,26 et 10,9l, %, de 3,24 et 11,24 % et de 3,04 et 6,19 % respective...

show abstract

Relationships Between Reproduction Traits, Age and Body Weight at Calving, and Days Dry in First Lactation Ayrshires and Holsteins

Moore

Kennedy

Schaeffer

et al. 1990

Journal of Dairy Science

View full text Add to dashboard Cite

Individual cow test day records collected between December 1979 and June 1986 were used to calculate measures of reproductive performance, age and weight at calving, and days dry for 7824 Ayrshire and 79,755 Holstein cows in first lactation. Separate analyses by breed were carried out according to a multiple-trait mixed model. Sixty-two Ayrshire and 369 Holstein sires were treated as random in the analyses. Ayrshires were, on average, older and lighter at calving than Holsteins, but the breeds differed little in reproduction measures and days dry. Heritabilities of fertility traits, days to first breeding, days open, and services per conception were all less than .015 in the multi-trait analyses. With the exception of body weight, heritability estimates for the other traits were less than .05. Phenotypic correlations between traits were almost identical for the two breeds, and genetic correlations tended to be similar. Exceptions involved the trait days to first breeding and services per conception, but heritabilities of these traits were close to zero (p less than .008) in Ayrshires. Fertility traits were positively correlated genetically. Genetic correlations between days open and both age and body weight at calving were small. The genetic correlation between age and weight at calving was -.90 and -.68 in Ayrshires and Holsteins, respectively. Genetic correlations between days dry and all traits except body weight were moderate and positive.

show abstract

Genetic control of reproduction and lactation in ruminants¹

Cited by 4 publications

References 28 publications

Phenotypic and genetic parameters of reproductive traits in Tunisian Holstein cows

Phenotypic and genetic parameters of reproductive traits in Tunisian Holstein cows

Genetic and environmental factors affecting some reproductive traits of Holstein cows in Cuba

Relationships Between Reproduction Traits, Age and Body Weight at Calving, and Days Dry in First Lactation Ayrshires and Holsteins

Contact Info

Product

Resources

About

Genetic control of reproduction and lactation in ruminants1

Cited by 4 publications

References 28 publications

Phenotypic and genetic parameters of reproductive traits in Tunisian Holstein cows

Phenotypic and genetic parameters of reproductive traits in Tunisian Holstein cows

Genetic and environmental factors affecting some reproductive traits of Holstein cows in Cuba

Relationships Between Reproduction Traits, Age and Body Weight at Calving, and Days Dry in First Lactation Ayrshires and Holsteins

Contact Info

Product

Resources

About

Genetic control of reproduction and lactation in ruminants¹