Generation intervals in Canadian dairy cattle herds

Hagan, Bernard Ato; Cue, R.I.

doi:10.1139/cjas-2019-0053

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…In dairy cattle, Melka et al (2013) reported, for five specialized breeds in Canada, GIs ranging from 3.64 to 6.63 years, with an average of 5.03 years. Hagan and Cue (2020) evaluated the behavior of the GI overtime in four specialized breeds. At the beginning, they observed GIs ranging from 4.5 to 12 years; after 25 years, the GIs ranged from 3.5 to 6.0 years.…”

Section: Resultsmentioning

confidence: 99%

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Pedigree Analysis and Population Structure of Brahman Cattle From Costa Rica

Vásquez-Loaiza¹,

Cruz-Méndez²,

Castro-Vásquez³

et al. 2021

Chil. j. agric. anim. sci.

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The objective of this study was to evaluate the population of Brahman cattle from Costa Rica. Pedigree analysis of 98,749 animals was used to estimate the following parameters: pedigree integrity, as a proportion of known ancestors; the number of complete generations, maximum generations traced, and equivalent complete generations; inbreeding coefficient (F); generation interval (GI) across four selection paths; additive genetic relationship (AGR); effective number of founders (fe) and ancestors (fa); and effective population size (Ne). The analysis was carried out using the ENDOG software. The maximum proportions of unknown parents, grandparents, and great-grandparents were 14.1%, 38.9%, and 61.2%, respectively. Average F for the whole population was 0.86, while 27.4% of the population was inbred, with an average F of 3.1%. The inbred population increased through the time, while F decreased. The average AGR was 0.64, with maximum values of 4.1 and positive trends. The fe and fa were 617.8 and 172.0, respectively. The Ne indicated increases of F, with values lower than 1%. The GI fluctuated from 6.4 to 7.4, with an average of 6.85 years. These results summarize previous breeding practices and represent useful information for designing breeding programs by anticipating the relationship between the selection response and increases of inbreeding.

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Section: Resultsmentioning

confidence: 99%

“…The GI was determined using the mean age of a reproductive animal, at which it is replaced by one of its offspring. The GI was calculated using the four selection paths: father -son, father -daughter, mother -son, and mother -daughter (Ramírez-Valverde et al, 2018;Hagan and Cue, 2020).…”

Section: Methodsmentioning

confidence: 99%

Pedigree Analysis and Population Structure of Brahman Cattle From Costa Rica

Vásquez-Loaiza¹,

Cruz-Méndez²,

Castro-Vásquez³

et al. 2021

Chil. j. agric. anim. sci.

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“…The GI was determined using the mean age of a reproductive animal, at which it is replaced by one of its offspring. The GI was calculated using the four selection paths: father -son, father -daughter, mother -son, and mother -daughter (RAMÍREZ-VALVERDE et al, 2018;HAGAN & CUE, 2019). Based on the GI calculations, the period that includes the analyzed information was divided into generations.…”

Section: Methodsmentioning

confidence: 99%

Structure and genetic variability of the Mexican Sardo Negro breed

et al. 2022

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This study analyzed the Sardo Negro breed pedigree (41,521 animals registered from 1958 to 2019) to determine its structure, evolution, and genetic variability (GV). The population genetic parameters evaluated were effective number of founders (fe) and ancestors (fa), pedigree integrity, additive genetic relationship (AGR); number of complete generations (NCG), maximum generations traced (NMGT), and equivalent complete generations (NECG); effective population size (Ne), inbreeding coefficient (F), and generation interval (GI). The average GI was 7.45 years. A total of 7,804 founders and 4,856 ancestors were identified for a fe of 185 and a fa of 97. The average and maximum values of NCG, NECG, and NMGT were 1.6 and 5.0, 2.5 and 6.5, 4.3 and 12, with Ne estimates of 15.9, 25.9, and 69.0, respectively. The increase in F, linked to Ne, ranged from 0.72% to 3.1% per generation. The average values for F and AGR were 3.6% and 1.0%, respectively. The proportion of inbred individuals was 32.0%, with F values ranging from 0.01 to 62.2% and an average of 11.3%. The rate of inbred population was 1.3% per year. The annual rate of AGR was 0.04%. For the continuity and projection of the breed, the evolution of F as a function of Ne and the possible implications of the selection schemes must be considered. The genetic variability sustained over time results from the Ne.

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“…Results of the study indicate that genomically evaluated sires used in Ukraine have significantly higher breeding values for milk production traits than sires with traditional evaluations. Reason is faster genetic progress resulting from shorter generation intervals with genomic selection (Hagan & Cue, 2019).…”

Section: Breed Dams Daughtersmentioning

confidence: 99%

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Generation intervals in Canadian dairy cattle herds

Cited by 6 publications

References 16 publications

Pedigree Analysis and Population Structure of Brahman Cattle From Costa Rica

Pedigree Analysis and Population Structure of Brahman Cattle From Costa Rica

Structure and genetic variability of the Mexican Sardo Negro breed

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