Rate of inbreeding and effective population size in four major South African dairy cattle breeds

Maiwashe, A.; Nephawe, Khathutshelo Agree; Westhuizen, RR Van der; Mostert, B.E.; Theron, HE

doi:10.4314/sajas.v36i1.3986

Cited by 27 publications

(26 citation statements)

References 10 publications

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“…Although there are several criteria to prioritize breeds for conservation programs (Bennewitz and Meuwissen, 2005), the endangerment status of breeds is the most important criterion (Ruane, 2000), which can be expressed in terms of the effective population size. The N e of GSA and GUS population was reported to be higher (165 and 65, respectively) in the past (Weigel, 2001;Maiwashe et al, 2006) than the results observed in this study. This implies a decline in the genetic diversity of the GSA and GUS populations.…”

Section: Discussioncontrasting

confidence: 79%

“…Moreover, the average generation interval for the breeds was about 6 years, which was similar to the report in other breeds, such as, the Canadian Jersey breed (Stachowicz et al, 2011). However, GSA and Ayrshire breeds had longer (6.21 and 6.95, respectively) generation intervals reported (Maiwashe et al, 2006). In conservation programs, the rate of inbreeding is the most important parameter in monitoring genetic diversity in terms of effective population size (Wiggans, 1995).…”

Section: Discussionsupporting

confidence: 78%

“…Moreover, comparable annual rates of inbreeding in US and UK Holsteins (0.20% and 0.17%, respectively) were reported (Wiggans, 1995;Kearney et al, 2004). On the other hand, a lower annual rate of inbreeding (0.05%) for the (GSA) population was reported (Maiwashe et al, 2006). The level of inbreeding in the Canadian dairy population has been increasing gradually and the trend would continue (Sewalem et al, 2006).…”

Section: Discussionmentioning

confidence: 88%

“…Previous studies, however, have demonstrated that rates of increase in inbreeding and estimates of effective population size in dairy cattle populations are alarming (Kearney et al, 2004). In particular, Weigel (2001) and Maiwashe et al (2006) reported that the American (GUS) and South African Guernsey (GSA) populations had effective population sizes of 65 and 165, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Genetic diversity of Guernsey population using pedigree data and gene-dropping simulations

Melka

Sargolzaei

Miglior

et al. 2013

Animal

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The objectives of this study were to analyze the trend of within-breed genetic diversity and identify major causes leading to loss of genetic diversity in Guernsey breed in three countries. Pedigree files of Canadian (GCN), South African (GSA) and American (GUS) Guernsey populations containing 130 927, 18 593 and 1 851 624 records, respectively, were analyzed. Several parameters derived from the in-depth pedigree analyses were used to measure trends and current levels of genetic diversity. Pedigree completeness index of GCN, GSA and GUS populations, in the most recent year (2007), was 97%, 74% and 79%, respectively, considering four generations back in the analysis. The rate of inbreeding in each population was 0.19%, 0.16% and 0.17% between 2002 and 2007, respectively. For the same period, the estimated effective population size for GCN, GSA and GUS was 46, 57 and 46, respectively. The estimated percentage of genetic diversity lost within each population over the last four decades was 8%, 3% and 5%, respectively. The relative proportion of genetic diversity lost due to random genetic drift in the three populations was 93%, 91% and 86%, respectively. In conclusion, the results suggested that GCN and GUS have lost more genetic diversity than GSA over the past four decades, and this loss is gaining momentum due to increasing rates of inbreeding. Therefore, strategies such as optimum contribution selection and migration of genetic material are advised to increase effective population size, particularly in GCN and GUS.

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Section: Discussioncontrasting

confidence: 79%

Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 88%

Section: Introductionmentioning

confidence: 99%

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Genetic diversity of Guernsey population using pedigree data and gene-dropping simulations

Melka

Sargolzaei

Miglior

et al. 2013

Animal

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“…most modern dairy breeds (McAllister, 2002). An accumulation of inbreeding has been reported at a slightly higher rate in the South African (SA) Jersey population compared with other dairy purebreds, (Maiwashe et al, 2006). Du Toit et al (2012) also reported significant negative effects of inbreeding on functional herd life in the first and second lactations of SA Jersey cows.…”

Section: Introductionmentioning

confidence: 99%

Reproductive performance of Jersey and Fleckvieh × Jersey heifers and cows maintained on a pasture-based feeding system

Goni¹,

Muller²,

Dube³

et al. 2015

SA J. An. Sci.

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Crossbreeding is regarded as a faster way than using pure dairy breeds to improve the reproductive performance of dairy cows, which is pivotal to farm income. The reproductive performances of Jersey and Fleckvieh × Jersey (F × J) heifers and cows were compared in a pasture-based production system. Heifers were inseminated when showing signs of heat from 13 months old and cows from 40 days post calving. Using insemination records and pregnancy check results, fertility traits were derived and compared between breeds, using analysis of variance for continuous records. Age at first insemination and conception age for heifers did not differ between the two breeds, resulting in a similar age at first calving. For cows, the mean (± SE) interval from calving to first insemination was shorter for F × J cows, being 76.7 ± 2.2 days compared with 82.4 ± 2.5 days for Jersey cows. A larger proportion of F × J cows were inseminated within 80 days post calving, compared with the Jersey cows (0.70 and 0.54, respectively). Furthermore, the proportion of cows confirmed pregnant by 100 days in milk was higher for F × J cows in comparison with Jersey cows, being 0.79 and 0.66, respectively. Although the absolute number of days between calving and conception (days open) was slightly less for F × J cows in comparison with Jersey cows (104.8 ± 6.8 and 114.8 ± 8.1 days, respectively), the difference was not significant. These results indicate the potential of improving reproductive performance of Jersey cows through crossbreeding with the dual-purpose Fleckvieh.

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Smallholder goat breeding and flock management practices in the central rift valley of Ethiopia

Kebede¹,

Haile

Dadi

2011

Trop Anim Health Prod

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The study was conducted in the central rift valley of Ethiopia to define Arsi-Bale goat keepers' breeding objectives and breeding practices and to describe flock management practices and rate of inbreeding in Arsi-Bale goat population. Two-stage sampling techniques were employed to select study sites and 202 respondents. Semistructured questionnaire and group discussion were used to collect the required information. Data were analyzed using statistical package for social science. Rate of inbreeding in the population and indices were also calculated. On average, each respondent holds around 12 goats in which 30.7, 66.6 and 2.7% were males, females and castrates, respectively. The most important purpose of goat production in the study area was for milk utilization. Farmers have multiple breeding objectives and they considered both subjective and objective selection criteria with slightly more emphasis on morphological characteristics for buck selection than replacement doe selection. Only 39.1% (n = 79) of respondents have their own breeding bucks. None of the respondents practiced controlled mating. Average rate of inbreeding in the population was around 0.20. Arsi-Bale goats are found to be adaptive to the prevailing condition. Therefore, any breed improvement strategy to be designed or implemented in the study area and other similar areas should consider important traditional breeding practices.

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Rate of inbreeding and effective population size in four major South African dairy cattle breeds

Cited by 27 publications

References 10 publications

Genetic diversity of Guernsey population using pedigree data and gene-dropping simulations

Genetic diversity of Guernsey population using pedigree data and gene-dropping simulations

Reproductive performance of Jersey and Fleckvieh × Jersey heifers and cows maintained on a pasture-based feeding system

Smallholder goat breeding and flock management practices in the central rift valley of Ethiopia

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