Assessment of the genetic variability using pedigree analysis of the Sahiwal breed in Kenya

Summary Pedigree analysis using genealogical information of 18 315 animals born between 1949 and 2008 was done to quantify genetic variability of the Sahiwal population in Kenya. Generation intervals for sire pathways were longer than dam pathways and increased over year periods, from about 4–16 years. The later was due to use of old bulls for breeding in the last 2 year groups and cessation of progeny testing in the year 2000. Average inbreeding level in last year period studied was 1.2 percent. Genetic variability of the population as assessed based on gene origin statistics decreased over the years. The ratio of effective number of founders to founders of 0.06 showed unequal contribution of founders to the reference population. However, since the founding population, ancestors contributed equally as shown by the ratio of f e/f a of 0.94, which could also be due to lack of effective selection in this population. The ratio of f g/f a of 0.63 indicated genetic loss of genetic variability occurred through genetic drift in the Kenyan Sahiwal population. The small number of ancestors (16) that accounted for 50 percent of the total variation in the reference population suggested overuse of a small number of some animals as parents over generations. The smaller ratio of f g/f e compared with f a/f e also confirms loss of genetic variability in the population by genetic drift than bottlenecks. Therefore the breeding strategy for the Sahiwal population in Kenya should incorporate tools that balance rate of genetic gain and the future rate of inbreeding.

Reproductive parameters of some native bovine breeds: Sanmartinero and Casanareño

Resumen En bovinos, la reducción de la eficiencia reproductiva de los sistemas de producción de carne y doble propósito se atribuye a factores nutricionales, sanitarios, climáticos y en última instancia a características genéticas de los animales. Sin embargo, en condiciones de trópico cálido húmedo, variaciones genéticas entre razas podrían reducir la edad al primer parto, el intervalo entre partos y aumentar la vida útil de las vacas. Las razas Sanmartinero y Casanareño podrían mejorar los sistemas de producción bovina debido al aporte de variantes genéticas que emergieron en el proceso de adaptación a las duras condiciones de la Orinoquía Colombiana. Actualmente, los genes con función biológica conocida se usan como marcadores moleculares para estimar parámetros de diversidad genética pecuaria facilitando la identificación y ubicación dentro del genoma de regiones que codifican o regulan la expresión de rasgos de interés económico. En ganado criollo colombiano Romosinuano se han identificado genes candidatos del eje Hormona de crecimiento/Factor de crecimiento similar a la insulina que se asocian positivamente con edad al primer parto, intervalo entre partos, longevidad y protección del embrión al estrés calórico. No obstante en las razas criollas Sanmartinero y Casanareño reconocidas empíricamente por estas características, no han sido sometidas a dichos análisis de genes candidatos que permitan promover un valor agregado a los animales. El objetivo de esta revisión es documentar algunos parámetros reproductivos y genéticos de las razas criollas Sanmartinero y Casanareño que soportan la necesidad de desarrollar estudios moleculares y justificar su uso en los sistemas de producción de carne y doble propósito de la Orinoquía colombiana.

Multivariate analysis for morphological traits of the Hamra goat population in two regions of Morocco

SummaryThe goal of this study was to characterize the Hamra goat population and to determine if Hamra goats of Beni Arouss and Rommani regions belong to the same population. Eleven morphometric traits of 157 Hamra animals (94 from Beni Arouss and 63 from Rommani) were used for this study. Overall, heart girth, body length, height at withers (HaW), height at rump (HS), chest depth (ChD), pelvis width (PW), chest width (CW), cannon circumference, head length (HeL), head width (HeW) and horn length (HL) of Hamra goats averaged 81.3, 61.5, 64.8, 65.3, 40.9, 19.3, 20.2, 9.67, 28.0, 26.3 and 23.4 cm, respectively. The effect of region was significant only on HaW, PW, HeL, HeW and HL, indicating certain homogeneity among goats of the two regions. Moreover, the inter region variance component ranged from 0 percent (absence of variability) for HS, CW, ChD and ChD to 18.5 percent for HeL, suggesting that the variability of body measurements between Beni Arouss and Rommani regions is very low. The factor analysis revealed four factors, which accounted for 73.5 percent of the total variance. The most discriminant variables between the two populations were HeL, HeW, PW and CW. The Mahalanobis distance between the two populations was 1.197, suggesting that there was genetic exchange between the two populations. The discriminant analysis showed that 80.9 percent of Rommani and 50.0 percent of Beni Arouss individuals were classified into their respective population. Results obtained will help in developing improvement and preservation strategies for the Hamra goat population.

Assessment of genetic diversity of Mithun (Bos frontalis) population in Bhutan using microsatellite DNA markers

Summary Genetic diversity of Mithun population in Bhutan was studied using 14 microsatellite markers. Two sets of two-step polymerase chain reactions were performed with multiplex and individual markers for genotyping 105 hair samples collected from Arong in Samdrupjongkhar (AS, 36) and Wangdigang in Zhemgang (WZ, 69). Fifty-three alleles were detected with average of 3.89 alleles and polymorphism information content of 0.44 ± 0.03 per locus. A low level of genetic variability within population was present with observed heterozygosity at 0.50 ± 0.06 and expected heterozygosity at 0.48 ± 0.06. Analysis of molecular variance attributed 58 percent of total variation to within the individuals. Mean F IS and F IT were −0.056 and 0.005 respectively, indicated low level of population differentiation and limited out-breeding. The normal L-shaped distribution of allelic frequencies without any mode-shift revealed the absence of recent genetic bottleneck in Mithun populations. Therefore to manage inbreeding in the small Mithun population of Bhutan, periodic assessment of inbreeding levels and exchange of animals between farms is recommended to reduce frequency of introduction of animals from India.

Multivariate analyses of morphological traits in indigenous chicken populations of Metekel zone, Northwestern Ethiopia

Summary An exploratory survey to phenotypically characterize indigenous chicken populations was carried out in Metekel zone of Northwestern Ethiopia in April 2013. A total of 69 males and 244 females were sampled to record their qualitative and quantitative traits. Eight quantitative and 16 qualitative variables were measured. Sampling included three districts representing different agroecological zones. Coefficient of variation for quantitative variables ranged from 6.38 to 52.37 percent in male sample populations and 4.59–21.4 percent in females. The chi-square tests for plumage colour of the neck, ear lobe colour and skeletal variant type were highly significant (χ 2 < 0.05). The correct classification percentage from discriminant analysis was 93.73 and 98.41 percent for male and female sample populations, respectively, indicating the homogeneity of the chicken populations within districts. The stepwise discriminant analysis identified five variables for male and three variables for female sample populations, which had the highest discriminating power. Canonical analyses showed that differences in body measurements between indigenous chicken populations were highly significant (P <0.0001). The results obtained from on-farm performance evaluation indicated that the average age at first lay of hens, number of chicks weaned and mean number of eggs laid per bird per year were 5.5 months, 6.5, 50.1, respectively. This information will constitute the basis for further characterization and development of conservation strategies for indigenous chicken populations of Northwestern Ethiopia.

Egg production and certain behavioural characteristics and mortality pattern of indigenous chicken of India

Summary A survey to document the behaviour characteristics and mortality pattern of indigenous chicken of Kerala and a field egg recording study to record egg production characteristics of these birds were conducted. Flight distance and height was 13.29 and 3.97 m, respectively. The territory radius of cocks was 121.15 m. The chick survivability at 4 weeks of age was 64.98 percent. The day-old and 8th week body weights were 28.83 and 347.24 g, respectively. The 20th and 40th week body weight of males were 1,428.42 and 1,936.67 g and that of females were 1,114.04 and 1,445.63 g, respectively. The mortality up to 72 weeks was 69.38 percent and major cause of mortality during chick, grower and layer stage were mongoose (44.63 percent), wolf (24.29 percent) and diseases (52.18 percent) respectively. The fertility was 71.22 percent and hatchability on total and fertile egg set were 62.26 and 87.42 percent, respectively. There were 2.13 clutches in a laying cycle with inter-clutch intervals of 1.11 days. The average clutch size and number of eggs per cycle were 7.27 and 14.32, respectively. The egg number up to 72 weeks on hen-day and hen-housed basis was 116.81 and 85.84, respectively and the eggs were laid in 7.7 cycles. The age at first egg and average age at sexual maturity were 155 and 199.26 days, respectively. The egg weight at 28, 40 and 72 weeks of age was 37.80, 40.74 and 43.31 g, respectively, and egg mass per bird was 4,659.04 g. The broodiness and incubation pause were 26.03 and 121.75 days, respectively.