Animal Breeding and Genetics

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/64

Browse

Filters

2020 - 20252

Settings

Has files: YesSubject: search.filters.subject.Ethiopia

Search Results

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    ESTIMATION OF GENETIC AND PHENOTYPIC PARAMETERS FOR MILK PRODUCTION AND REPRODUCTION TRAITS IN A DEVELOPING SYNTHETIC DAIRY CATTLE BREED AT HOLETA AGRICULTURAL RESEARCH CENTER, ETHIOPIA
    (Hawassa University College of Agriculture, 2025) ASAMENEW AYALEW
    This study was carried out to estimate genetic and phenotypic parameters for milk production and reproduction traits of synthetic dairy cattle breed development program being implemented at Holeta research center dairy farm. Data collected from 1995 through 2024 on lactation milk yield, lactation length ,daily milk yield, age at first service, age at first calving, and calving interval from experiments targeted to develop synthetic breed at Holeta Agricultural Research Center dairy herd were used for this study. The GLM procedures of SAS software were used to estimate the effect of fixed effects such as year, season and parity while regression analysis was performed to estimate crossbreeding parameters (additive, heterosis and recombination effects). Genetic components including variance covariance estimates were analyzed using WOMBAT software. A univariate mixed model for genetic Parameters and Multiple Regression Model for crossbreeding parameters was used for data analysis. The performance of dairy cattle affected by genetic and non-genetic factors. The result of fixed effects (year and genetic group) analysis showed that a significant (p<0.0001) differences in all productive and reproductive traits. Correspondingly, productive traits (LMY and DMY) and reproductive (CI) traits were also significantly (p<0.0001) influenced by parity. The traits, lactation milk yield, were sensitive to seasonal variation. The overall least squares means for lactation milk yield (LMY), daily milk yield (DMY), lactation length (LL), age at first service (AFS), age at first calving (AFC) and, calving interval(CI)were 2140.61 ± 32.92kg, 6.89 ± 0.07kg, 316.54 ± 3.31days, 33.56 ± 0.63months, 42.78 ± 0.63months and, 469.01 ± 7.03days, respectively. Additive genetic effects were much larger than for the non-significant negative value of heterosis effect of lactation milk yield (3728 ± 139.39 kg of additive and -81.65 ± 97.98 kg of heterosis).The cross breeds were -21.51± 29.19 days, -2.29 ± 3.12 months, and -2.23 ± 3.12 months, reduced for CI, AFS and, AFC due to the additive effect of Friesian gene. Estimation of heritability for productive traits (LMY, DMY and LL) were 0.180 ± 1.00, 0.235 ± 0.053 and 0.219 ± 0.077, respectively and reproductive traits (AFS, AFC, and CI) 0.0798 ±0.034, 0.080 ±0.033and 0.180 ± 0.042, in respective order. The current result indicated that repeatability values of productive traits 0.589 ± 1.00 for LMY, 0.491± 0.227 for DMY, 0.735± 0.151 for LL, and0.23±0.01 for CI. The current study indicated that the direct genetic correlation between productive traits were positive and ranged from very weak (0.141 ± 0.073) to very strong (0.854 ± 0.304) genetic correlations. From the current study high correlation was observed in between LMY and LL (0.854 ± 0.304). The current study indicated that positive genetic correlation ranged from very weak to weak genetic correlation among reproductive traits. AFS-AFC (0.228 ± 0.172), AFS-CI (0.181 ± 0.194), AFC-CI (0.063 ± 0.02).The present study indicated that the genetic correlation among productive and reproductive traits was closely related with each other in some traits. Strong genetic correlation looked between CI-LL (0.785 ± 0.074), moderate genetic correlation between CI-LMY and AFC-LL (0.428 ± 0.098, and 0.40 ± 0.107), respectively. Thus, based on the study's findings, it was feasible to draw the conclusion that proper parental line selection and crossing should be used to create next-generation calves and improve the farm's overall management system.
  • No Thumbnail Available
    Item
    SOME PHYISICAL AND CHEMICAL PROPERTIES OF CASHMERE TYPE FIBERS FROM LONG HAIRED ARSI BALE GOATS
    (Hawassa University College of Agriculture, 2020) BALI TESFAYE SORA
    A study was carried out to access the fleece quality parameters of long haired Arsi Bale goats which are reared at Dinsho and Agarfa District of Oromia regional state. The long haired Arsi Bale goats are raised in the cold areas of Bale zone and have very long hairs and warm undercoat. Earlier studies have indicated that the goats are raised primarily for their skin and pelt which are used as saddle cover and also for covering of furniture’s in the home. This study was carried out to access the physical and chemical quality of the fleece obtained from healthy bucks and does reared in the selected kebeles of Dinsho and Agarfa District. Proportional sampling method was used to identify the bucks and does. Based on the same 21 bucks from Dinsho district and 17 from Agarfa district and 29 does from Dinsho district and 33 from Agarfa district were selected. The age of the bucks was determined by their dentition and only adult (>1 year old) goats were selected for the fleece. The fleeces were combed from the neck region of the healthy goats and then they were packed in plastic bags before being transported to the laboratory at School of Animal and Range Science laboratory. The fleece were studied for staple length, numbers of crimps/inch, numbers of hairy, hetero and fine fibers, average diameter of the hetero, hairy and fine fibers (in micron). The chemical properties of the fleece included the percentages of ash, wax, scouring yield and burr. The numbers of fleece and their diameter was accessed using a digital microscope at 40X magnification. The data were analyzed for the effects of location and sex on the fleece quality parameters. The findings for the bucks indicated that there were differences (P<0.05) only in crimp, numbers of pure fibers and scouring yield of the bucks reared in the two locations. While among the does there were differences P<0.05 in staple length, crimp, fiber diameters (hairy, hetero and pure), in percentages of ash, scouring yield and wax of the bucks reared in the two Districts. The study also shows that there was a wide variation in the numbers of pure, hetero and hairy fleece while, differences in the fiber diameter were minimum. The study pertaining to the effects of sex further indicated that there were differences in the fiber wax parameter among the bucks and does raised at Dinsho. In Agarfa district there were differences (P<0.05) in staple length, numbers of hairy fibers, hetero and pure fibers, hetero and pure fiber diameters. The within sex differences due to location can be due to the adaptability of the goats to the locations and also due to crossings of the bucks/does with the short haired Arsi Bale goats. The differences between the sexes within locations can be ascribed due to sexual dimporphism and also the traditional breeding objectives which differ across the sexes. There was a possibility of selection within the genotypes for the parameters studied and thereafter further improving the same.