Refine search
Results 1-10 of 51
Non-genetic factors affecting early growth traits and survival in Horro sheep
2002
Abegaz, Solomon | Duguma, G. | Gelmesa, U. | Terefe, F. | Negussie, E. | Rege, J.E.O.
Factors affecting the early growth and survival of indigenous Ethiopian Horro sheep were identified and the influence of each was assessed, based on data collected from 1978 97 from 4031 lambs at Bako Research Centre, Ethiopia. Year of birth, sex, type of birth or rearing, and parity had significant (P < 0.01) effects on birth weight (BWT), weaning weight (WWT), and six month weight (6MWT). With the exception of parity, the same factors affected yearling weight (YWT). Male lambs were heavier by 0.14, 1.1, 1.9, and 4.2 kg than females in BWT, WWT, 6MWT, and YWT. Single born lambs were heavier by about 0.5 kg than multiple born lambs at birth. Lambs born from primiparous ewes were lighter by 0.2 0.3 kg than lambs born from multiparous ewes at birth. With the exception of effect of type of birth and ewe age on survival to 3 and 7 days of age, respectively, year of birth, ewe (dam) age, type of birth, and BWT had significant (P < 0.01) effect on survival from three days to one year of age. The survival of multiple-born lambs was 0.8, 3.7, 8.3, 12.2, and 12.496 lower than single-born lambs at the age of 3, 30, 90, 180, and 365 days, respectively. Lambs born from primiparous ewes had lower survival rates compared to those born from multiparous ewes. Survival was very low in lambs with low BWT and improved with increase in BWT. In general, there are indications that there exists a critical BWT (about 2.6 kg) below which the survival of lambs declines drastically.
Show more [+] Less [-]Studies on the growth performance of native chicken ecotypes and RIR chicken under improved management system in northwest Ethiopia
2006
Hassen, H. | Neser, F.W.C. | Dessie, Tadelle | Kock, A. de | Marle-Koster, E. van
A study was conducted to evaluate the growth performance of native and RIR chickens under intensive management condition for 22 weeks using a standard commercial ration. Seven native chicken populations were collected from representative administrative zones in northwest Ethiopia. The experimental layout was a Completely Randomized Design (CRD) with three replications. Data on feed consumption, body weight and related parameters were collected up to the age of 22 weeks. The mean total feed intake for the seven native chicken ecotypes and RIR chicken lines at the end of their growth phase were 13.80, 15.16, 13.44, 13.25, 13.81, 13.36, 14.11 and 12.83 kg for the native chicken types named as Tilili, Gellilia, Debre-Ellias, Mello-Hamusit, Gassay, Guangua, Mecha and RIR, respectively. There was no significant difference in feed consumption among the tested chicken ecotypes. However, a significant (p<0.05) difference was observed in average body weight and body weight gain between the different lines. The average body weights for Tilili , Gellilia, Debre-Ellias, Mello-Hamusit, Gassay, Guangua, Mecha and RIR were 1191, 1186, 1054, 1222, 1038, 1249, 1257 and 1394 g respectively. The lowest and highest mean mature body weight at the age of 22 weeks were 1038 g for Gassay and 1257g for Mecha native chicken lines, respectively. Besides, the average mature body weight for Tilili, Gellilia, Debre-Ellias, Mello-Hamusit, Gassay, Guangua, Mecha and RIR was 1191, 1186, 1054, 1222, 1038, 1249, 1257 and 1394 g and their mean daily body weight growth rates were 7.6, 7.5, 6.7, 7.8, 6.6, 7.9, 8.0 and 8.8 g per bird, respectively. The native chicken lines named as Mello-Hamusit, Guangua and Mecha were the fastest growers among the native chicken lines. Mortality from hatching to end of the growth period i.e. at maturity was higher for all the native and RIR chickens used under intensive management condition.
Show more [+] Less [-]The feed values of indigenous multipurpose trees for sheep in Ethiopia: The case of Vernonia amygdalina, Buddleja polystachya and Maesa lanceolata
2008
Haile, Aynalem | Tolemariam, T.
The feed resources base, the feeding systems and feed values of three indigenous trees Girawa, Anfare and Kelewa (Local (Amharic), Ethiopian names ) were studied for sheep in sub humid, mid altitude area of south western Ethiopia. The study involved a survey of the feed resources base and assessment of the feeding systems, chemical analysis and in vitro dry matter digestibility. In addition, Girawa was selected to study its effect on growth performances using 32 lambs. The levels of Girawa used for the growth performance study in groups I, II, III and IV, respectively were 100 g/d, 200 g/d, 300 g/d and 400 g/d. The main feed resources for sheep in Jimma area were found to be natural pasture, crop residues, crop aftermaths and indigenous multipurpose trees. Grazing on natural pasture constituted the main feeding system. The indigenous trees were cut and fed occasionally. The levels of CP ranged from 186.2 to 244.4 g/kg DM with minimum level in Anfare. Higher values were recorded for Girawa. Organic matter content was higher for Anfare (924.3 g/kg DM) and lower for Girawa (877.9 g/kg DM). In vitro dry matter digestibility values were 0.448, 0.422 and 0.458 for Girawa, Anfare and Kelewa, respectively. Supplementation of Girawa had an effect (p<0.01) on live weight gains of lambs. Lambs that were offered 400 g/d of Girawa had a higher daily live weight gain (95.1 g/d) compared to those supplemented with 200 (43.3 g/d) and 300 g/d (50.5 g/d) of Girawa as well as the control group (34.0 g/d). Weight gains were not different between the control group and those supplemented with 200 and 300 g/d of Girawa. It was concluded that these feed resources represent a great potential for sheep production in areas where the resources are available. It is also suggested that more studies are needed on higher level of Girawa than the present study on animal performances along with its anti-nutritional effects.
Show more [+] Less [-]Effects of irrigation and woodchip mulch on growth and habit of sour cherries
2009
Feldmane, D., Latvia Univ. of Agriculture, Jelgava (Latvia)
Sour cherries become more popular due to their food value. Therefore sour cherries could be a profitable crop for fruit growers in Latvia. Information about sour cherry response to soil moisture adjustment is needed, because based on previous studies it is not possible to predict the influence of irrigation and mulch on sour cherry growing. The trial was carried out at the Latvia State Institute of Fruit Growing in 2007 to determine the effect of soil moisture adjustment on the growth of different sour cherry cultivars. Woodchip mulch and drip irrigation were used as main factors, cultivars 'Bulatnikovskaya', 'Desertnaya Morozovoi', 'Latvijas Zemais', 'Orlica', 'Shokoladnica', 'Tamaris', 'Zentenes' were used as a secondary factor. Vegetative growth, branching angles of lateral shoots, proportions of pruned shoots, spurs and twigs were determined to characterize the response of cultivars to mulching and irrigation. In general use of drip irrigation increased vegetative growth of sour cherries, but the use of woodchip mulch decreased this growth. Branching angles were wider in variant with woodchip mulch. Cultivar 'Zentenes' most positively responded to use of woodchip mulch and drip irrigation.
Show more [+] Less [-]Inhibition of microbial growth of a salad with meat in mayonnaise by different packaging technologies
2009
Levkane, V., Latvia Univ. of Agriculture, Jelgava (Latvia) | Muizniece-Brasava, S., Latvia Univ. of Agriculture, Jelgava (Latvia)
The objective of the research was the shelf life extension of a salad with meat in mayonnaise. The microbial stability of the salad with meat in mayonnaise packaged under vacuum, in modified atmosphere, and using 'Sous vide' technology was examined and compared with conventionally packaged (in ambient air) salad. The salads were packaged in polyamide/polyethylene pouches with barrier properties as well as in pouches made from biodegradable plasticized poly-β-hydroxybutyrate or polylactic acid film. Control samples without preservatives were packed in traditional polypropylene containers covered with non-hermetic lids. PURASA L Powder Opti Form (sodium lactate) in the amount 5 g kgE-1, 10 g kgE-1, and 15 g kgE-1, and ethyl alcohol in the amount of 2 ml were used as single preservatives for separate samples. The studies of the samples were carried out after 1, 3, 7, 10, 15, 18, 25, 29, 42, and 52 storage days at the temperature of +4+-0.5 deg C. Experimentally the quality of the salad with meat in mayonnaise was characterized by measuring the total plate count of microorganisms. The obtained results indicate that different packaging technologies and addition of preservatives show significantly different influence on the microbial growth in different samples. 'Sous vide' packaging technology was effective for the shelf life extending and guarantee of safety of the salads with meat in mayonnaise.
Show more [+] Less [-]Geographical differences in growth and quality characters of Scots pine Latvian populations
2009
Neimane, U., Latvia Univ. of Agriculture, Jelgava (Latvia)
In the study the growth and stem quality characters of geographically different Latvian Scots pine (Pinus sylvestris L.) populations were evaluated. In various regions of Latvia proportionally to the distribution of Scots pine 21 sample plot was established in 85 to 95 years old pure stands in forest type Myrtillosa growing conditions. In every sample plot 100 trees were evaluated estimating height of the tree, diameter at breast height, stem volume, length and quality of the branch-free stem section, relative branch thickness, branch angle and stem straightness. Pine populations were compared in different seed zones (Western and Eastern), as well as in various regions (Western, Central, South-eastern, North-eastern). In order to describe the geographical differences of populations with help of growth features, tree height was chosen because the relation between height and stem quality features is positive. The populations of the Eastern seed zone substantially overcome the populations of the Western seed zone both in terms of growth features, as well as in stem quality. Substantial are also differences between populations growing in various regions in terms of average height, length and quality of branch-free stem section, relative branch thickness and branch angle, but not stem straightness. Western populations present the lowest growth feature values and stem quality. The height and stem quality features of the North-eastern populations considerably exceeded the features of other regions' populations.
Show more [+] Less [-]Survival, growth and reproductive performance in F1 crossbred cattle produced and managed on station in the Gambia
2004
Diack, A. | Sanyang, F.B | Corr, N.
In a trial whereby a large number of cows were needed to calve at approximately the same time, opportunity was taken to establish a crossbred cow population at the International Trypanotolerance (ITC). A slight improvement in the traditional husbandry system revealed a great productivity potential of these crossbreds. Their survival rate to one year (i.e., 90.0%for the Jersey X N’Dama (J X N) and 71.2% for the Friesian X N’Dama was proved satisfactory in the local environment, though conclusions are that more attention is needed for rearing Friesian type F1 calves in the tropical environment. With an overall mean birth weight of 17.7±4.1 kg and an overall mean daily weight gain (DWG) of 0.220±0.104 kg they attained an average weight of 100.6±29.9 kg at one year. Their relatively retarded growth recommended a better management. Puberty was attained at 478.2±13.9 days, age at first calving 970.5±94.1 days and the overall mean calving interval and open period were 400±82.5 and 117±83.2 days, respectively.
Show more [+] Less [-]Temporal structure of middle-aged Norway spruce stands of low growth potential on drained sites
2010
Libiete-Zalite, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Zalitis, T., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Large proportion of 30-50 years old spruce stands originated from overstocked plantations can be characterized by low growth potential and present serious problem to forest managers. Although according to legislation unproductive spruce stands can now be clearcut, possible alternative solution allowing a forest owner to remove only trees with the worst growth potential would be also welcome. To be able to recommend any silvicultural measures, information on the inner structural development of the stands is necessary. The aim of this study was to analyze temporal structure of several spruce stands that have originated from overstocked plantations and now belong to the 2nd (increased risk stands) or 3rd (unpromising stands) growth potential groups. Data for the study from seven sample plots located in Forest Research Station ''Kalsnava'' and thinned with different intensity were used. Tree diameter distribution, volume accumulation patterns and tree mortality were analyzed. Correlation between tree diameter and tree diameter difference in the observation period from 2000 to 2006 was weaker than in the observation period from 2006 to 2009, indicating further decline of growth potential. In most cases the major part of the volume was accumulated in the middle of the diameter class distribution. For most of the trees one or both sawlogs were of good or average quality. In order to develop optimal and profitable stand management model, the effect of different thinning methods in spruce stands of low growth potential should be studied in the future.
Show more [+] Less [-]Impact of amelioration system renovation on the growth of mature forest stands
2010
Zalitis, T., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Libiete-Zalite, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Both forestry theory and practice have proved that amelioration favours the growth of forest stands significantly. The growing stock increases even 10 times, if the amelioration system is well-functioning. Joint Stock Company Latvia State Forests that is managing half of forests in Latvia has started renovation of old amelioration systems aiming to improve the productivity of state owned forests in Latvia. In order to evaluate the impact of the renovation of the old amelioration systems, a tree ring width in 7 pine stands, 5 spruce stands and 3 birch stands was analysed. This study shows that the renovation itself has not affected the productivity of mature pine, spruce and birch significantly 3-4 years after the renovation. Authors have come to a conclusion that the reason for that could be too short observation period or particularities of a stand structure and age.
Show more [+] Less [-]Growth of Fagus sylvatica in young mixed stand: case study in central Latvia
2016
Purina, L., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Adamovics, Andis, Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Katrevics, J., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Katrevica, Z., Latvian State Forest Research Inst. Silava, Salaspils (Latvia) | Dzerina, B., Latvian State Forest Research Inst. Silava, Salaspils (Latvia)
Climatic changes are shifting the potential tree distribution limits of many tree species northwards. One of such species is Fagus sylvatica, currently represented in Latvia only by a few stands. In order to increase knowledge on its potential use in the forest management, the aim of our study was to characterize the growth of beech in a young stand in the central part of Latvia. The stand of beech and spruce, mixed in rows with an initial spacing of 2.5 x 2.5 m in Oxalidosa forest type was assessed. Survival of European beech in clear cutting was similar to that observed for the native Norway spruce (73% and 79%, respectively), but both height and diameter were notably and significantly superior for wildlings at the mean age of 15 ± 2 years, reaching on average 7.4 ± 0.30 m and 8.9 ± 0.69 cm, respectively. Increasing ring width with increasing tree age for both tree species was observed until the last four years, when large and increasing superiority of beech over spruce, coinciding with reduction of ring width of spruce, was noted. It was most likely caused by intensified competition due to very wide crowns formed by young beech trees in the plantation with wide spacing: average crown radius reached 2.4 ± 0.16 m, for few trees exceeding even 4 m.
Show more [+] Less [-]