24 research outputs found
ВЛИЯНИЕ НА ПОЛОВОТО СЪОТНОШЕНИЕ ВЪРХУ ОПЛОДЕНОСТТА НА ЯЙЦАТА ПРИ МУСКУСНА ПАТИЦА (CAIRINA MOSHCATA)
No full textStudy was carried out for establishing the optimal sex ratio in Muscovy duck breeding. Four variants of the ratio of the male to the female individuals were tested: 1:5(I), 1:6(II), 1:7(III) and 1:8(IV). In the frames of each sex ratio (variant), two subgroups (sub-variants) were formed with the aim of establishing the effect of the hierarchy relations among the drakes on egg fertility: with one male in a group (A) and with more than one male in a group (B). The highest egg fertility – 97.09 % was achieved at 1:5 sex ratio (with more than one drake in a group) and the lowest – 93.41 % at 1:8 sex ratio (with a single male in a group). Signifi cant decrease in egg fertility was registered when increasing the sex ratio to 1:8, that effect being displayed more weakly at more than one male in the group. When increasing the ratio, the presence of more than one drake in the family group exerted a positive infl uence on egg fertility, due to the preference of the males to certain females and
the distribution of the rest of the females among the drakes placed in the hierarchy below the “alpha”, depending on their grade in the hierarchy order. The most appropriate sex ratio for Muscovy duck species was 1:5, and, when there was shortage of the male reproduction material, 1:6 ratio was also acceptable, especially if more than one drakes were placed in the family group (effect of supporting the alpha)
ПРОУЧВАНЕ ВЪРХУ ТЕМПЕРАТУРНИЯ РЕЖИМ ПРИ ИНКУБИРАНЕ НА ЯЙЦА ОТ МУСКУСНА ПАТИЦА (CAIRINA MOSCHATA) I. ПРОУЧВАНЕ ВЪРХУ ТЕМПЕРАТУРНИЯ РЕЖИМ ПРИ ЕСТЕСТВЕНО ЛЮПЕНЕ НА ЯЙЦА ОТ МУСКУСНА ПАТИЦА
No full textStudy was carried out on the temperature regime on the surface of naturally hatched Muscovy duck eggs with the aim of its specifying during artificial incubation. Egg fertility and hatchability during the whole period of study were reported in the experimental hatches.
Depending on the period of the embryo development, on the ambient temperature and the egg position in the nest, the
surface temperature of the naturally hatched Muscovy duck eggs varied between 35.78 and 38.87о С. The temperature increase of the upper egg surface after the 20th – 23st day of the embryonic development to 37.92 - 38.87о С was due to the use of yolk fats by the embryos leading to the release of more heat.
As a result of the observations on the temperature regime of the surface of naturally hatched Muscovy duck eggs, we recommend that during artificial hatching of eggs from the same waterfowl species the following temperature should be maintained:
– until closing of the allantois - 37.6 – 37.8 о С.
– from closing of the allantois until the transfer into the hatchery - 37.2 – 37.5 оС.
– in the hatchery - 36.7 – 37.0 оС.
– water cooling of eggs by it twofold per day sprying with distilled water at 18–20°С, since 20th, instead of 8th or 16th day of embryonary development, or accomplish it in hatchery only
ПРОУЧВАНЕ ВЪРХУ ЯЙЧНАТА ПРОДУКТИВНОСТ ПРИ МУСКУСНА ПАТИЦА (CAIRINA MOSCHATA) В ЗАВИСИМОСТ ОТ НАЧИНА НА ОТГЛЕЖДАНЕ
No full textStudy was conducted on egg laying productivity and egg fertility of Muscovy duck in conventional and biological breeding of the fowls. The higher biological degree in the breeding method has lead to signifi cantly higher values of all the studied characteristics: 4-week prolongation of the laying season, higher values in the laying peaks, greater egg weight (85.32 versus 78.36 g ***) and egg fertility (97.81 versus 96.18% *). Summer spells of hot weather and the
high laying capacity in the peak did not exert a negative effect on the egg weight and fertility in biological breeding of the layers
EFFECT OF THE SEX RATIO ON THE EGG FERTILITY OF MUSCOVY DUCK (CAIRINA MOSHCATA)
No full textStudy was carried out for establishing the optimal sex ratio in Muscovy duck breeding. Four variants of the ratio of the male to the female individuals were tested: 1:5(I), 1:6(II), 1:7(III) and 1:8(IV). In the frames of each sex ratio (variant), two subgroups (sub-variants) were formed with the aim of establishing the effect of the hierarchy relations among the drakes on egg fertility: with one male in a group (A) and with more than one male in a group (B). The highest egg fertility – 97.09 % was achieved at 1:5 sex ratio (with more than one drake in a group) and the lowest – 93.41 % at 1:8 sex ratio (with a single male in a group). Signifi cant decrease in egg fertility was registered when increasing the sex ratio to 1:8, that effect being displayed more weakly at more than one male in the group. When increasing the ratio, the presence of more than one drake in the family group exerted a positive infl uence on egg fertility, due to the preference of the males to certain females and the distribution of the rest of the females among the drakes placed in the hierarchy below the “alpha”, depending on their grade in the hierarchy order. The most appropriate sex ratio for Muscovy duck species was 1:5, and, when there was shortage of the male reproduction material, 1:6 ratio was also acceptable, especially if more than one drakes were placed in the family group (effect of supporting the alpha)
STUDY ON THE TEMPERATURE REGIME IN INCUBATION OF MUSCOVY DUCK EGGS I. STUDY ON TEMPERATURE REGIME IN NATURAL HATCHED MUSCOVY DUCK EGGS
No full textStudy was carried out on the temperature regime on the surface of naturally hatched Muscovy duck eggs with the aim of its specifying during artificial incubation. Egg fertility and hatchability during the whole period of study were reported in the experimental hatches. Depending on the period of the embryo development, on the ambient temperature and the egg position in the nest, the surface temperature of the naturally hatched Muscovy duck eggs varied between 35.78 and 38.87о С. The temperature increase of the upper egg surface after the 20th – 23st day of the embryonic development to 37.92 - 38.87о С was due to the use of yolk fats by the embryos leading to the release of more heat. As a result of the observations on the temperature regime of the surface of naturally hatched Muscovy duck eggs, we recommend that during artificial hatching of eggs from the same waterfowl species the following temperature should be maintained: – until closing of the allantois - 37.6 – 37.8 о С. – from closing of the allantois until the transfer into the hatchery - 37.2 – 37.5 оС. – in the hatchery - 36.7 – 37.0 оС. – water cooling of eggs by it twofold per day sprying with distilled water at 18–20°С, since 20th, instead of 8th or 16th day of embryonary development, or accomplish it in hatchery only
STUDY ON EGG LAYING CHARACTERISTICS OF MUSCOVY DUCK (CAIRINA MOSHCATA) DEPENDING ON THE BREEDING METHOD
No full textStudy was conducted on egg laying productivity and egg fertility of Muscovy duck in conventional and biological breeding of the fowls. The higher biological degree in the breeding method has lead to signifi cantly higher values of all the studied characteristics: 4-week prolongation of the laying season, higher values in the laying peaks, greater egg weight (85.32 versus 78.36 g ***) and egg fertility (97.81 versus 96.18% *). Summer spells of hot weather and the high laying capacity in the peak did not exert a negative effect on the egg weight and fertility in biological breeding of the layers
ВЛИЯНИЕ НА ПРОБИОТИК ЛАКТИНА® ВЪРХУ НОСЛИВОСТТА И ОПЛОДЕНОСТТА И ЛЮПИМОСТТА НА ЯЙЦА ОТ МУСКУСНА ПАТИЦА (CAIRINA MOSHCATA)
No full textThe effect of Laktina® probiotic on some major characteristics of the reproduction capacity of Muscovy duck (White variety) has been studied. The experiment was carried out with 96 ducks in their fi rst reproduction season, distributed into an experimental and a control group of equal numbers. The combined forage for feeding the experimental group contained 500 g/t of the tested probiotic. The following characteristics were studied: egg production, egg weight,
fertility and viability (hatchability of fertile eggs). It was established that the average egg production (93.91 versus 67.88 eggs per duck) and the egg-laying intensity for the period (45.92 versus 34.63 %) were in favour of the group receiving probiotic, the advantage being statistically signifi cant (p< 0.001) and sustainable throughout the season. The advantage of 2.33 g in the egg weight (p< 0.001) of the control group was explained by the signifi cantly increased laying capacity of the ducks from the experimental group.
No effect of Lactina probiotic was established on egg fertility and viability
EXPERIMENTAL INFLUENCE OF LAKTINA® PROBIOTIC ON EGG LAYING CHARACTERISTICS, FERTILITY AND VIABILITY IN MUSCOVY DUCK (CAIRINA MOSHCATA)
No full textThe effect of Laktina® probiotic on some major characteristics of the reproduction capacity of Muscovy duck (White variety) has been studied. The experiment was carried out with 96 ducks in their fi rst reproduction season, distributed into an experimental and a control group of equal numbers. The combined forage for feeding the experimental group contained 500 g/t of the tested probiotic. The following characteristics were studied: egg production, egg weight, fertility and viability (hatchability of fertile eggs). It was established that the average egg production (93.91 versus 67.88 eggs per duck) and the egg-laying intensity for the period (45.92 versus 34.63 %) were in favour of the group receiving probiotic, the advantage being statistically signifi cant (p< 0.001) and sustainable throughout the season. The advantage of 2.33 g in the egg weight (p< 0.001) of the control group was explained by the signifi cantly increased laying capacity of the ducks from the experimental group. No effect of Lactina probiotic was established on egg fertility and viability
Preliminary study of river- and beach processes in the Matina region of Costa Rica
No full textThe starting point for this project are the severe erosion problems at the Pacuare Nature Reserve, situated on the Caribbean coast of Costa Rica. The Reserve’s installations are situated next to a lagoon which is separated from the open sea by a barrier beach. The lagoon is connected on the landward side to local river? and channel system. During periods of high rainfall, the lagoon is susceptible to break through to the open sea. After such breaches, high flow velocities and waves have caused significant land?loss and subsequently endangered the continued existence of the buildings at the Reserve. Since 1989, recorded breaches occurred in 1994, 2005 and 2009. It is believed that erosion of land is mainly caused by breaching events rather than continued coastal erosion by waves or currents. The breaching events may be caused by the increasing channelisation of river and drainage stretches and increasing water discharges by cultivated areas in former natural flood?plains. These interventions may be beneficial for some populated areas who are protected by channelised section and for the economy in certain regions as formerly unused land becomes productive (enabling banana plantations). However, the interventions increase the volume of water to be discharged in a confined space which reduces the capacity to discharge water safely towards open sea. The objective is to present recommendations for safely discharging water during extreme events towards the open sea, in which the ‘small scale’ breakthrough problem forms the criterion for damage for the reserve. The project consists of two areas of interest: river? and beach processes. The river processes were analysed and solutions were sought to safely discharge water using a computer model which models the real life processes. These solutions focus on the macro scale problem, and interfere in the water system as a whole. Analyzing the beach processes involved identifying the key processes in the stretch of coast between the Río Matina and Río Pacuare and modelling these processes in a computer model. Possible small scale solutions were then tested in the computer models and assessed on their effectiveness. These small scale solutions have to be interpreted as interventions the Reserve staff can implement themselves to help prevent the continued erosion during extreme events.Hydraulic EngineeringCivil Engineering and Geoscience
The Changing Challenge: From Double Bind to Double Burden
No full textHas fear of success been overcome by our focus on individual achievement, or is today\u27s working woman caught in an ever more exhausting circle of high expectations and guilt? The author of this article notes that professional accomplishment and femininity were once viewed as mutually exclusive, creating a double bind for women who wanted both, driving some to avoid too much success. But today, the economic interdependence of men and women is a reality, requiring that we move beyond the debate of the proper role of women and look at the real issues: burden sharing, support systems, and stresses on women and their families. The conclusion of this examination of why many working women feel both overextended and undervalued is that women will succeed and society benefit only if we all join in helping to find ways to resolve these pressures
