A systematic immunohistochemical study of the ultimobranchial tubule (UBT) has been carried out in 45 Wistar rats of different ages (0, 5, 10, 15, 20, 25, 30, 60 and 120 days). The existence of calcitonin immunoreactive cells in the UBT wall has been demonstrated in a 5-days old rat. In addition, immunohistochemical studies for thyroglobulin revealed positive staining in follicular cells connected to the UBT and, occasionally, in isolated cells lying within solid clusters from the UBT. These last results together with the continued and repeated existence of numerous mitosis and PAS (+) microfollicles, apparently rising from the UBT, support the hypothesis that the ultimobranchial body (UBB) may contribute partially to the formation of a part of the follicular component. 相似文献
ABSTRACTThe present study was conducted to estimate milk production performance and fit lactation curves for groups of ewes of Local and of Awassi crosses, with a variable blood level, reared under farmer’s environment. The Weigh-Suckle-Weigh method plus hand milking was used to estimate milk yield for ewes. A total of 466 observations from 115 ewes were used. Estimated least-squares adjusted means for the milk production over 120 days were 0.56?kg day?1 (Local), 0.67 (<30% Awassi), 0.86 (30–50% Awassi), and 0.96 (>50% Awassi). Groups with 30–50% Awassi and >50% Awassi ewes produced significantly (p?<?0.05) more milk than Local ewes. Significant differences were observed between <30% Awassi and >50% Awassi crossbred groups. The best crosses (>50% Awassi) produced over 70% more milk than the local ewes which demonstrates the potential that exists in increasing milk production through the initiated crossbreeding programme with sheep in Ethiopia. 相似文献
The aim of this study was to assess the influence of growth on the pharmacokinetics of sodium salicylate (SS) in male turkeys. SS was administered intravenously at a dose of 50 mg/kg. Plasma drug concentrations were assessed by high‐performance liquid chromatography, and pharmacokinetic parameters were calculated by noncompartmental analysis. As the age increased from 6 to 13 weeks (body weight increase from 2.35 to 9.43 kg), median body clearance decreased from 1.34 to 0.87 ml/min/kg. This caused a significant increase in the median mean residence time from 3.42 to 4.44 hr. Elimination phase proved to be biphasic and two elimination half‐lives (T1/2el) were distinguished. Whereas T1/2el1 was found to increase with age by 128%, T1/2el2 represented a later but faster and less age‐dependent phase of elimination (increase by 56% in the respective groups). Volume of distribution decreased with age. These effects may lead to different therapeutic response to SS in turkeys of different age and body weights. 相似文献
1. The effects of changes in technical efficiency on the increase of broiler production are presented for the period 1994–2013 based on the panel data from seven farms located in southern and central Poland. A total of 766 cycles were analysed.
2. The Cobb–Douglas production function was used to assess the changes of output elasticities as well as technical changes in broiler production, for 5-year sub-periods separately.
3. Technical indices of broiler production significantly improved between years 1994–2013: feed conversion ratio decreased from 2.50 kg/kg to 1.78 kg/kg, mortality rate from 8.8% to 4.0% and daily weight gain increased from 37.1 g/d to 58.7 g/d, respectively.
4. Before accession to the EU, there was a substantial increase of fixed capital connected with modernisation of buildings and equipment. In the period 1994–2013, inputs of fixed capital per kilogram of livestock increased by 72% and at the same time the input of labour decreased by 56%.
5. Technical changes in years 1994–1998 contributed to a rapid production increase at a rate of 4.6% annually and only by up to 0.7% annually during 2009–2013. The slowdown of production rate increase after 2009 was partially caused by decreasing the stocking density. 相似文献
Adjustments on planting date and on the time to terminate irrigation may reduce agricultural water use. However, such management practices in regions with extreme weather conditions have the potential to negatively affect yield. A 3‐year (2012–2014) study was conducted on a clay‐loam soil in a cool, semi‐arid environment to (i) determine the response of confection sunflower to planting date and irrigation termination timing and (ii) identify the relative importance of yield components in irrigated confection sunflower across planting dates. Early May planting had considerable negative effects on all studied variables, except on the percentage of large seeds. The highest yield of total and large seeds was obtained from the late May plantings, averaging 3,777 and 3,379 kg/ha, respectively. None of the irrigation strategies affected the measured variables. However, the interaction between planting date and termination of irrigation significantly affected the 1,000‐seed weight. Our study revealed the last week of May as suitable planting period for confection sunflower in the semi‐arid north‐western region of Wyoming, USA, and that irrigation on heavy soils may be terminated as early as at R5.5 stage without a significant yield reduction. The path‐coefficient analysis indicated head diameter and the number of seeds per head as important traits that significantly influence the yield of confection sunflower across planting dates. 相似文献
The allopolyploidization event that created cultivated oilseed rape Brassica napus L, followed by intense breeding, reduced its genetic diversity. Resynthesized (RS) B. napus L. obtained by interspecific hybridization between genotypes of B. rapa L. and B. oleracea L. can be a valuable source for broadening genetic diversity in cultivated oilseed rape. In this study, we determined the extent of DNA polymorphism among natural accessions of oilseed rape, resynthesized B. napus, their parental species and double-low quality semi-RS lines carrying the Rfo gene. Using 10 selected primer combinations, 522 polymorphic AFLP markers were scored in the complete set of 100 Brassica sp. To detect relationships between these genotypes, a cluster analysis was performed using the Jaccard’s distance. Resynthesized allopolyploids clustered directly between their diploid parents. Cultivated accessions of oilseed rape created a compact group away from resynthesized allopolyploids as well as semi-RS lines. The natural oilseed rape group, which consists of 49 cultivars and breeding lines of oilseed rape, is characterized by lower genetic diversity than the group of 33 accessions of resynthesized oilseed rape, and the analysis showed that the double-low quality semi-RS lines represent a specific genetic variation of B. napus. The de novo resynthesized B. napus lines and the semi-RS lines of double-low quality generated from them, provide a significant opportunity for enrichment the gene pool of oilseed rape. 相似文献
Journal of Soils and Sediments - This study analyzes the variability of sediment loads under variant climate change and land use scenarios in a Carpathian catchment with a dam reservoir. The areas... 相似文献
Infrared thermography is a non-invasive technique which allows to distinguish between pregnant and non-pregnant animals. Detecting accurate body surface temperatures can be challenging due to external factors altering thermograph measurements. This study aimed to determine the associations between the ambient temperature, the hair coat features and the temperatures of mares' abdomens. It compared pregnant and non-pregnant mares throughout 11 months. The research was carried out on 40 Konik Polski mares, which were divided into pregnant and non-pregnant groups. The temperature (Tmax, maximal; Taver, average; Tmin, minimal) of the mares' abdomen was evaluated in two regions of interest: the whole area of the lateral surface of the mares' abdomen (Px1) and the flank area of the lateral surface of mares' abdomen (Px2). During the increasing period, the slopes in the linear regression equation did not differ significantly for ambient (Tamb) and surface temperatures in both groups. In the decreasing period, the slopes did not differ significantly for Tamb and Tmax in the non-pregnant group. They also did not differ for Tamb and Taver in Px1 and Tamb and Tmin in Px1 in both pregnant and non-pregnant groups respectively. Other slopes varied significantly (p < .001). There was no evidence of parallel changes in hair coat features and measured temperatures. The flank area appears more suitable for thermal imaging in pregnant mares due to the seasonal fluctuations in hair coat lengths. 相似文献
This study was designed to compare the fatty acid profiles of four types of fat depots from bulls, steers, and heifers. All animals were Polish Holstein-Friesian and Limousin crossbreds fattened semi-intensively—silage at libitum and concentrate in the amount corresponding to 30% of their net energy requirements. The fatty acid profile in intramuscular, intermuscular, and external and internal fat was determined. The intramuscular fat of bulls was most abundant in total PUFAs and n-6 PUFAs, and functional fatty acids C 18:2, C 20:4, and C 22:5 in comparison with steers and heifers. Regardless of sex category, intramuscular and external fat were characterized by higher levels of UFAs and a more desirable MUFA/SFA ratio than the remaining fat types. It should also be noted that external fat was more abundant in CLA than other fat types, and that the highest CLA content was found in bull fat, compared with the remaining sex categories of cattle. 相似文献