No abstract

The introduction of elephants into new groups is necessary for breeding programmes. However, behavioural studies on the reactions of these animals at first encounters are missing. In the present study, female African elephants (Loxodonta africana) living in zoos were observed during unifications with unfamiliar elephants (introduction of two to one females and one to two females; n = 6) and reunifications with related elephants (two mother–daughter-pairs; n = 4) that were separated for 2 and 12 years, respectively. First encounters of the elephants were observed and recorded by scan sampling. The parameters measured were (a) signs of the characteristic Greeting Ceremony, (b) distance to the fence separating the elephants during first contact, and (c) time until trunks touched for the first time. The data were statistically analysed with SPSS. The results showed that related elephants performed a full Greeting Ceremony on reunifications. Unrelated elephants only expressed a minor greeting. During first encounters, related elephants predominantly showed affiliative behaviour (p = 0.001), whilst unrelated elephants expressed more agonistic behaviour (p = 0.001). The distance to the fence was significantly smaller for related elephants than for unrelated elephants (p = 0.038). first contact of trunks occurred on average after 3.00 s. in related elephants and 1026.25 s. in unrelated elephants. These findings indicate that related elephants recognise their kin after up to 12 years of separation, meet them with a full Greeting Ceremony during reunification, and seek contact to the related elephant, while unrelated elephants are hesitant during unifications with unfamiliar elephants and express more agonistic behaviour. The results testify that zoo elephants show the same species-specific social behaviour as their conspecifics in the wild. It also confirms the cognitive abilities of elephants and the significance of matrilines for breeding programmes.

Food consumption recording is a social need because the consumption is an indicator of the nutrition status that means the health status, of the population, and an economic factor. Food consumption trends in the nineties are characterized by a steep fall of most kinds of foods, mainly from animal sources. It is not necessary to adjust this fact with respect to recent data of the time series. Four commodities show a positive increase. The trend of food consumption is bound up with more slowly increasing incomes of the population than was the increase in food prices after their liberalization. The consequences of consumption trends do not imply any deterioration of nutrition status because nutrition requirements have been met except calcium and vitamin A supply due to a decrease in milk consumption, and except vitamin C, still a deficient element although its supply has substantially increased. A systematic attention should be focused on the population nutrition through nutrition and food policies.

The article deals with cyclical abrasive wear of the surface of forming tools. At this stage the research focused on the genesis of stress in the contact between a deformed material and a tool in the cold bulk forming process. The experiments were conducted in the simple configuration of the upsetting test. The article presents the results of abrasive wear by a combination of materials of examined samples and upsetting plates. The abrasive wear in the used material specimens was analysed comparatively in the form of the wear factor by the finite element method. Two intersecting phenomenological fields represent the output for the examined material combinations. Firstly, it is a formulation of the dependencies of the maximum depth increase of the surface wear. The argument is the number of exposure cycles. At the same time, the topology of degradations and the resulting roughness in the space of the exposed surface were examined.

No abstract

The paper deals with stress of forming dies in complex conditions of concrete processes during their service life. Possibilities of assessment and prediction of tool service life based on comparative analysis of dynamic fatigue and abrasive wear are presented. Classical solution of dynamic fatigue is complemented by analysis of the situation of cyclic contact of rotating instruments. In this case super-position of cyclic pressure effect dominates, as well as abrasion on the surface of the functional surfaces of the rotating forming tool. Specific in this case is the different speed in the contact line and also the dynamics of development of size, shape and localisation of the surface exposed to wear by cyclic compressive stress. The solution is demonstrated on examples of different forms of wear of forging and rolling tools. The results of a comprehensive predictive analysis can be applied at designing of technological chains of forming operations.

Giraffe numbers have plummeted over the last 30 years by 30–40%. Thus, their conservation status has been raised from least concern to vulnerable. Efforts to manage in situ and ex situ populations are increasing. Assisted reproduction techniques (ART) such as sperm cryopreservation could help preserve the genetic diversity of giraffe subspecies and, when used for artificial inseminations, enhance genetic exchange between isolated populations. However, to date, the post-thaw motility of recovered sperm has been low and inconsistent. In this study, epididymal sperm collected from the testes of giraffes (n = 7) was frozen in three different extenders, namely, BotuCrio, Steridyl, and test egg yolk (TEY), each supplemented with one of two different cryoprotectants (5% glycerol or a mix of 1% glycerol and 4% methylformamide) and frozen over liquid nitrogen vapor. Across all three extenders, sperm showed significantly better post-thaw results when frozen with a mix of glycerol and methylformamide compared with glycerol alone. Sperm frozen with TEY and a mix of glycerol and methylformamide achieved superior post-thaw total and progressive sperm motility of 57 ± 3% and 45 ± 3%, respectively. These results show the benefit of using alternative cryoprotectants for freezing giraffe spermatozoa and could aid in the application of ARTs for giraffe subspecies or the closely related endangered Okapi.

No abstract