Human in Vitro Fertilization: Lessons from Unrealized Fears and Unexpected Benets

Za tři desetiletí se technika in vitro oplození proměnila z oboru, v který věřil jen málokdo, na techniku, která je pevnou součástí moderní medicíny. Obavy, které s ní byly spojovány, se nenaplnily. Naopak, in vitro oplození našlo uplatnění i tam, kde to nikdo nepředpokládal. V kombinaci s předimplantační genetickou diagnostikou se využívá jako prevence dědičných onemocnění. Potřeba oplození in vitro se ukázala i v zemích třetího světa, které se potýkají s důsledky populační exploze.V současnosti se rozvíjejí nové biotechnologie, které narážejí na odpor veřejnosti. Historie se opakuje. Jsou zdůrazňovány především jejich možná i ryze hypotetická rizika a mnohé jejich budoucí přínosy nejsou a za současného stavu poznání ani nemohou být předvídány.Rozvoj in vitro oplození nabízí lekci pro hodnocení nastupujících biotechnologií. Jejich výrazné omezení nebo dokonce zákaz by zjevně znamenaly pro budoucnost lidstva závažná omezení.During the past three decades, human in vitro fertilization (IVF) has changed from disdained technique to one which constitutes a respected branch of modern medicine. Concerns connected with human in vitro fertilization have not materialized. On the other hand, in vitro fertilization has demonstrated benefits in unexpected areas. When combined with techniques of molecular genetics such as preimplantation genetic diagnostics, it can prevent the occurrence of hereditary diseases. In vitro fertilization is greatly needed even in developing countries, despite the fact that the Third World is heavily confronted with the impacts of population explosion.At present, many new and promising biotechnologies are fighting strong opposition from the public. The history of human IVF recurs. Even hypothetical risks are emphasized, and many future benefits are not recognized or cannot be recognized at the present state of knowledge.The significant progress of human IVF provides us with a lesson for the evaluation of impending biotechnologies. The setting of rigid limits or imposing bans on new biotechnologies can significantly restrict the future prosperity of mankind

Influence of organic versus inorganic dietary selenium supplementation on the concentration of selenium in colostrum, milk and blood of beef cows

<p>Abstract</p> <p>Background</p> <p>Selenium (Se) is important for the postnatal development of the calf. In the first weeks of life, milk is the only source of Se for the calf and insufficient level of Se in the milk may lead to Se deficiency. Maternal Se supplementation is used to prevent this.</p> <p>We investigated the effect of dietary Se-enriched yeast (SY) or sodium selenite (SS) supplements on selected blood parameters and on Se concentrations in the blood, colostrum, and milk of Se-deficient Charolais cows.</p> <p>Methods</p> <p>Cows in late pregnancy received a mineral premix with Se (SS or SY, 50 mg Se per kg premix) or without Se (control – C). Supplementation was initiated 6 weeks before expected calving. Blood and colostrum samples were taken from the cows that had just calved (Colostral period). Additional samples were taken around 2 weeks (milk) and 5 weeks (milk and blood) after calving corresponding to Se supplementation for 6 and 12 weeks, respectively (Lactation period) for Se, biochemical and haematological analyses.</p> <p>Results</p> <p>Colostral period. Se concentrations in whole blood and colostrum on day 1 <it>post partum </it>and in colostrum on day 3 <it>post partum </it>were 93.0, 72.9, and 47.5 μg/L in the SY group; 68.0, 56.0 and 18.8 μg/L in the SS group; and 35.1, 27.3 and 10.5 μg/L in the C group, respectively. Differences among all the groups were significant (<it>P </it>< 0.01) at each sampling, just as the colostrum Se content decreases were from day 1 to day 3 in each group. The relatively smallest decrease in colostrum Se concentration was found in the SY group (<it>P </it>< 0.01).</p> <p>Lactation period. The mean Se concentrations in milk in weeks 6 and 12 of supplementation were 20.4 and 19.6 μg/L in the SY group, 8.3 and 11.9 μg/L in the SS group, and 6.9 and 6.6 μg/L in the C group, respectively. The values only differed significantly in the SS group (<it>P </it>< 0.05). The Se concentrations in the blood were similar to those of cows examined on the day of calving. The levels of glutathione peroxidase (GSH-Px) activity were 364.70, 283.82 and 187.46 μkat/L in the SY, SS, and C groups, respectively. This was the only significantly variable biochemical and haematological parameter.</p> <p>Conclusion</p> <p>Se-enriched yeast was much more effective than sodium selenite in increasing the concentration of Se in the blood, colostrum and milk, as well as the GSH-Px activity.</p

Studium ucinku vybranych mykotoxinu u krecika cinskeho (Cricetullus griseus).

Available from STL, Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

Kritické zhodnocení sedmi modelů pro odhad laktační křivky

A mathematical model of the lactation curve approximation provides summary information about dairy cattle production, which is useful in making management and breeding decisions and in simulating a dairy enterprise. Several nonlinear regression models have been devel- oped during the past decades. Unfortunately, there is no unique algorithm in literature. The question of choosing the best function is brought up. We tested seven such models (Gaines, Nelder, Ning-Yang, Marek-Zelinkova, McMillan, Papajesic-Bodero, Wood) using milk yield data of more than 5 000 lactation cycles. Non-linear approximations showed high level of confidence in all models. Critical limitations of individual approaches are discussed using data of several individual cows with problematic approximations. We stress the limitations of individual generally well-fitting mathematical models at the level of individual animals. The best results were obtained with Wood, Nelder or Marek-Zelinkova models.Matematický model pro aproximaci laktační křivky umožňuje získání souhrnných informací o mléčné produkci skotu, což je užitečné při řízení chovu a rozhodování chovatele. V posledních desetiletích bylo vyvinuto několik nelineárních regresní modelů pro popis laktační křivky. Bohužel v literatuře není jednoznačně žádný algoritmus doporučován. Je třeba, aby byla zodpovězena otázka, jak vybrat nejvhodnější funkci. V článku je testováno sedm modelů (Gaines, Nelder, Ning-Yang, Marek-Zelinková, McMillan, Papajesic-Bodero, Wood) na datech z více než 5000 laktačních cyklů. Nelineární aproximace poskytla velkou shodu pro všechny modely. Kritická omezení jednotlivých přístupů jsou diskutována s použitím dat několika jednotlivých krav s problematickými aproximacemi. Kladen je důraz na omezení jednotlivých aproximačních matematických modelů na úrovni jednotlivých zvířat. Nejlepších výsledků bylo dosaženo u Woodova modelu, Nelderova modelu nebo modelu Marka a Zelinkové

Analýza časové řady mléčné produkce

Monitoring of milk yield is used as a tool for the operative management of individual cows as well as management at the herd level. Nevertheless, sometimes a general knowledge of the significance of a particular problem is not sufficient for appropriate managerial decisions and a need arises to weigh up the impact of particular disorder on a particular herd. Than it is necessary to evaluate animal data from a longer period, different lactation order etc. The aim of the introduced research is to present methods for comparing the milk yield of cows in different epochs. The data from selected Holstein dairy herds in the Czech Republic from an 8-year period was used as a model. Several statistical hypotheses (zero trend, absence of seasonal variation) were being tested. The results indicated a requirement to consider the relationship between labour date and milk production. Our statistical analysis enabled us to draw up a table of milk-yield indices showing the average changes in 305-day yield values among lactations and years.Sledování dojivosti mléka se používá jako nástroj pro operativní posuzování jednotlivých krav jakož i hodnocení na úrovni stáda. Nicméně někdy všeobecné znalosti o významnosti konkrétního onemocnění nejsou dostačující pro manažerská rozhodnutí a vyvstává potřeba zvážit jejich dopad na určité stádo. Zde je pak nutné vyhodnocovat data z zvířat v delším období a na různých laktacích. Cílem práce je prezentace metodiky pro porovnání dojivosti krav v různých epochách. Pro sestavení modelu jsou použity údaje holfštýnského stáda z období 8 let. Několik statistických hypotéz (nulovost trendu, absence sezónnost) je testováno. Výsledky ukázaly na vztahy mezi produkcí mléka a datem (epochou). Statistická analýza umožnila sestavit pro produkci mléka tabulku indexů dojivosti, která popisuje změny v průměrných hodnotách 305-denních výnosů v různých laktacích a letech

Indication of social buffering in disbudded calves

Most dairy calves are housed individually in early ontogeny but social housing has positive effects on calf welfare including an advantage of social buffering, i.e., when negative effects of stress are mitigated through social support of conspecific. The effects of social buffering has not yet been examined in relation to disbudding; a painful husbandry procedure commonly performed on young dairy calves. The objective of this study was to investigate the effect of pair versus individual housing on calves’ behavioral reaction to disbudding. In total 52 female calves were randomly allocated either to individual (n = 16) or pair housing (n = 36, 18 focal). Calves were hot-iron disbudded with a local anesthetic and their spontaneous behavior in home pens was recorded for 24 h pre- and post-disbudding. Eating forage, ruminating, resting, exploration, play, self-grooming, and pain-related behaviors were quantified during eight 20 min intervals during the 24 h periods pre- as well as post-disbudding. In pair-housed (PAIR) calves social resting, active and passive allo-grooming were additionally recorded. The differences between individually housed (INDI, n = 10) and PAIR calves (n = 12) were tested by general linear models. The changes in pre- and post-disbudding behaviors in all calves as well as in social behaviors of PAIR calves were tested by paired t-test. We found that head shaking (t =  − 3.46, P = 0.0024), head rubbing (t = 4.96, P < 0.0001) and self-grooming (t = 2.11, P = 0.04) increased in all calves after disbudding. Eating forage increased only in PAIR calves (t = 2.50, P = 0.030) which also resulted in a difference between treatments with PAIR calves fed more often than INDI calves (F(1,18) = 12.96, P = 0.002). Differences in eating forage may be an indication of improved ability of PAIR calves to recover from disbudding. No other significant differences were detected between treatment groups which might have been caused by our limited sample. Our results provide the first evidence that housing treatment affects calves’ reactions to disbudding, with possible indication of social buffering