Total litter loss

Some litters may have 100% postimplantation loss, known as total litter loss or total resorption. This may represent an extreme case of increased postimplantation loss, particularly when many litters show such an increase however, it may also represent a separate, and sometimes incidental, phenomenon. For some substances, the effect is an all-or-none effect. 

Where the total litter loss is judged as an extension of other increased postimplantation loss, the mean values should include total litter loss. For the other cases, it is acceptable to exclude litters with total litter loss however, those instances of total litter loss should be addressed in the text of the results, particularly when there is an all-or-none effect. The decision on whether to present group means including or excluding total litter loss will depend on the above considerations presentation of both means may lead to confusion rather than enlightenment. 

For all but the rarest events such as malformations, abortions or total litter loss, the evaluation of between 16 and 20 litters for rodents and rabbits tend to provide consistency between studies. Below 16 litters per group for evaluation, the study results become inconsistent, whereas more than 20-24 litters per group do not enhance the consistency and precision of the study data. Therefore, and considering a certain non-pregnancy rate, generally 20-24 animals per sex are used per group. 

The C-section ( litter ) values, i.e., gravid uterus weight, corpora lutea, total number of implants, and numbers of live and dead implants (including separate categories of dead implants) are presented as means, together with an indicator of variation, typically standard deviation. Additionally, pre- and postimplantation losses are calculated for each female ... 

Kauffman et al. (1994) estimated the fuel loads along a vegetation gradient from campo limpo to cerrado sensu stricto near Brasilia. In the cerrado only 27% of the fuel load of 10 Mg ha" was comprised of graminoids the remainder was deadwood and leaf litter. They estimated the nutrient pools in combustible components in the cerrado sensu stricto to be 54.7 kg ha" N, 13.8 kg ha K, 3-5 kg ha P, and 30.5 kg ha" Ca. They concluded that the total biomass of the herbaceous layer of the cerrados was similar to that of other savanna ecosystems. The authors concluded that any loss of N due to fire was negligible compared to the N pool in the soil. Biological N fixation and precipitation inputs would compensate for such losses. Similarly, precipitation inputs would compensate for the loss of P, K and Ca (Schiavini 1983, Coutinho 1979, Pivello-... 

Fig. 7.1 Total nutrient stocks and in plant biomass plus soil in rain forest, newly planted Pinus caribaea (6 months old), P. caribaea, and Gmelina arborea plantations at the end of the first rotation (9.5 and 8.5 years old, respectively), and second rotation P. caribaea (1.5 years old) at Jari (Sanchez et al. 1985). H = harvest loss from trees taken when clearing the rain forest for the plantations L = leaching. Total nutrient stock is defined as the sum of all the nutrients in plant biomass (aboveground, litter, detritus, roots) plus total N, available P (extracted by the Mehlich method), and exchangeable K, Ca, and Mg in the top meter of the soil.

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