To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
A genealogical and a viability analysis was carried out on the 1559 available registers for the Conservation Nucleus of Brazilian Bergamasca sheep of the University of Brasilia farm in Brazil using the ENDOG and the Vortex programs. To run the ENDOG it was used the registered data and for the Vortex it was used information obtained by a questionnaire answered by the curators of the herds. Of the animals registered, 767 had known parents, with significantly more dams known at each generation. The number of pedigrees known has increased over the generations, with higher registration of parents of sires than dams. The Computed Mean Inbreeding calculated by ENDOG was 0.29 percent and mean average relatedness was 1.52 percent. Mean Generation interval was 3.71 years with this values being lower for sires than dams. The population probability of extinction, calculated by Vortex was 17 percent and the average time to extinction was 59 years. Forty-two additional scenarios were created to determine which factors most threaten these populations which were frequency of catastrophes, lack of animal entrance and adult and lamb mortalities, especially adult female mortality. These results indicate that future breeding plans should include exchange of sires between farms to maintain low inbreeding levels and increase genetic variability and upgrade the management to control the mortality rates of animals.
The purpose of the current work was to study phosphorus (P) metabolism in growing sheep supplemented with different levels of dicalcium phosphate using an extant mathematical model. Twelve male non-castrated Santa Inês sheep, weighing 23 (±2·2) kg, received a basal diet unsupplemented or supplemented with dicalcium phosphate to provide 1·5, 3·0, 4·5 g of P/animal per day (treatments T1 to T4, respectively). After 3 weeks adaptation, 7·4 MBq of 32P was injected into the jugular vein of each animal. Samples of blood, faeces and urine were collected every day during a 7-day period and thereafter the animals were sacrificed and samples from liver, kidney, heart, muscle and bone were collected for specific activity and inorganic P determinations. The flows between gut and plasma were similar for each treatment except for T1, which showed the lowest values for both flows (P<0·05). The amount of P accreted to soft tissue (F42) was different among treatments, however net tissue retention was similar for all treatments. Total P retained was highest for T4 and lowest as well as negative for T1 and T2. Phosphorus accreted to bone (F32) was different among treatments and contributed to the different net bone retentions. The highest value of F32 was reached by animals on T4, whilst the lowest values were found for animals on T1. Despite having the highest value of F32, it should be noted that animals on T4 excreted the most P in faeces. Considering concerns about environmental P pollution, it is important to be aware that the treatment which provided the highest value for net bone P retention and for F42 also led to the highest value of P excreted in faeces. Therefore, the current study suggests that T3 provided the best P level for this category of animal since P accreted to bone and tissue indicated that P absorption was adequate to attend to P requirements.
The isotope dilution technique is the most important way to study the metabolism of minerals. With the use of radiophosphorus (32P), it is possible to describe the kinetics of P including the endogenous fraction. The aim of this work was to study the metabolism of supplemented P using the isotope dilution technique and to apply bio mathematical model to investigate its kinetics.
Researches worldwide have been studying ruminal methane production in vitro and the in vitro gas production technique has demonstrated an ability to predict the in vivo enteric methane production from ruminants (Getachew et al., 2005; Tavendale et al., 2005). Studies of rumen microbial ecology in animals fed with tannin rich plants have demonstrated that tannins can affect rumen ecology. The objective of this study was to measure methane (CH4) production of Brazilian tannin rich plants incubated in vitro.
Tannins are secondary compounds that can bind protein and other nutrients and reduce their availability to the animals. Polyethylene glycol (PEG) has a great affinity with tannins and when it is added to the feed it is bound to tannins and releases the protein and other nutrients. There is no information about the amount of PEG that is needed to obtain the maximum precipitation of tannin and the minimum tannin effect. Some assays are conduced using doses of PEG according to the tannin content, but the activity of tannins can vary and this imply that the tannin analysis has to be done prior. The aim of this work was to evaluate doses of polyethylene glycol to minimize the effect of tannins on rumen fermentation.
Anti nutritional factors in tropical legumes are very common and the chemical analysis for tannins has become an important tool to evaluate alternative ruminant feeds in the tropics. However, frequently results from tannin chemical analysis are not in agreement with biological response when animals are fed those feeds. There is a lack of information concerning the biological effects (activity or reactivity) of tannins on ruminants. Usually the effects of tannins are tested in vitro by adding compounds with capacity of biding tannins. The aim of this work was to compare two binding compounds to evaluate the effect of tannins of tanniniferous feeds for ruminants.
The chemical determination of tannins has become inefficient to predict the negative effects in nutritional parameters. Apparently, different tannins have distinct activity (or reactivity) resulting in anti nutritional effects. The objective of this work was to test three compounds to establish a curve of biological equivalent effect of tannins using the in vitro gas production technique.
Haemonchosis in cattle represents one of the biggest problem in Brazil, where an wide variations in dietary protein can be observed in pastures throughout the year. It is thought that this variation in protein intake might have influences on the impact of the parasite host metabolism arid productivity. This experiment was conducted to investigate the influence of dietary protein and the infection with Haemonchus placet upon parasitological parameters in growing calves.
Email your librarian or administrator to recommend adding this to your organisation's collection.