Sodium selenite is used to prevent selenium deficiency known as nutritional muscular dystrophy or white muscle disease. In ruminants, selenium supplements are transformed partiality in insoluble form by ruminal microorganisms and its process decrease the selenium absorption in digestive gastrointestinal. However, the objective in this research was focused in encapsulated sodium selenite to be release into of a pH less than four, similarity to an intestinal environment. It was encapsulated by nanoprecipitation and emulsion–evaporation methods, within polymeric nanoparticles. The effect of these methods, polymer proportion (Eudragit RL and RS) and solvent (ethanol and acetone) on the physicochemical (drug entrapment, polidispersity index (PDI) and z potential) and morphological characteristics (particle morphology and particle size) were evaluated. Particle size from each nanoparticles, formulation ranged from 36.64 to 213.86 nm. Particle size, z potential and PDI increased (P ≤ 0.01) when nanoprecipitation and ethanol were used. No significant differences (P > 0.05) were observed when different polymeric proportions were used. Selenium entrapment was 26% when emulsion–evaporation method was used and 78% with nanoprecipitation. Nanoparticles produced by nanoprecipitation were spherical and had a great variation in particle size; on the other hand, nanoparticles produced by emulsion–evaporation were spherical as well as amorphous and presented a homogeneous nanopartcicle size distribution. The release of selenium from nanoparticles was higher in acid pH (less than 4), this condition may represent a better availability of the mineral in the small intestine.

Using ammonium sulfate, three levels of dietary S (.15, .20, and .25%, DM basis) were evaluated in a finishing trial with 108 yearling crossbred heifers (384 kg). The basal diet contained (DM basis) 4% alfalfa hay, 6% sudangrass hay, 74% steam-flaked corn, 4% yellow grease, 6% cane molasses, and 6% protein-mineral supplement. Increasing dietary S decreased ADG (quadratic effect, P < .10), DMI (linear effect, P < .10), feed efficiency (quadratic effect, P < .10), diet NE (quadratic effect, P < .10), and longissimus muscle area (linear effect, P < .05). Six Holstein steers (218 kg) with cannulas in the rumen and proximal duodenum were used to evaluate treatment effects on characteristics of digestion. Treatment effects on ruminal and total tract digestion of OM and N were small (P > .10). However, ruminal digestion of ADF and starch was slightly lower (quadratic effect, P < .10), and postruminal digestion of ADF and starch was correspondingly greater (quadratic effect, P < .05) with supplemental S. Dietary S level did not influence (P > .10) ruminal synthesis of microbial N. Increasing dietary S did not influence (P > .10) ruminal pH or lactic acid. Increasing S decreased molar proportions of acetate (quadratic effect, P < .10) and increased molar proportions of propionate (linear effect, P < .10). We conclude that S in excess of .20% of dietary DM may have detrimental effects on growth performance and dietary NE. Excessive dietary S may also compromise carcass merit by decreasing longissimus muscle area.

This study discusses scientific findings on the use of draught animals such as equids (i.e., horses, mules, and donkeys) and bovids (i.e., cattle and water buffaloes) in rural labours. Relevant peer-reviewed literature published between 1980 and 2021 was retrieved from CAB Abstracts, PubMed, ISI Web of Knowledge, and Scopus databases. Although animals were used to produce draught power since their domestication and are still being used for this purpose, mechanisation has markedly reduced animal labour demand in agriculture. However, the process was uneven across continents according to economic constraints, and draught animals are currently concentrated in small production units located on terrains that do not favour agriculture mechanisation in Africa, Latin America, and Asia. Generally, equids can work at rates similar to those of bovids or faster but can sustain the work for shorter periods of time. In addition, buffaloes possess tough hooves and resistance to disease that make them suitable for working in wetlands and clay soils. Draught animals allow a marked reduction of both GHG emissions and non-renewable energy consumption as compared with agricultural machinery. In addition, they may allow obtaining profits from otherwise non-usable lands. Therefore, their use should be promoted in rural areas where low investments are usually the only ones feasible, and the energy of the animals can be obtained at a low cost by feeding them harvest residues and by-products. However, more attention should be paid to the quality of human–animal interactions—due to the close contact between animals and humans while working—and to the welfare of draught animals when transported and slaughtered—due to the high prevalence of injuries they suffer when subjected to these practices.

Three experiments were carried out to determine the optimum selenium-vitamin E injection level to maintain acceptable blood selenium (Se) status of does and kids, as well as to determine the relation of that status to mortality rates in kids. In experiment 1, 238 goats were assigned to one of three groups during the mating period: A1-control, A2- 0.06mgSe+0.8IU vitE/kgBW and A3-0.125mgSe+1.7IU vitE/kgBW. No differences (P>.05) for fertility and prolificacy were observed among the groups. Blood Se concentration did not differ among Se-vit E groups and control group before injection, and both groups showed Se deficient condition. There was a trend (P<.05, 32%) to increase Se blood level 60 days post-treatment, but difference was not observed between A2 and control groups, while difference (P<.05; 103%) was observed between A1 and A2 groups vs high Se injection (A3 group). In experiment 2, 48 goats were divided into four groups: B1- control, B2- 0.125mgSe+1.7IU vitE/kgBW, B3- 0.25mgSe+3.4IU vitE/kgBW and B4- 0.31mgSe+4.2IU vitE/kgBW. The B4 group reached the highest concentration at the third month after injection (0.11 ppm), then started to decline after 100 days, reaching a value slightly higher than B2 and B3 on the 135th day of pregnancy. Results of B2 and B3 groups were slightly higher that those of B1 (P<0.05). In experiment 3, 194 kids (3 to 7 days postpartum) born from Se-deficient goats were used to compare the effectiveness of Se injection. They were divided into three groups: C1- control, C2- 0.3mgSe+4.2IU vit E/kg BW and C3- 0.6mgSe+8.4IU vit E/kg BW. C1 showed the highest percentage of mortality (60%) as compared to treated Se groups, that scored equal percentage of deaths (22% averaged). The concentration of Se in blood, on day 20th after the onset of the treatment rapidly increased, according with level of Se injection. The 0.3mgSe/kgBW Se injection increased the blood Se concentration in pregnant goats and it was effective to prevent white muscle disease lesions, besides enhancing the survival of kids until weaning.