Evaluation of the transfer of immunoglobulin from colostrum anaerobic fermentation (colostrum silage) to newborn calves.

Colostrum silage is an anaerobic fermentation methodology of excess farm colostrum used to conserve and provide as milk replacement for calves. The present study aimed to evaluate the levels of immunoglobulins present in bovine colostrum silage and its absorption by newborn calves. The concentration of immunoglobulins was determined in fresh colostrum and colostrum silage stored for 12 months. The absorption of immunoglobulins by calves was assessed immediately after birth and 24 h after colostrum silage intake. The immunoglobulin levels were evaluated by ELISA. The results highlighted that colostrum silage kept similar levels of immunoglobulins as the ones in colostrum in natura, and can be transferred to newborn calves with similar amounts to calves fed with colostrum in natura. It is concluded that colostrum silage keeps viable immunoglobulins, and is able to transfer passive immunity to newborn calves.

Protective immunity against tick infestation in cattle vaccinated with recombinant trypsin inhibitor of Rhipicephalus microplus.

The cattle tick, Rhipicephalus microplus, is regarded as the most economically important ectoparasite of livestock globally. Control is achieved primarily through the use of acaricides. This approach is hampered by the development of resistance to commercial acaricides among cattle tick populations. Vaccination against R. microplus infestation is another technology that can be integrated for effective cattle tick control. Proteins belonging to the Kunitz-BPTI family are abundant in cattle tick salivary glands, midgut, and ovaries. These organs are attractive targets for the development of a novel cattle tick vaccine. Efficacy assessment against cattle tick infestation in bovines using a vaccine containing the recombinant form of a member of the Kunitz family from R. microplus produced in a yeast expression system is reported for the first time here. The yeast Pichia pastoris was bioengineered to produce the recombinant version of a trypsin inhibitor that is expressed in cattle tick larvae (rRmLTI). Immunization with rRmLTI afforded 32% efficacy against R. microplus. The estimated molecular weight of rRmLTI was 46 kDa. Structural homology to the native form of the larval trypsin inhibitor was documented by recognition of rRmLTI in Western-blots using polyclonal antibodies from mice immunized with cattle tick larval extract or rRmLTI. Bioinformatics analysis of the partial nucleotide and deduced amino acid sequences indicated that the rRmLTI closely resembles BmTI-6, which is a three-headed Kunitz protein present in cattle tick ovary and fat tissue.