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Dissertação
Novilhas de Corte Suplementadas a Pasto sob Efeito da Imunocastração.
The objective of this work was to evaluate the effect of immunocastration and the use of mineral supplementation with grain, on Massai grass pastures (Megathyrsus maximus) during the rainy season, on the performance, blood biochemical profile and carcass and meat characteristic of ½ Nelore X L...
Autor principal: | Loureiro , Leide Karla Ribeiro |
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Grau: | Dissertação |
Idioma: | pt_BR |
Publicado em: |
Universidade Federal do Tocantins
2023
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Assuntos: | |
Acesso em linha: |
http://hdl.handle.net/11612/6010 |
Resumo: |
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The objective of this work was to evaluate the effect of immunocastration and the use
of mineral supplementation with grain, on Massai grass pastures (Megathyrsus
maximus) during the rainy season, on the performance, blood biochemical profile and
carcass and meat characteristic of ½ Nelore X Limousin heifers. Twenty-eight animals
were used, with mean age and initial weight of 13 months and 217 kg, respectively. A
completely randomized design with four treatments distributed in a 2 x 2 factorial
arrangement was used, two sexual conditions (immunocastrated and non-castrated)
and two types of supplementation (mineral supplementation with grain and common
mineral). The mineral supplement with grain and the common mineral supplement
were supplied in quantity 75 g and 25 g/100 kg body weight, respectively. The
immunocastration method consisted of two doses (initial and booster) of the anti-GnRH
vaccine Bopriva®, 1 ml in each animal belonging to this treatment, administered
subcutaneously. At the end of the experiment the animals were taken to the
commercial slaughterhouse located in the city of Araguaína-TO. The slaughter took
place following the standards of the industry. Heifers were approximately 18 months
old and had no definitive tweezers (zero tooth). There was interaction (P<0.10) of the
factors studied for the variables of final body weight and total weight gain, in which the
immunocast heifers supplemented mineral supplement with grain promoted lower
FBW and TWG (324.27 and 106.57, respectively), compared to uncastrated heifers,
and equally supplemented (342.86 and 126.86 kg, respectively). The mean daily gain
was influenced by the sexual status (P<0.10), in which immunocastration in heifers
resulted in lower performance when compared to uncastrated heifers (0.788 vs 0.860
kg/day). Sexual condition and type of supplement did not influence serum levels of
glucose, triglyceride, albumin, total protein and creatine. However, there was
interaction (P<0.10) between the factors studied for alkaline phosphatase, cholesterol,
plasma urea, alanine aminotransferase enzyme and aspartate aminotransferase. The
uncastrated heifers that received mineral supplementation with grain showed higher
serum levels of urea than the other treatments. There was interaction (P<0.10)
between the type of supplement and the sexual condition for ribeye area and hot
carcass weight, in which the immunocast heifers treated with common mineral
supplement presented higher RA (63.72 cm2
) in compared to uncastrated heifers also
supplemented with common mineral (55.80 cm2
). Immunocast heifers that received
mineral supplementation with grain obtained lower HCW (167.07 kg) compared to non immunocastrated heifers equally supplemented (174.71 kg). The method of
immunocastration associated with the mineral supplement with grain provided a mean
of 4.67 kgF/cm2
for shear force, being the only treatment to reach classification of soft
meat, according to the literature. The uncastrated heifers receiving a mineral
supplement with grain had a lower index of yellow of the meat, but all the treatments
maintained the coloration of the appropriate meat. The use of immunocastration
associated with the mineral supplement with grain provides a lower of hot carcass
weight, however, does not affect its yield and allows the production of quality meat. |