L.F.G. Menezes

Características dos componentes não integrantes da carcaça de novilhos superjovens da raça Devon, terminados em diferentes sistemas de alimentação

O objetivo do estudo foi avaliar as caracteristicas dos componentes nao integrantes da carcaca de novilhos Devon terminados em confinamento (CONF), em pastagem de clima temperado (pastagem de azevem - Lolium multiflorum Lam - PTEM) ou em pastagem de clima tropical (associacao de pastagem de milheto - Pennisetum americanum (L.) Leeke - e capim-papua - Bracharia plantaginea - PTRO). Os novilhos, ao inicio da terminacao, estavam com 320kg e 15 meses de idade. Os animais confinados foram alimentados com relacao volumoso:concentrado de 60:40; o volumoso era constituido de silagem de milho, e o concentrado de farelo de trigo, milho e minerais. Os animais foram abatidos com pesos semelhantes de 388,3; 386,7 e 375,8kg no CONF, na PTEM e na PTRO, respectivamente. Os animais da PTRO apresentaram maior (P<0,10) rendimento de carcaca quente (RCQ) relativo a 100kg de peso corporal vazio (RCQPCV) do que os da PTEM, 64,6 versus 62,6%, e os do CONF apresentaram RCQPCV intermediario, 63,7%. Os pesos absolutos do figado, 5,22; 4,43 e 3,87kg, do conjunto dos orgaos internos, 12,81; 11,37 e 10,83kg, do rumen-reticulo, 7,62; 6,54 e 6,06kg, da gordura do coracao, 1,26; 0,65 e 0,30kg, e dos intestinos, 9,97; 7,13 e 7,49kg, foram mais altos (P<0,05) nos animais da PTEM, em relacao aos do CONF e da PTRO, respectivamente. A mesma ordem de grandeza ocorreu com os pesos relativos desses orgaos. A PTRO e o CONF originaram animais com maior (P<0,05) peso de conteudo gastrintestinal em relacao a PTEM, respectivamente, 60,27; 55,32 e 41,21kg. O CONF proporcionou animais com pesos absolutos mais elevados (P<0,05) do omaso, 5,17kg, em relacao aos da PTEM, 3,70kg, e este peso foi intermediario nos animais da PTRO, 4,77kg. A mesma ordem de grandeza ocorreu com os pesos relativos do omaso, 1,61; 1,12 e 1,54%.

Perfil de ácidos graxos na carne de novilhos Charolês e Nelore puros e de gerações avançadas do cruzamento rotativo, terminados em confinamento

The objective of this research was to evaluate the heterozygosis and genetic group effects on fatty acids profile of feedlot finished steers, straightbreds (Charolais - C and Nellore - N), and crossbreds from second (G2) (¾C ¼N and ¾N ¼C), third (G3) (5/8C 3/8N and 5/8N 3/8C) and fourth (G4) (11/16C 5/16N and 11/16N 5/16C) generation of rotational crossbreeding. The Nellore and 11/16N 5/16C meat showed higher proportion of myristic acid (C14:0) in relation to Charolais and 11/16C 5/16N meat, respectively. On the other hand, the meat of the 11/16C 5/16N steers showed higher presence of heptadecanoic acid (C17:0) and arachidonic acid (C20:4 n6) in relation to 11/16N 5/16C. The 3/4C 1/4N steers of G2 which were superior in stearic acid (C18:0) and linoleic acid (C18:2 n6c) in the total polyunsaturated fatty acids participation studied and in the ratio between polyunsaturated and saturated fatty acids, while the 3/4N 1/4C showed superiority in oleic acid (C18:1 n9c). In G3 the meat of the 5/8C 3/8N steers showed superiority in the stearic and elaidic acids (C18:1 n9t) and in the total saturated fatty acid, while the 5/8N 3/8C steers showed higher participation of the meristoleic (C14:1), cis-10-heptadecanoic(C17:1) and oleic acids and total unsaturated fatty acids. The heterosis was significant in the G2 for C17:0, C18:0, C18:1 n9c, C18:2 n6c, in the total saturated, unsaturated and polyunsaturated fatty acids. The 3/4C 1/4N steers showed the healthiest meat among the genetic groups studied, with higher presence of polyunsaturated fatty acids and higher polyunsaturated: saturated ratio.

Características da carcaça e do corpo vazio de bovinos Charolês de diferentes categorias abatidos com similar grau de acabamento

The carcass characteristics and empty body of Charolais steers n=9, cull heifers n= 10, and cull cows n=10, feedlot finished with similar subcutaneous fat thickness were evaluated. The slaughter weight and empty body weight (EBW) were similar between steers (480.2 and 417.4kg) and cows (516.2 and 405.8kg), which were higher than for heifers (368.3 and 306.1kg). Hot carcass dressing was significantly different among categories, being 57.2, 53.3 and 50.5%, respectively, for steers, heifers and cows. When carcass dressing was expressed in relation to EBW the differences became smaller among categories, being significant only between steers and heifers. The digestive tract content of cows was 34 and 45% higher than for steers and heifers, respectively, being correlated (P<0.05) with slaughter weight (r=0.66) and hot carcass dressing (r=-0.41). Hot carcass weight was similar for steers (274.9kg) and cows (260.8kg), both superior to heifers (196.4kg). Carcass length was higher for cows, intermediate for steers and lower for heifers. The Longissimus dorsi area was smaller for heifers. Steers showed better carcass conformation score than females, which did not differ between themselves.

Frequências do fornecimento do alimento no desempenho de vacas e novilhas em confinamento

The effect of frequency of supply of forage (V) and concentrate (C) on the performance of cows and heifers in feedlot was studied. The treatments were the following frequencies in the supply: 2 V/C= V and C twice daily; 1 V/C= V and C once daily; 1 V/2C= once V and C twice daily, 1 V/3C= once V and C three times a day, for the cows or heifers. The experimental design was completely randomized in factorial arrangement 4 x 2, with four replications. There was no significant interaction between frequency of supplying and category animal. The dry matter intake (DMI) was superior for the animals fed 1 V/2C or 1 V/3C a day in relation with the supply of 2 V/C and 1 V/C, presenting values of 11.7; 11.4; 10.6 and 10.7 kg, respectively. The average daily gain (ADG) was not influenced by the frequency of supplying. The DMI was higher in cows (12.6 kg) than heifers (9.57 kg), having no difference in the weight gain. Increasing frequency of feeding the concentrate to two or three times a day, provided greater consumption, not influencing the weight gain of cows and heifers confined.

Desempenho de vacas de descarte recebendo dietas com ou sem monensina

The feedlot performance of beef cull cows receiving diets without or with monensin (200mg animal -1 day -1 ), was evaluated. The diet, 48% of roughage and 52% of concentrated, contained 12.5% of crude protein and 2.99Mcal of digestible energy kg-1 of dry matter. The intake of dry matter and digestible energy was reduced 20.9% with the presence of monensin in the diet. The reduction in digestible energy intake by the animals fed with monensin affected negatively their performance, causing a decrease of 22.6% in their weight gain. With higher food intake and consequently superior performance, the control animals presented higher live weight at slaughter (527.49 vs 498.00kg), being 5.8% heavier in relation to the animals fed with monensin. The feed:gain ratio and energy efficiency, were not affected significantly by the presence of monensin in the diet (being the averages 7.78 and 23.24, respectively). The presence of monensin in diet resulted in reductions of dry matter intake and weight gain, however, it did not alter the feed:gain ratio.

Performance of feedlot steers finished with different fat sources in diet

The objective of this study was to evaluate the effect of different fat sources in finishing diets on performance of feedlot steers. Twenty steers, with average age of 20 months and initial live weight of 260 ± 41.3 kg, were feedlot fed during 126 days. The animals received corn silage as roughage and the tested concentrates were: basic concentrate (BC); basic concentrate + whole rice bran and rice oil (WRB); basic concentrate + 3 % of fatty acids calcium salts (M3) and basic concentrate + 6 % of fatty acids calcium salts (M6). Each treatment had animals with the following genetic group: 1 pure Charolais (CH), 1 pure Nellore (NE), 2 11/16 CH 5/16 NE, 1 21/32 NE 11/ 32 CH. No significant differences were observed for crude protein, digestible energy, neutral and acid detergent fibers intakes. The animals that consumed 6 % of fatty acid calcium salts presented higher ether extract intake (0.77 kg/day), while those that consume 3 % or whole rice bran and oil showed intermediate value (0.51 kg/day) and the ones that consumed basic concentrated presented lower value (0.25 kg/day). Similar averages were observed for average daily weight gain (1.142, 1.199, 1.365 and 1.391 kg/day, for BC, WRB, M3 and M6, respectively) and final weight (421 kg).

Caracterização bromatológica de silagens de milho de genótipos super precoce

The annual availability of corn genotype is very large, requiring a proper assessment to be indicated for the production of silage. The aim of this study was to evaluate the chemical characteristics of corn genotypes for silage production, and assess whether the grain genetic basis or hardness may change the indication of corn cultivars for silage. The experiment was conducted at the experimental area of the Universidade Tecnologica Federal of Parana, in the randomized block design, evaluating 30 genotypes of experiment Super Early South. It was evaluated the chemical characteristics of the genotypes and, after they were grouped according to the characteristics of genetic basis and of grain texture. It was found that the genotypes of the experiment South Super Early cannot be differentiated according to the genetic basis of grain and texture for all traits. However, they can be distinguished by the dry matter silage.

Metabólitos sanguíneos de vacas de corte suplementadas ou não com sais de cálcio de ácidos graxos durante o período pré e/ou pós-parto

The study evaluated the blood metabolites of beef cows maintained on native pasture supplemented with calcium salts of fatty acids (CSFA) during 45 days pre-partum (PRE); supplemented with CSFA during 45 days pre-partum and 63 days post-partum (PREPOS); supplemented with CSFA during 63 days post-partum (POS) and cows not supplemented (PN): without supplementation. Blood samples were taken 64 days pre-partum, and at 21, 42 and 63 days post-partum. No significant interaction was observed between treatment and period. Plasma concentrations of β-hydroxybutyrate (βHB), triglycerides, cholesterol, glucose and urea were not affected by protected fat supplementation. The regression analysis showed significant linear decline of blood triglycerides (TRIG) concentration with the increase of milk production (PL) for PN cows (TRIG= 23.10 - 2.18*PL, R2= 0.31) and quadratic effect for PRE cows (TRIG= 6.54 - 1.75*PL + 0.30*PL2, R2= 0.62). For cows submitted to the POS and PREPOS treatments there was no effect of milk production on blood triglycerides concentration, indicating that CSFA during milk production aids the maintenance of a positive energetic balance. The concentration of plasma cholesterol increased while the concentrations of triglycerides and urea decreased linearly until the end of the experiment.