Papers by Mario Chizzotti
Animal Production Science, 2014
The mechanistic model contains state variables for cellulolytic hexose, amylolytic hexose, cellul... more The mechanistic model contains state variables for cellulolytic hexose, amylolytic hexose, cellulolytic pyruvate, amylolytic pyruvate, cellulolytic microbes, amylolytic microbes, acetate, propionate, butyrate, H 2 and methanogens, and a zero-pool for CH 4. Flux equations are described by Monod and mass-action forms. Results and discussion This model permits the interpretation and quantification of rumen metabolic pathways yielding acetate, propionate, butyrate, H 2 and CH 4. Predicted propionate and CH 4 yield per unit of feed increased and decreased, respectively, in response to higher hexose inflow, which reflects a diet with more rapid degradable carbohydrates. Further, improvement of predicted CH 4 production might be achieved to extend the model with a separate state variable for protozoa, affecting the partition of the metabolic pathways. The present modelling effort provided the integration of existing knowledge on rumen metabolic pathways and reproduced observations on VFA profile and CH 4 production.
Nutrient requirements of Nellore cattle, purebred and crossbred, of different sexual groups
ABSTRACT
Usando Modelos Matemáticos Nutricionais Para Aumentar a Eficiência Em Gado De Corte
ABSTRACT
Revista Brasileira de Zootecnia
RESUMO-Avaliaram-se o consumo e a digestibilidade total dos nutrientes e o desempenho de novilhos... more RESUMO-Avaliaram-se o consumo e a digestibilidade total dos nutrientes e o desempenho de novilhos Nelore recebendo dietas contendo silagens de capim-braquiarão e de sorgo como fonte de volumoso nas proporções de 100:0, 67:33, 33:67 e 0:100, com base na matéria seca. Foram utilizados 24 novilhos Nelore, castrados, com peso médio inicial de 380 kg, distribuídos em um delineamento em blocos casualizados, com seis repetições, recebendo 60% de volumoso e 40% de concentrado, com base na matéria seca. O ensaio teve duração de 78 dias-15 dias de adaptação seguidos de três períodos de 21 dias. Os consumos médios de matéria seca (MS), matéria orgânica (MO), proteína bruta (PB), extrato etéreo (EE), carboidratos não-fibrosos (CNF) e nutrientes digestíveis totais (NDT), assim como a taxa de passagem, aumentaram linearmente com o incremento da silagem de sorgo nas dietas. Tendência semelhante foi observada para o ganho de peso médio diário, estimando-se acréscimos de 0,00313 kg/unidade de silagem de sorgo adicionada. As digestibilidades totais de MS, MO, PB e fibra em detergente neutro (FDN) também apresentaram comportamento linear crescente com o incremento dos níveis de silagem de sorgo. Contudo, as digestibilidades aparentes do EE e dos CNF não foram influenciadas pelas dietas, registrando-se, respectivamente, valores médios de 80,1 e 89,5%. A associação de 67% de silagem de sorgo e 33% de silagem de capim-braquiarão consistiu em como boa alternativa de volumoso para a alimentação de novilhos Nelore, uma vez que promoveu consumo e ganho de peso próximos aos observados para a dieta contendo apenas silagem de sorgo. Palavras-chave: confinamento, fibra em detergente ácido indigestível, produção
Calpastatin activity and beef tenderness of Nellore and Angus cattle fed two feeding strategies
Calpastatin activity was measured on longissimus muscle of 17 Nellore and 17 Angus cattle fed two... more Calpastatin activity was measured on longissimus muscle of 17 Nellore and 17 Angus cattle fed two different diets. Cattle were randomly assigned into one of the following feeding strategies: 100:0 concentrate:roughage ratio (9 Nellore and 9 Angus) and 70:30 concentrate:roughage ratio (8 Nellore and 8 Angus) fed ad libitum. Longissimus muscle (LM) samples were collected 24 h postmortem and calpastatin activity measured. In order to validate calpastatin results, Warner-Bratzler shear force (WBSF) and myofibrillar fragmentation index (MFI) were performed on longissimus muscle samples also collected 24 h postmortem from each animal. Higher calpastatin activity was observed on LM from Nellore cattle (P = 0.0238). This result was confirmed by the lower values of MFI on LM of Nellore cattle (P = 0.0001) which led to a greater WBSF value (P = 0.0026) of Nellore compared to Angus Beef. Calpastatin activity was not affected by feeding management (P = 0.8437). Similarly, no differences were ob...
PLOS ONE, 2015
Background Beef cows herd accounts for 70% of the total energy used in the beef production system... more Background Beef cows herd accounts for 70% of the total energy used in the beef production system. However, there are still limited studies regarding improvement of production efficiency in this category, mainly in developing countries and in tropical areas. One of the limiting factors is the difficulty to obtain reliable estimates of weight variation in mature cows. This occurs due to the interaction of weight of maternal tissues with specific physiological stages such as pregnancy. Moreover, variation in gastrointestinal contents due to feeding status in ruminant animals is a major source of error in body weight measurements. Objectives Develop approaches to estimate the individual proportion of weight from maternal tissues and from gestation in pregnant cows, adjusting for feeding status and stage of gestation. Methods and Findings Dataset of 49 multiparous non-lactating Nellore cows (32 pregnant and 17 non-pregnant) were used. To establish the relationships between the body weight, depending on the feeding status of pregnant and non-pregnant cows as a function of days of pregnancy, a set of general equations was tested, based on theoretical suppositions. We proposed the concept of pregnant compound (PREG), which represents the weight that is genuinely related to pregnancy. The PREG includes the gravid uterus minus the non-pregnant uterus plus the accretion in udder related to pregnancy. There was no accretion in udder weight up to 238 days of pregnancy. By subtracting the PREG from live weight of a pregnant cow, we obtained estimates of the weight of only maternal tissues in pregnant cows. Non-linear functions were adjusted to estimate the relationship between fasted, non-fasted and empty body weight, for pregnant and non-pregnant cows.
Asian-Australasian journal of animal sciences, 2013
The objectives of this study were to compare visual observation and an electronic grazing time me... more The objectives of this study were to compare visual observation and an electronic grazing time method and to evaluate the effects of nutritional plans on intake, grazing behavior and horizontal and vertical locomotion of young bulls in a tropical pasture. Thirty-nine Nellore young bulls with an average body weight of 345±9.3 kg kept in pasture were used. The experimental treatments consisted of: restricted: animals kept in a plot with a low mass of forage receiving mineral mixture only; control: animals receiving mineral mixture only; HPHC: a high protein and high carbohydrate supplement; HPLC: a high protein and low carbohydrate supplement; LPHC: a low protein and high carbohydrate supplement; LPLC: a low protein and low carbohydrate supplement. GPS collars equipped with activity sensors were used. Information about head position, latitude, longitude and altitude were recorded. Daytime grazing behavioral patterns monitored by a continuous focal animal recording method was compared ...
Effect of diet without forage on beef quality in Bos Taurus and Bos Indicus young bulls
ABSTRACT Abstract Text: The objective was to evaluate beef quality of finishing young bulls Nello... more ABSTRACT Abstract Text: The objective was to evaluate beef quality of finishing young bulls Nellore or Aberdeen Angus fed a whole grain corn diet without roughage (WR, 85% of whole corn and 15% of commercial pellet) or a traditional diet containing 30% of corn silage and 70% of concentrate (30:70). Thirty-six animals, with average initial body weight of 381.2 ± 11.87 kg, were used in a 2 x 2 factorial design (2 breeds and 2 diets). Both diets had 12.5% crude protein and 2.88 Mcal/kg of ME. Animals were fed for 82d after a 28d adaptation period and slaughtered at the end. Samples were taken from the Longissimus dorsi muscle between the 12nd and 13rd ribs for centesimal composition analyses, color (L*, a*, b*), cooking weight loss (CWL) and shear force (SF). The model included the effects of breed, diet and their interaction and was analyzed using PROC GLM in SAS 9.1. The moisture, ashes, protein, CWL, a * and b * were not affected by breed and diet. However, Angus bulls showed higher muscle ether extract in WR than Nellore animals. Angus animals showed greater tenderness when compared to Nellore, and WR had a tendency to increase tenderness. Nellore presented a higher brightness (L *) when compared to Angus animals. Angus animals and diet with whole grain corn increased the levels of ether extract and the use of Angus animals improved meat tenderness. Table 1. Centesimal composition (%), color (L*, a*, b*), cooking weight loss (CWL), and shear force (SF) of beef from young bulls Nellore and Angus receiving diets with or without roughage. Atributes Nellore Angus SEM P Value 30:701 WR2 30:70 WR Breed Diet B*D Moisture (%) 73.7 74.4 73.9 73.51 1.08 0.77 0.88 0.56 Ashes (%) 1.2 1.2 1.2 1.3 0.15 0.81 0.61 0.87 Protein (%) 17.1 16.7 17.0 17.2 0.20 0.82 0.88 0.67 Ether extract (%) 4.9 4.1 4.1 6.2 0.04 0.04 0.05 <.0001 CWL(%) 27.4 27.4 27.7 25.6 1.58 0.30 0.11 0.14 SF (Kgf) 6.0 5.8 5.8 5.2 0.47 0.05 0.07 0.41 L* 49.2 48.7 48.3 47.7 0.51 0.02 0.97 0.56 a* 7.3 7.5 7.7 7.8 0.48 0.16 0.44 0.92 b* 9.7 9.5 9.4 9.2 0.42 0.1003 0.2745 0.8556 1 Diet containing 30% roughage and 70% concentrate (30:70); 2 diet with 85% corn grain and 15% commercial pellet (Without roughage, WR). Keywords: color, shear force, beef
Exigências nutricionais de energia para bovinos de corte
ABSTRACT
Animal, 2014
The objective of this study was to evaluate the fatty acid profile and qualitative characteristic... more The objective of this study was to evaluate the fatty acid profile and qualitative characteristics of meat from feedlot young bulls fed ground soybean or ground cottonseed, with or without supplementation of vitamin E. A total of 40 Red Norte young bulls, with an initial average age of 20 months, and an initial average BW of 339±15 kg, were allotted in a completely randomized design using a 2×2 factorial arrangement, with two oilseeds, and daily supplementation or not of 2500 IU of vitamin E. The experimental period was for 84 days, which was preceded by an adaptation period of 28 days. The treatments were ground soybean (SB), ground soybean plus vitamin E (SBE), ground cottonseed (CS) and ground cottonseed plus vitamin E (CSE). The percentage of cottonseed and soybean in the diets (dry matter basis) was 24% and 20%, respectively. Diets were isonitrogenous (13% CP) and presented similar amount of ether extract (6.5%). The animals were slaughtered at average live weight of 464±15 kg,...
Lipids in the Diet and the Fatty Acid Profile in Beef: A Review and Recent Patents on the Topic
Recent Patents on Food, Nutrition & Agriculturee, 2012
The objective of this review is to report how the use of lipid sources in diets for ruminants can... more The objective of this review is to report how the use of lipid sources in diets for ruminants can affect the fatty acid profile of beef. In addition, recent patents that can be utilized to alter the fatty acid profile in the meat, or which concern the synthesis of conjugated fatty acids will be reviewed. The industrial production of conjugated linoleic acid (CLA) has already started and the commercial products present isomers cis-9, trans-11; trans-9, cis-11; and trans-10, cis-12. Patents on the biological synthesis of isomer C18:2 cis-9, trans-11 from the linoleic acid have also been published. However, the economic production of CLA in industrial scale is a difficult process. Most of the patents published for CLA production utilize bacteria of the genera Bifidobacterium sp. and Propionibacterium sp. Lipid supplementation, with the objective to improve the fatty acid profile of beef, can be done through the use of patented products, such as genetically modified oilseeds and calcium soaps of fatty acids.
Revista Brasileira de Zootecnia, 2010
Water is a nutrient of extreme importance for animals and must be considered vital in any rearing... more Water is a nutrient of extreme importance for animals and must be considered vital in any rearing phase. The increasing scarcity of this precious natural resource has concerned different segments of society in order to find solutions for rational and sustainable use of this nutrient. Small ruminants, especially sheep and goats, have social and economic importance due to their great ability in adapting to adverse environmental conditions and using water efficiently. Thus, they might be a good alternative to mitigate the climate change effects and to generate foreign exchange and improving life condition in many places of the world. The concept of water productivity for livestock production is relatively new and there are few studies in the world, especially in Brazil. More researches and new technologies for water use in livestock production are indispensable.
Semina: Ciências Agrárias, 2014
Este estudo avaliou as características dos constituintes e não constituintes da carcaça de cordei... more Este estudo avaliou as características dos constituintes e não constituintes da carcaça de cordeiros Santa Inês alimentados com dietas contendo diferentes proporções de farelo de manga (FM) em substituição ao milho. Foram utilizados 24 cordeiros, castrados, com peso corporal inicial médio de 23,3 kg, alojados em baias individuais e alimentados, por 77 dias, com rações isoproteicas, contendo quatro níveis de substituição (0; 33; 66 e 100%) do milho pelo FM. A relação volumoso:concentrado foi de 40:60, com capim elefante (Pennisetum purpureum Schum.) in natura utilizado como volumoso. O delineamento experimental foi inteiramente casualizado, com quatro tratamentos e seis repetições. Considerando os constituintes da carcaça, não foi observada influência (P>0,05) do nível de inclusão do FM, exceto para os cortes serrote e paleta e para o rendimento de paleta. Quanto aos não constituintes da carcaça, observou-se influência (P<0,05) apenas para os rendimentos de fígado e língua. As características quantitativas do lombo não sofreram alterações. O FM pode ser utilizado na alimentação de cordeiros Santa Inês sem prejuízos para as características dos constituintes e não constituintes da carcaça.
Revista Brasileira de Zootecnia, 2005
Quatro novilhos holandeses fistulados no rúmen, com peso médio de 259 kg, foram distribuídos em u... more Quatro novilhos holandeses fistulados no rúmen, com peso médio de 259 kg, foram distribuídos em um quadrado latino 4 x 4 para se avaliar o efeito dos níveis de casca de algodão na dieta de novilhos sobre o consumo e as digestibilidades totais, ruminais e intestinais de matéria seca (MS), matéria orgânica (MO), extrato etéreo (EE), proteína bruta (PB), fibra em detergente neutro corrigida para cinzas e proteína (FDNcp) e carboidratos não-fibrosos corrigidos (CNFcp) e o consumo de nutrientes digestíveis totais (NDT). Também foi avaliada a cinética de degradação ruminal da casca de algodão, da silagem de capim-elefante, do sorgo e do farelo de soja. As dietas experimentais continham na base da matéria seca: 0, 10, 20 e 30% de casca de algodão peletizada, em substituição à silagem de capim-elefante, sendo a dieta total constituída de 60% de volumoso. As digestibilidades foram determinadas utilizando-se a fibra em detergente ácido indigestível como indicador. No ensaio de degradabilidade...
Revista Brasileira de Zootecnia, 2011
The objective of this study was to evaluate the daily intake and total apparent digestibility of ... more The objective of this study was to evaluate the daily intake and total apparent digestibility of dry matter, organic matter, crude protein, gross energy, ether extract, neutral detergent fiber, acid detergent fiber, total and non-fibrous carbohydrates, total digestible nutrients, energy intake and nitrogen balance of silages of six maize varieties with early or super early cycles recommended to Northeast Brazil. Twenty-four male castrated lambs were lodged in metabolic cages. A completely randomized design with six treatments and four replications was used, with means compared by Tukey test at 5%. There were no differences among varieties for any of the evaluated variables regarding intake and apparent digestibility. Concerning the intake of digestible energy, metabolizable energy and the ratio content of digestible and metabolizable energy, significant differences were observed between varieties and BRS Assum Preto showed highest values of metabolizable energy (2.650,8 kcal/day). All of the treatments presented positive nitrogen balance and did not differ among themselves. The varieties asessed can be an additional option to the semiarid regions in Brazil.
Carcass and non-carcass component yields of crossbred Boer and Brazilian semiarid indigenous goats subjected to different feeding levels
Tropical Animal Health and Production, 2014
The effect of different feeding levels (ad libitum, 25 and 50 % restriction) and genotypes (½ Boe... more The effect of different feeding levels (ad libitum, 25 and 50 % restriction) and genotypes (½ Boer × ½ nondescript breed goats, Canindé, and Moxotó) on carcass quantitative characteristics and non-carcass components (NCC) were evaluated. Forty-five intact male goats were distributed in a 3 × 3 factorial design with five replicates. There was no effect of genotype on carcass weights and yields and retail cuts weights and yields (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 0.05). Compared to Moxotó, ½ Boer presented better carcass conformation and higher weights (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) and yields of viscera from gastrointestinal tract (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.05), and compared to the other genotypes (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01), ½ Boer presented larger carcass compactness. Carcass weights and yields, retail cuts weights and NCC, and soft tissues yields were higher (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01) in goats fed ad libitum. The two restriction levels did not differ (P…
Tropical Animal Health and Production, 2012
This experiment was conducted to evaluate the effect of different levels of substitution (0, 33.3... more This experiment was conducted to evaluate the effect of different levels of substitution (0, 33.3, 66.7, and 100 %) of elephant grass by hay of mango tree pruning (HMTP) on intake and digestibility in cattle and on the in vitro gas production. Moreover, the effect of tannin in HMTP on the gas production and in vitro degradability of the dry matter was evaluated, using polyethylene glycol (PEG). The intake and digestibility were evaluated in a double 4×4 square Latin design, using eight Holstein intact bulls. To evaluate the gas production and degradability, in vitro semi-automated gas production technique was used. The substitution of elephant grass by HMTP decreased the intake (P<0.05) and the digestibility (P<0.05) of the nutrients and also the gas production (P<0.05). Furthermore, the utilization of PEG as a tannin-complexing agent increased the gas production and degradability of the HMTP (P<0.05). It was concluded that the high cell wall lignification and the presence of tannin limit the use of HMTP as the only source of roughage in cattle diets.
Revista Brasileira de Zootecnia, 2010
Objetivou-se determinar as exigências proteicas de bovinos anelorados, em pastagem com Brachiaria... more Objetivou-se determinar as exigências proteicas de bovinos anelorados, em pastagem com Brachiaria decumbens suplementada com concentrado. Foram utilizados 28 novilhos zebuínos não-castrados com média de 7 meses de idade e 180 kg. Foram abatidos oitos animais-referência para determinação da composição corporal inicial. Os 20 animais restantes foram divididos em cinco lotes de quatro animais, em delineamento inteiramente ao acaso, de modo que cada lote recebeu um dos cinco planos nutricionais: mantença; mistura mineral; e suplementação nos níveis de 0,75; 1,50 e 2,25 kg/animal/dia. A meia-carcaça direita de todos os animais foi dissecada em músculo, gordura e ossos e todos os constituintes do corpo foram pesados para determinação do peso de corpo vazio e da composição corporal. De posse desses dados, procedeu-se ao cálculo das exigências líquidas para ganho de peso em diversas faixas de peso corporal dos animais. Os conteúdos de proteína retidos no corpo dos animais foram regredidos e...
Meat Science, 2014
This study evaluated the effect of feed restriction and goat genotype on meat quality. Three geno... more This study evaluated the effect of feed restriction and goat genotype on meat quality. Three genotypes (Brazilian native breed Canindé; Brazilian native breed Moxotó; and F1 Boer crossbred animals obtained by crossing Boer bucks with local breed does) and three different feeding regimens (ad libitum fed, AL; restricted fed at 75% of the ad libitum, R.75; or restricted fed at 50% of the average ad libitum intake, R.50) were used. There was no difference (P N 0.05) in chemical composition, total and soluble collagen, and shear force of the Longissimus lumborum muscle among genotypes. However, AL had greater amounts of soluble collagen and crude protein in the muscle (P b 0.05) than R.75. No difference (P N 0.05) was observed for the myofibrillar fragmentation index. The goat genotype presented few differences in their fatty acid profiles. However, goats fed ad libitum had a more favorable fatty acid profile for human health with greater concentrations of oleic acid, unsaturated fatty acids, and conjugated linoleic acid.
Livestock Science, 2009
A comparative slaughter trial was conducted to assess the net requirements for gain of Ca, P, Na,... more A comparative slaughter trial was conducted to assess the net requirements for gain of Ca, P, Na, K and Mg of bulls, steers and heifers of Nellore and Red Angus crossbreds. Twenty seven F1 Nellore and Red Angus crossbred calves (9 steers, 9 bulls, and 9 heifers), averaging 274 kg BW, were used. At the beginning of the trial, three animals from each gender were slaughtered to determine the initial body composition. The remaining 18 animals (3 animals of each gender) were randomly assigned to two treatments: fed 0.75 or 1.5% of BW of concentrate. The diets were based on corn silage and were isonitrogenous (2% N, DM). After three growing periods of 28 d, all animals were slaughtered. The cleaned gastrointestinal tract, organs, carcass, head, hide, tail, feet, and tissues were weighed to determine the empty BW (EBW). These parts were ground separately and subsampled for chemical analyses. The log of the contents of each mineral in the empty body was regressed on the log of the EBW to estimate the net requirement for each mineral per kg of empty body gain (EBG). There were no differences (P N 0.05) in the net requirements for growth of all macrominerals among genders. The equations of the pooled data of the net requirements for growth (g/kg EBG) were: 332.6 × EBW − 0.6367 for Ca, 112.1 × EBW − 0.5615 for P, 10.85 × EBW − 0.3992 for Na, 4.01 × EBW − 0.153 for K, and 3.589 × EBW − 0.462 for Mg. Our findings indicated that retained Ca and retained P were poorly related to the retained protein.
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Papers by Mario Chizzotti