Dwarf and tall elephant grass silages: intake, nutrient digestibility, nitrogen balance, ruminal fermentation, and ingestive behavior in sheep.

The objective of this study was to evaluate the exclusive supply of dwarf or tall elephant grass silages, harvested at 60 days of growth, without wilting or the use of additives, on intake, apparent digestibility, nitrogen balance, rumen parameters, and ingestive behavior of sheep. Eight castrated male crossbred sheep (57.6 ± 5.25 kg body weight), fistulated in the rumen, were distributed in two 4 × 4 Latin squares with four treatments and eight animals per treatment and four periods. The treatments consisted of four elephant grass genotype silages (Mott, Taiwan A-146 2.37, IRI-381, or Elephant B). There was no effect of silages (P > 0.05) on dry matter, neutral detergent fiber, and total digestible nutrient intake. The dwarf-sized elephant grass silages provided higher crude protein intake (P = 0.047) and N intake (P = 0.047), while the IRI-381 genotype silage provided higher non-fibrous carbohydrate intake compared to Mott (P = 0.042), without differing from Taiwan A-146 2.37 and Elephant B silages. There were no differences (P > 0.05) among the digestibility coefficients of the evaluated silages. It was observed that silages produced with Mott and IRI-381 genotypes caused a slight decrease in ruminal pH (P = 0.013), and the propionic acid concentration was higher in the rumen fluid of the animals fed with Mott silage (P = 0.021). Therefore, dwarf or tall elephant grass silages, produced with cut genotypes at 60 days of growth and without the use of additives or wilting process, can be used in sheep feeding.

Carcass and meat traits of bubaline finished on sugarcane-based diets supplemented with spineless cactus as a replacement for wheat bran.

OBJECTIVE: An experiment was conducted to evaluate the effects of increasing levels of spineless cactus (0%, 33%, 66%, and 100%) used as a substitute for wheat bran in buffalo diets on quantitative and qualitative traits of the meat and carcass. METHODS: Twenty Murrah buffaloes at 18 months of age, with a mean initial weight of 292.9±57.3 kg, were randomly allocated to four treatments with five replicates. The animals were slaughtered after 90 days in the feedlot. The effects of spineless cactus as a replacement for wheat bran in the diet of the buffaloes on the carcass and meat traits, slaughter weight, carcass yield and carcass measurements were studied. RESULTS: Increased spineless cactus levels led to linear reduction in average daily gain, slaughter weight, hot and cold carcass weight, compactness index and in the amount of muscle in the carcass, and there is no difference between the control treatment and the 33% replacing level for these parameters. The quality of the meat was not influenced by the treatments. CONCLUSION: Spineless cactus can replace wheat bran by up to 33% in sugarcane-based diets for buffaloes, without influencing quantitative and qualitative traits of the meat and carcass.

Prediction of carcass composition through measurements in vivo and measurements of the carcass of growing Santa Inês sheep.

In vivo and carcass measurements were evaluated to predict carcass physical and chemical composition and to list the measurements that best fit the prediction of the composition of growing Santa Inês sheep carcasses. Thirty-three animals were used to measure the loin eye area by ultrasound in vivo (LEAu) and in the carcass. We used 39 animals for biometric measurement in vivo and 42 sheep for morphometric measurement in the carcass. For the physical and chemical compositions of carcasses, dissection of the half left carcass was carried out in 42 animals. The data were submitted to Pearson's correlation analysis and t test. Simple and multiple linear regressions were performed using a stepwise procedure. All correlations between in vivo measurements and the physical and chemical compositions of carcasses (in kg) were significant, except for LEAu. Biometric measurements and hot (HCW) and cold (CCW) carcass weights were considered as predictors of the carcasses' physical and chemical compositions. Slaughter body weight (SBW) was the variable that most influenced the equations in the assessment of in vivo measurements and HCW and CCW most influenced the equations for measurements on carcasses. Biometric measurements of Santa Inês sheep can be used together with the SBW to estimate the physical and chemical compositions of carcasses, with emphasis on body compactness index, breast width, wither height, and croup height. The morphometric measurements can be used together with carcass weight to estimate the physical and chemical compositions of carcasses, with emphasis on croup width, carcass compactness index, croup perimeter, external and internal carcass lengths, chest width, and leg length and perimeter. The HCW can be used to predict the physical and chemical composition of carcasses without affecting the accuracy of the prediction model.

Nutritional effects of using cactus cladodes (Opuntia stricta Haw Haw) to replace sorghum silage in sheep diet.

The aim of the present study was to evaluate the effects of replacing the sorghum silage in sheep diet with cactus cladodes [CC - Opuntia stricta (Haw) Haw] on dry matter and its compound intake and digestibility, feeding behavior, and nitrogen balance. The diets consisted of five replacement levels [0, 200, 400, 600, and 800 g/kg on a dry matter (DM) basis] and were formulated to be isonitrogenous [140 g/kg crude protein [CP], considering the ingredients' composition, with a roughage/concentrate ratio of 65:35, on a DM basis. Five uncastrated crossbred sheep, with an average body weight of 52.9 ± 6.0 kg, were assigned to a 5 × 5 Latin square. The trial lasted for 105 days with five consecutive 21-day periods, divided into 14-day adaptation and 7-day sampling periods. Dry matter (DM), organic matter, non-fiber carbohydrate (NFC), total digestible nutrient intake, and DM and NFC digestibility, increased (P ≤ 0.04) with the replacement of sorghum silage by CC. However, the time spent feeding and ruminating decreased, while idle time increased (P ≤ 0.03). Only feeding and rumination efficiency of DM improved (P ≤ 0.01) with the replacement, whereas feeding and rumination efficiency of neutral detergent fiber corrected to ash and protein did not. Nitrogen intake and nitrogen balance were not influenced, and urinary volume increased (P ≤ 0.01) with the addition of CC in the diet. In conclusion, we recommend replacing 80% of the sorghum silage with CC in sheep diets (with 35% concentrate), as CC was found to substantially increase the intake of nutrients, primarily energy.

Sugarcane and cactus cladodes plus urea: a new option for Girolando dairy heifers

This study was performed to identify the ideal amount of concentrate required for a diet based on cactus cladodes, sugarcane, and urea used to feed heifers. Twenty Girolando heifers (160±8.39 kg) were randomly distributed into four experimental treatments with 0, 0.40, 0.80, or 1.20 kg day−1 of concentrate. The basal diet contained [on dry matter (DM) basis] 38.1% sugarcane, 56.5% cactus cladodes [ Opuntia stricta (Haw). Haw.], 0.5% common salt, 1.1% mineral mixture, and 3.8% urea plus ammonium sulfate. The concentrate contained [on DM basis] 87% corn meal and 13% soybean meal. The basal diet and the concentrate were formulated to provide 13% crude protein (CP). The intake of DM (4.34-4.96 kg day−1), organic matter (3.96-4.98 kg day−1), CP (0.57-0.64 kg day−1), non-fibrous carbohydrates (2.20-2.61 kg day−1), and metabolizable energy (10.3-12.4 Mcal day−1) increased linearly with concentrate amount. Final body weight (196-224 kg), total body weight gain (36.9-61.2 kg), and average daily body weight gain (0.51-0.85 kg day−1) increased linearly with concentrate amount. The nitrogen balance was positive and increased linearly (54.8-62.3 g day−1) with concentrate amount. Based on the data, we recommend supplying six-month-old Girolando heifers (160 kg body weight) 1.20 kg concentrate day−1 added to a diet based on sugarcane and cactus cladodes plus urea for better productive and economic performance.(AU)

Ingestive behavior of buffaloes fed increasing levels of concentrate in sugarcane based diets / Comportamento ingestivo de búfalos alimentados com níveis crescentes de concentrado em dietas com cana-de-açúcar

The experiment was conducted to evaluate the ingestive behavior of buffalo fed sugarcane with different levels of concentrate. Twenty four Murrah buffaloes with body weight of 219±23 kg and nine months old were assigned to completely randomized design. Animals were placed in individual pens where they received diets ad libitum, twice a day. The experimental period has divided into 30 d for adaptation and 84 d for observations and samples collection. Four treatments were used: 1) 80% sugarcane (SC) + 20% concentrate (C); 2) 60% SC + 40% C; 3) 40% SC + 60% C; 4) 20% SC + 80% C. The diets were isoproteics and urea/ammonium sulfate was used at 9:1 ratio to correct the protein level of sugarcane. The evaluated variables were time spent feeding (TSF), ruminating (TSR), idle (TSI), dry matter intake (DMI), feeding efficiency of dry matter (FEDM), rumination efficiency of dry matter (REDM), number of meals, duration of meal and duration of breaks between meal. A regression analysis was performed using the MIXED procedure. DMI was positively affected (P0.05) on TSF. However, the TSR and number of meals decreased linearly (P<0.05) as the dietary levels of concentrate increased.TSI, duration of meal and duration of breaks between meals increased linearly (P<0.05). Increasing levels of concentrate up to 80% in sugarcane based diets influence directly the feeding behavior of buffaloes resulting in fewer daily meals and more time in the trough, improving the feeding and rumination efficiencies.

O experimento foi conduzido para avaliar o comportamento ingestivo de búfalos alimentados com cana-de-açúcar e diferentes níveis de concentrado. Vinte e quatro búfalos Murrah com peso corporal de 219 ± 23 kg e nove meses de idade foram distribuídos em delineamento inteiramente casualizado. Os animais foram manejados em baias individuais, onde receberam dietas ad libitum, duas vezes ao dia. O período experimental foi dividido em 30 dias para adaptação e 84 dias para observações e coleta de amostras. Foram utilizados quatro tratamentos: 1) 80% de cana-de-açúcar (SC) + 20% de concentrado (C); 2) 60% SC + 40% C; 3) 40% SC + 60% C; 4) 20% SC + 80% C. As dietas foram isoproteicas e uma mistura de ureia/sulfato de amônio na proporção de 9:1 foi utilizada para corrigir o nível de proteína da cana-de-açúcar. As variáveis avaliadas foram: tempo gasto na alimentação (TSF), ruminação (TSR), ócio (ETI), consumo de matéria seca (DMI), eficiência alimentar em função do consumo de matéria seca (FEDM), eficiência da ruminação em função do consumo de matéria seca (REDM), número de refeições, duração da refeição e duração dos intervalos entre as refeições. Uma análise de regressão foi realizada usando o procedimento MIXED. O DMI foi afetado positivamente (P0,05) no TSF. No entanto, o TSR e o número de refeições diminuíram linearmente (P<0,05) à medida que os níveis alimentares de concentrado aumentaram. A ETI, a duração da refeição e a duração dos intervalos entre as refeições aumentaram linearmente (P<0,05). Níveis crescentes de concentrado em até 80% em dietas à base de cana-de-açúcar influenciam diretamente o comportamento alimentar dos búfalos, resultando em menos refeições diárias e mais tempo no cocho, melhorando a eficiência de alimentação e de ruminação.

Ingestive behavior of buffaloes fed increasing levels of concentrate in sugarcane based diets / Comportamento ingestivo de búfalos alimentados com níveis crescentes de concentrado em dietas com cana-de-açúcar

The experiment was conducted to evaluate the ingestive behavior of buffalo fed sugarcane with different levels of concentrate. Twenty four Murrah buffaloes with body weight of 219±23 kg and nine months old were assigned to completely randomized design. Animals were placed in individual pens where they received diets ad libitum, twice a day. The experimental period has divided into 30 d for adaptation and 84 d for observations and samples collection. Four treatments were used: 1) 80% sugarcane (SC) + 20% concentrate (C); 2) 60% SC + 40% C; 3) 40% SC + 60% C; 4) 20% SC + 80% C. The diets were isoproteics and urea/ammonium sulfate was used at 9:1 ratio to correct the protein level of sugarcane. The evaluated variables were time spent feeding (TSF), ruminating (TSR), idle (TSI), dry matter intake (DMI), feeding efficiency of dry matter (FEDM), rumination efficiency of dry matter (REDM), number of meals, duration of meal and duration of breaks between meal. A regression analysis was performed using the MIXED procedure. DMI was positively affected (P<0.05) by concentrate levels. The treatments had no effect (P>0.05) on TSF. However, the TSR and number of meals decreased linearly (P<0.05) as the dietary levels of concentrate increased.TSI, duration of meal and duration of breaks between meals increased linearly (P<0.05). Increasing levels of concentrate up to 80% in sugarcane based diets influence directly the feeding behavior of buffaloes resulting in fewer daily meals and more time in the trough, improving the feeding and rumination efficiencies.(AU)

O experimento foi conduzido para avaliar o comportamento ingestivo de búfalos alimentados com cana-de-açúcar e diferentes níveis de concentrado. Vinte e quatro búfalos Murrah com peso corporal de 219 ± 23 kg e nove meses de idade foram distribuídos em delineamento inteiramente casualizado. Os animais foram manejados em baias individuais, onde receberam dietas ad libitum, duas vezes ao dia. O período experimental foi dividido em 30 dias para adaptação e 84 dias para observações e coleta de amostras. Foram utilizados quatro tratamentos: 1) 80% de cana-de-açúcar (SC) + 20% de concentrado (C); 2) 60% SC + 40% C; 3) 40% SC + 60% C; 4) 20% SC + 80% C. As dietas foram isoproteicas e uma mistura de ureia/sulfato de amônio na proporção de 9:1 foi utilizada para corrigir o nível de proteína da cana-de-açúcar. As variáveis avaliadas foram: tempo gasto na alimentação (TSF), ruminação (TSR), ócio (ETI), consumo de matéria seca (DMI), eficiência alimentar em função do consumo de matéria seca (FEDM), eficiência da ruminação em função do consumo de matéria seca (REDM), número de refeições, duração da refeição e duração dos intervalos entre as refeições. Uma análise de regressão foi realizada usando o procedimento MIXED. O DMI foi afetado positivamente (P<0,05) pelos níveis de concentrado. Os tratamentos não tiveram efeito (P>0,05) no TSF. No entanto, o TSR e o número de refeições diminuíram linearmente (P<0,05) à medida que os níveis alimentares de concentrado aumentaram. A ETI, a duração da refeição e a duração dos intervalos entre as refeições aumentaram linearmente (P<0,05). Níveis crescentes de concentrado em até 80% em dietas à base de cana-de-açúcar influenciam diretamente o comportamento alimentar dos búfalos, resultando em menos refeições diárias e mais tempo no cocho, melhorando a eficiência de alimentação e de ruminação.(AU)

Can the body composition of crossbred dairy cattle be predicted by equations for beef cattle?

OBJECTIVE: The aim of the study was to evaluate the efficiency of the Hankins and Howe (HH46), Valadares Filho (V06), and Marcondes (M12) equations for predicting the physical and chemical composition of dairy crossbred bulls carcasses, as well as the chemical composition of their empty bodies. METHODS: This study was conducted using 30 dairy crossbred bulls. One group of five animals was slaughtered at the beginning of the experiment, and the remaining were slaughtered 112 days later. Animals were distributed in a completely randomized design into treatments consisting different levels of concentrate (0%, 17%, 34%, 51%, and 68%). The physical and chemical compositions of the cattle were obtained from the right half of the carcass and using samples taken between the 9th and 11th ribs of the left half of the carcass. The estimated and experimentally determined values were compared using the correlation and concordance coefficient, as well as the mean square error of prediction (MSEP) and its components. RESULTS: The HH46 equations were better at estimating the amount of muscle plus fat in the carcass. The amount of bone in the carcasses could not be well estimated by the HH46 and M12 models. The M12, HH46, and V06 equations were worst at estimating the amounts of protein, ether extract, and water in the carcass, respectively. In the empty body, the amounts of protein and water were well estimated by the HH46 equations. Protein, ether extract, and water were accurately estimated by the V06 equations, and ether extract by the M12 equations. CONCLUSION: The physical and chemical composition of dairy crossbred bull carcasses, as well as the chemical composition of their empty bodies, can be predicted using the equations tested here. The amount of bone in these carcasses could not be accurately predicted.

Energy and protein requirements of crossbred cattle in feedlot / Exigências energéticas e proteicas de bovinos mestiços em confinamento

The objective of this study is to predict the energy and protein requirements of crossbred dairy cattle in feedlot. The study was conducted at the Unidade Acadêmica de Serra Talhada, Universidade Federal Rural de Pernambuco, Brazil with 30 bulls with a body weight of 339.1 ± 35.4 kg. Five animals were slaughtered at the end of the adaptation period to serve as the reference group; the remainder of the animals was slaughtered after 112 days. The latter group was randomly allocated to receive five treatments: 0, 17, 34, 51 and 68% of concentrate in the feed using a completely randomized design. The dietary intake of the animals that were not given concentrate was restricted to 1.5% of their body weight; these animals composed the group fed for maintenance. The body composition and empty body weight (EBW) were estimated by means of the comparative slaughter method and full dissection of a half-carcass. The results showed that for crossbred dairy bulls in confinement, the net and metabolizable energy requirements were 86.49 and 138 kcal EBW-0.75 day-1, respectively, and the efficiency of use of metabolizable energy for maintenance and gain were 62.67% and 31.67%, respectively. The net energy (NEg) and net protein (NPg) requirements for gain can be estimated using the following equations, respectively: NEg= 0.0392*EBW0.75*EBWG1.0529 and NPg= 242.34 x EBWG - 23.09 x RE. The efficiency of use of metabolizable protein for gain was 25.8%, and the protein requirement for maintenance was 2.96 g EBW-0.75 day-1. The rumen degradable protein can supply 62.44% of the crude protein requirements of feedlot dairy crossbred bulls with a body weight of 450 kg while gaining 1 kg day-1.(AU)

Com o objetivo de predizer as exigências energéticas e proteicas de bovinos mestiços leiteiros em confinamento, este trabalho foi conduzido na Unidade Acadêmica de Serra Talhada da Universidade Federal Rural de Pernambuco. Foram utilizados 30 machos não castrados, com peso corporal inicial de 339,1 ± 35,4 kg. Cinco animais foram abatidos após período de adaptação, compondo o grupo referência, e o restante foi abatido após 112 dias. Os remanescentes foram distribuídos aleatoriamente em cinco tratamentos: 0, 17, 34, 51 e 68% de concentrado na ração, em delineamento inteiramente casualizado. Os bovinos que não receberam concentrado tiveram seu consumo restrito para 1,5% do seu peso corporal, compondo o grupo de animais alimentados ao nível de mantença. A composição corporal e o peso de corpo vazio (PCVZ) foram obtidos pela técnica do abate comparativo e dissecação completa da meia carcaça. Para bovinos mestiços leiteiros, não castrados, confinados, as exigências líquida e metabolizável de energia para mantença foram de 86,49 e 138 kcal PCVZ-0,75 dia-1, respectivamente, enquanto que as eficiências de utilização da energia metabolizável (EUEM) para mantença e ganho foram de 62,67 e 31,67%, respectivamente. Já as exigências líquidas de energia (ELg) e proteina (PLg) para ganho, podem ser estimadas a partir das seguintes equações: ELg = 0,0392*PCVZ0,75*GPCVZ1,0529e PLg = 242,34 × GPCVZ - 23,09 × ER, respectivamente. A eficiência do uso da proteína metabolizável para ganho foi de 25,8% enquanto que as exigências de proteína para mantença foram 2,96 g PCVZ-0,75 dia-1. A proteína degradável no rúmen pode suprir 62,44% das exigências em proteína bruta de bovinos mestiços leiteiros, machos não castrados, em confinamento, com peso corporal de 450 kg e ganho de 1 kg dia-1.(AU)

Energy and protein requirements of crossbred cattle in feedlot / Exigências energéticas e proteicas de bovinos mestiços em confinamento

The objective of this study is to predict the energy and protein requirements of crossbred dairy cattle in feedlot. The study was conducted at the Unidade Acadêmica de Serra Talhada, Universidade Federal Rural de Pernambuco, Brazil with 30 bulls with a body weight of 339.1 ± 35.4 kg. Five animals were slaughtered at the end of the adaptation period to serve as the reference group; the remainder of the animals was slaughtered after 112 days. The latter group was randomly allocated to receive five treatments: 0, 17, 34, 51 and 68% of concentrate in the feed using a completely randomized design. The dietary intake of the animals that were not given concentrate was restricted to 1.5% of their body weight; these animals composed the group fed for maintenance. The body composition and empty body weight (EBW) were estimated by means of the comparative slaughter method and full dissection of a half-carcass. The results showed that for crossbred dairy bulls in confinement, the net and metabolizable energy requirements were 86.49 and 138 kcal EBW-0.75 day-1, respectively, and the efficiency of use of metabolizable energy for maintenance and gain were 62.67% and 31.67%, respectively. The net energy (NEg) and net protein (NPg) requirements for gain can be estimated using the following equations, respectively: NEg= 0.0392*EBW0.75*EBWG1.0529 and NPg= 242.34 x EBWG - 23.09 x RE. The efficiency of use of metabolizable protein for gain was 25.8%, and the protein requirement for maintenance was 2.96 g EBW-0.75 day-1. The rumen degradable protein can supply 62.44% of the crude protein requirements of feedlot dairy crossbred bulls with a body weight of 450 kg while gaining 1 kg day-1.

Com o objetivo de predizer as exigências energéticas e proteicas de bovinos mestiços leiteiros em confinamento, este trabalho foi conduzido na Unidade Acadêmica de Serra Talhada da Universidade Federal Rural de Pernambuco. Foram utilizados 30 machos não castrados, com peso corporal inicial de 339,1 ± 35,4 kg. Cinco animais foram abatidos após período de adaptação, compondo o grupo referência, e o restante foi abatido após 112 dias. Os remanescentes foram distribuídos aleatoriamente em cinco tratamentos: 0, 17, 34, 51 e 68% de concentrado na ração, em delineamento inteiramente casualizado. Os bovinos que não receberam concentrado tiveram seu consumo restrito para 1,5% do seu peso corporal, compondo o grupo de animais alimentados ao nível de mantença. A composição corporal e o peso de corpo vazio (PCVZ) foram obtidos pela técnica do abate comparativo e dissecação completa da meia carcaça. Para bovinos mestiços leiteiros, não castrados, confinados, as exigências líquida e metabolizável de energia para mantença foram de 86,49 e 138 kcal PCVZ-0,75 dia-1, respectivamente, enquanto que as eficiências de utilização da energia metabolizável (EUEM) para mantença e ganho foram de 62,67 e 31,67%, respectivamente. Já as exigências líquidas de energia (ELg) e proteina (PLg) para ganho, podem ser estimadas a partir das seguintes equações: ELg = 0,0392*PCVZ0,75*GPCVZ1,0529e PLg = 242,34 × GPCVZ - 23,09 × ER, respectivamente. A eficiência do uso da proteína metabolizável para ganho foi de 25,8% enquanto que as exigências de proteína para mantença foram 2,96 g PCVZ-0,75 dia-1. A proteína degradável no rúmen pode suprir 62,44% das exigências em proteína bruta de bovinos mestiços leiteiros, machos não castrados, em confinamento, com peso corporal de 450 kg e ganho de 1 kg dia-1.

Níveis críticos do Índice de Conforto Térmico para ovinos da raça Santa Inês criados a pasto no agreste do Estado de Pernambuco / Critical levels of the Thermal Comfort Index for Santa Inês sheep under grazing at the agreste region of Pernambuco State

O objetivo deste trabalho foi estimar os valores críticos do Índice de Conforto Térmico (ICT) para ovinos deslanados da raça Santa Inês em condições de pastejo, com base nos parâmetros fisiológicos. O experimento foi conduzido de janeiro a abril na região agreste do Estado de Pernambuco. Os parâmetros temperatura retal (TR) e frequência respiratória (FR) foram avaliados três vezes por semana nos períodos da manhã e da tarde. O ambiente foi monitorado diariamente, por intermédio de uma estação meteorológica instalada ao lado do piquete experimental. As medidas para as análises de regressão foram obtidas de 15 ovinos da raça Santa Inês, sendo cinco de cada cor: branca, castanha e preta. Baseando-se na TR, os valores críticos do ICT estimados para os ovinos brancos, castanhos e pretos foram, respectivamente de 46,3; 45,5 e 44,5. Baseando-se na FR, o valor crítico de ICT foi de 38,0 para os animais das três cores.

The objective of this research was to estimate the critical values of the Thermal Comfort Index (TCI) for Santa Inês sheep under grazing conditions, based on physiological parameters. The experiment was conducted from January to April in the agreste region of Pernambuco State. The rectal temperature (RT) and respiratory rate (RR) were evaluated three times a week in the morning and in the afternoon. The environment was monitored daily, in a meteorological station installed next to the paddock. The measurements for regression analysis were obtained from 15 Santa Inês sheep with five animals for each color: white, chestnut, and black. Based on the RT, the estimated critical values of TCI for white, chestnut, and black sheep were, respectively, 46.3, 45.5 and 44.5. Based on the RR, the estimated critical value of TCI was 38.0 for the animals of all three coat colors.

Níveis críticos do Índice de Conforto Térmico para ovinos da raça Santa Inês criados a pasto no agreste do Estado de Pernambuco / Critical levels of the Thermal Comfort Index for Santa Inês sheep under grazing at the agreste region of Pernambuco State

O objetivo deste trabalho foi estimar os valores críticos do Índice de Conforto Térmico (ICT) para ovinos deslanados da raça Santa Inês em condições de pastejo, com base nos parâmetros fisiológicos. O experimento foi conduzido de janeiro a abril na região agreste do Estado de Pernambuco. Os parâmetros temperatura retal (TR) e frequência respiratória (FR) foram avaliados três vezes por semana nos períodos da manhã e da tarde. O ambiente foi monitorado diariamente, por intermédio de uma estação meteorológica instalada ao lado do piquete experimental. As medidas para as análises de regressão foram obtidas de 15 ovinos da raça Santa Inês, sendo cinco de cada cor: branca, castanha e preta. Baseando-se na TR, os valores críticos do ICT estimados para os ovinos brancos, castanhos e pretos foram, respectivamente de 46,3; 45,5 e 44,5. Baseando-se na FR, o valor crítico de ICT foi de 38,0 para os animais das três cores.(AU)

The objective of this research was to estimate the critical values of the Thermal Comfort Index (TCI) for Santa Inês sheep under grazing conditions, based on physiological parameters. The experiment was conducted from January to April in the agreste region of Pernambuco State. The rectal temperature (RT) and respiratory rate (RR) were evaluated three times a week in the morning and in the afternoon. The environment was monitored daily, in a meteorological station installed next to the paddock. The measurements for regression analysis were obtained from 15 Santa Inês sheep with five animals for each color: white, chestnut, and black. Based on the RT, the estimated critical values of TCI for white, chestnut, and black sheep were, respectively, 46.3, 45.5 and 44.5. Based on the RR, the estimated critical value of TCI was 38.0 for the animals of all three coat colors.(AU)