Effect of different systems for the control of environmental temperature on the performance of sows and their litters

Background: In tropical and subtropical regions, temperature values above thermoneutrality for pigs are often experienced and lactating sows maintained outside the thermal comfort zone might have their performance compromised. The use of ventilation or evaporative cooling to maintain animal thermoregulation might be alternatives to minimise animal production losses. The objective of this study was to evaluate the infl uence of three different systems for the control of environmental temperature on the productivity of sows and their litters. Materials, Methods & Results: Three systems of environmental temperature control were evaluated: air-conditioned: AC (n = 79), with farrowing facility temperature controlled by a system of evaporative cooling pads combined with negative pressure ventilation; snout cooler: SC (n = 82), with a cold air outlet directed toward sows, combined with management of curtains; and management of curtains: MC (n = 83). Piglet weight was recorded at cross-fostering, and at 14 and 20 days of age. Temperature (TEMP) and relative humidity (RH) were measured daily at fi ve time points (8:00, 10:00, 12:00, 14:00 and 16:00 h). The variables concerning the sows were analysed with the MIXED procedure of SAS, including the fi xed effect of system and random effects of period and period × system interaction. The weight of piglets, TEMP and RH inside the farrowing facility were analysed as repeated measures using the MIXED procedure. Means were compared with the Tukey-Kramer test. The weight of sows at farrowing, the number of cross-fostered piglets and weight of piglets at cross-fostering were similar among the systems (P > 0.10), with overall means of 241.2 kg, 11.4 piglets and 1.4 kg, respectively.In the AC system, TEMP (23.1ºC) was on average lower (P 0.10) among AC, SC and MC systems regarding sow weight loss during lactation (3.3% vs. 5.0% vs. 4.0%) and weaning-to-estrus interval (4.5 d vs. 5.0 d vs. 4.5 d). The number of weaned piglets was similar among the systems (P > 0.10) with an overall mean of 10.8 weaned piglets. The weight of piglets at weaning tended to be lower (P = 0.083) in the MC than the SC system (5,977 g vs. 6,209 g), whereas piglets of the AC system had an intermediate weight (6,152 g). Discussion: The temperature in SC and MC systems was above the upper critical temperature for sows, mainly between 12:00 and 16:00, which could explain the lower feed intake of sows in the MC system. The higher feed intake of SC sows compared to MC sows is probably related to the microenvironment created by the fresh air over the heads of SC sows improving their thermoregulation and comfort, and preventing a reduction in feed intake. The AC system was the most effi cient in reducing the temperature in the farrowing facility. However, the higher feed intake of AC sows compared to that of MC sows did not result in differences in piglet weight. As the temperature in the AC system was close to the lower critical temperature for the piglets, heating provided to piglets was probably insuffi cient and they required an extra energetic demand for heat production to maintain their body temperature. The higher weight of SC piglets is probably explained by the higher feed intake of sows and by the fact that temperature in the farrowing facility did not decrease as in the AC system

EVOLUÇÃO DA ÁREA DE GESTÃO DE PESSOAS EM UMA INSTITUIÇÃO DE ENSINO FEDERAL: DO OPERACIONAL AO ESTRATÉGICO

A área de gestão de pessoas passou por profundas transformações nas últimas décadas, acompanhando as mudanças sociais vividas tanto na esfera privada como no âmbito público. Estudos sobre a evolução dessa área são importantes para se compreender como esse processo ocorreu e como contribuiu no desenvolvimento das organizações. Na esfera pública, a área procurou acompanhar essas mudanças, passando do nível operacional para o nível estratégico nas organizações. Nesse contexto, este estudo objetivou analisar a área de gestão de pessoas de uma Instituição Federal de Ensino, no período de 1988 a 2014, evidenciando as mudanças de atribuições ocorridas na Pró-Reitoria de Gestão de Pessoas. Trata-se de uma pesquisa documental e de entrevistas semiestruturadas com servidores que ocuparam a função de gestor de pessoas no período estudado. Os resultados apresentados demonstraram a evolução do tema na Instituição, evidenciada, principalmente, pelas mudanças de estrutura e nomenclatura, ampliação das atribuições, e pelos depoimentos dos ex-gestores que atuaram na área

Thermal Stress Indices in Young Nellore Bulls Raised in Tropical Environments

Background: Thermal stress indices are important in predicting and choosing means for mitigating heat stress and defining critical environmental conditions for animal welfare and performance. The aim of this study was to determine the association between 16 thermal stress indices and thermophysiological variables in young Nellore bulls raised in a tropical pasture to determine the most effective parameter of heat stress to assist in the management of the thermal environment and animal welfare.Materials, Methods & Results: Seventy-eight young Nellore bulls (Bos taurus indicus), with a mean age of 10.5 months and mean body weight of 242.09 ± 32.17 kg at first collection, and 17.92 months and body weight 335.80 ± 39.02 kg at last collection, were used. During the experimental period, rectal temperature (RT) and surface temperature at the forehead, scapula, and groin, from which the average surface temperature (AST) was calculated, were measured. The difference between the AST and air temperature (i.e., AST – AT) and between the RT and AST (i.e., RT – AST) defined the thermal gradient. For the evaluation of thermal environment, the dry bulb, wet bulb, and globe temperatures, and wind speed were measured. Relative humidity, mean radiant temperature, solar radiation, temperature humidity index (THI), black global temperature humidity index (BGHI), equivalent temperature index (ETI), environmental stress index (ESI), respiratory rate predictor (PRR), heat load index (HLI), comprehensive climate index (CCI), and index of thermal stress for cows (ITSC) were calculated. The average and maximum air temperatures were above thermal comfort levels, while the average relative humidity was within the ideal limit for cattle. The average globe temperature was higher than the air temperature. Solar radiation presented very high values and wind speeds were very low. RT indicated normothermia in the cattle, and AST and thermal gradient (i.e., AST – AT) indicated thermal comfort. The 16 thermal stress indices demonstrated a significant positive and moderate correlation with AST, but were not significantly correlated with RT.Discussion: The average (28.14°C) and maximum (31.90°C) air temperatures indicated discomfort, since the ideal temperature for cattle is ≤ 27°C. The high thermal load of this region can contribute to poor animal welfare, thus requiring the provision of natural or artificial shade for pasture farming. The cattle in this study were in thermal equilibrium given that they maintained RT within the normal range, and the maximum limit was higher. If RT is maintained within physiological limits, the mechanisms of thermoregulation are able to eliminate excess heat (i.e., thermolysis is equivalent to thermogenesis). The AST was 5.4°C below the RT. It is important to note that deep body temperature (i.e., RT) is more stable than the surface body temperature, which is influenced by ambient temperature. Considering that there was no correlation between thermal stress indices and RT, and that the cattle were able to maintain RT within physiological limits, the Nellore bulls in this study were adapted to the environment. The thermal stress indices evaluated in this study adequately reflected heat stress in young Nellore bulls raised in pastures in a tropical environment. Surface temperature was the physiological parameter that responded most significantly to environmental conditions

Hormônios tireoideanos, qualidade de carcaça e de carne e desempenho produtivo de suínos em crescimento e terminação

The objective of this study was to compare serum concentrations of the hormones triiodothyronine (T3) and thyroxine (T4) in pigs on commercial line beginning and end of growing-finishing phase, correlating them with productive performance, carcass and meat quality. Blood samples were collected from 48 animals at the beginning and end of growing-finishing phase by puncturing the jugular vein, around the same time (08:00 to 10:00). Measurements of serum thyroid hormones were made by enzyme-immunoassay for the quantitative determination of serum concentrations of T3 and T4 in pigs, multichannel analyzer in automatic Chemewell®, using the kit Interkit (Bio check, Inc.). The temperature and relative humidity were measured during the experimental period and the black globe humidity index (BGHI) was calculated to characterize the environment. The following characteristics of productive performance, carcass quality and meat were measured: Initial body weight (IBW), final body weight (FBW), average body weight gain (BWG), backfat thickness at first rib (BTFR), backfat thickness at last rib (BTLR), backfat thickness at the last lumbar (BTLL), carcass length (CL), length of small intestine (SI), lean meat percentage (LM%), pH at 45 minutes (pH45min), pH at 24 hours (pH24h), temperature at 1 minute (T1min), temperature at 24 hours (T24h). The values of temperature, BGHI and relative humidity were hight, characterizing the stressful environment. The T4 and T3 values decreased with increasing age of pigs. It was verified that final T3 negatively and moderately correlated with FBW and BWG, as final T4 with IBW (p<0.05). Initial and final thyroxine negatively and moderately correlated with pH45min and pH24h, respectively (p<0.05). The FBW positively and moderately correlated with BTFR, BTLR, BTLL, CL, SL, but negatively and moderately with LM% (p<0.05). Thus, values of T3 and T4 in pigs early in the growing-finishing phase are larger than in termination. These hormones influence the initial and final weight, BTLL, pH45min and pH24h of growing-finishing pigs.Mestre em Ciências VeterináriasObjetivou-se neste estudo comparar as concentrações séricas de Triiodotironina (T3) e Tiroxina (T4) em suínos de linhagens comerciais no início e término da fase de crescimento-terminação, correlacionando-os com o desempenho produtivo, qualidade de carcaça e de carne. As amostras sanguineas de 48 animais foram coletadas no início e no final da fase de crescimento-terminação por punção da veia jugular externa, sempre no mesmo horário (08:00h as 10:00h). As determinações séricas dos hormônios tireoideanos foram feitas por Enzimaimunoensaio para determinação quantitativa das concentrações séricas de T3 e T4 em suínos, em analisador automático multicanal Chemwell®, utilizando kit da interkit (Bio check, Inc.). A temperatura e umidade do ar foram determinadas durante o período experimental e o índice de temperatura de globo e umidade (ITGU) foi calculado para caracterizar o ambiente. As seguintes características de desempenho produtivo, qualidade de carcaça e de carne foram mensuradas: Peso inicial (PI), peso final (PF), ganho de peso médio diário (GPMD), espessura de toucinho na primeira costela (ETPC), espessura de toucinho na última costela (ETUC), espessura de toucinho na última lombar (ETUL), comprimento de carcaça (CC), comprimento do intestino delgado (ID), porcentagem de carne magra (%CM), pH a 45 minutos (pH45min), pH a 24 horas (pH24h), temperatura a 1 minuto (T1min) e temperatura a 24 horas (T24h). Os valores de temperatura ambiente, ITGU e umidade relativa foram altos, caracterizando ambiente estressante. Os valores de T4 e T3 decresceram com o aumento da idade dos suínos. Verificou-se que T3 final correlacionou negativamente e moderadamente com PF e GPMD, já T4 final com PI (p<0,05). No final da terminação, T3 correlacionou negativamente, porém baixa, com a ETUL (p<0,05). A tiroxina inicial e final correlacionaram negativamente e de forma moderada com pH45min e pH24h, respectivamente (p<0,05). O PF correlacionou positivamente e moderadamente com ETPC, ETUC, ETUL, ID, CC, porém negativamente e moderadamente com %CM (p<0,05). Assim, valores de T3 e de T4 em suínos no início da fase de crescimento-terminação são maiores que na terminação. Estes hormônios influenciam o peso inicial e final, a espessura de toucinho na última lombar, pH45min e pH24h de suínos em crescimento-terminação

Evaluation of adaptation of nellore breed cattle to the tropical environment

The first study aimed to determine among 16 thermal indexes, which are more suitable to identify the effects of heat stress in Nellore bulls bred in a tropical environment. 78 young Nellore bulls (Bos taurus indicus) were used, participating in the V Individual Performance Test of Nellore Bulls, UFU. During the test, the rectal temperature (RT) and the surface temperature on the forehead, scapula and groin were measured in the animals, and then the average surface temperature (AST) was calculated. It was also calculated the difference between the average surface temperature and the air temperature (AST-AT) and the difference between the rectal temperature and the average surface temperature (RT-AST), constituting the thermal gradients. In the thermal environment, dry bulb, wet bulb and black globe temperatures, wind speed, relative humidity and partial vapor pressure were evaluated. Then the average radiant temperature, solar radiation and the Black Globe and Humidity Index (BGHI), Equivalent Temperature Index (ETI), Environmental Stress Index (ESI), Respiratory Rate Predictor (PRR), Thermal Load Index (TLI), Comprehensive Climate Index (CCI), Index Thermal Stress for cows (ITSC) and nine Temperature and Humidity Indexes (THI). The sixteen heat stress indices showed a significant, positive and moderate correlation with the average surface temperature, and not significant with the rectal temperature. When considering that there was no correlation between the thermal stress indexes and the rectal temperature, and even considering that the cattle were able to maintain their rectal temperature within the physiological limits, the Nellore bulls in this study proved to be adapted to the environment. The second study verified the effect of thermophysiological variables at the time of artificial insemination on the pregnancy probability of Nellore bovine females. A total of 816 inseminations of Nellore bovine females were followed, submitted to a fixed-time artificial insemination protocol (FTAI), for five years. At the time of artificial insemination, respiratory rate, rectal and surface temperatures, as well as dry bulb, wet bulb, globe temperature and wind speed temperatures were measured. The Temperature-Humidity Index (THI), Equivalent Temperature Index (ETI), Thermal Load Index (TLI) and solar radiation were calculated. The surface temperature was measured in the forehead (TF) and scapula (TS), obtaining the mean body surface temperature (STM). The difference between the temperature of the mean surface temperature and dry bulb (STM-TDB) and the difference between rectal temperature and the mean surface temperature (RT–STM) was also calculated, constituting the thermal gradients. The pregnancy diagnosis was made on the 28th day after insemination. The number of pregnant or non-pregnant bovine females did not differ between the groups of rectal temperature (RT ≤ 38.7) and (RT> 38.7 ºC). TF and TS showed a significant, positive and high correlation with STM. Factor 1 explained 51.05% of the data variation and the variables with the greatest influence on the composition of this factor are THIBerman, THIThom, TDB, STM, TG, ETI, TF, TLI, PV and TS. TF and STM showed significant, positive and moderate correlations with TDB, PV, TG, THI, TLI and ETI. The probability of pregnancy was not influenced when the animals were divided into groups by the rectal temperature (RT ≤38.7 ºC and RT> 38.7 ºC). In the Cerrado biome, the rectal temperature and the thermal environment in spring and summer, at the time of insemination of Nellore bovine females submitted to FTAI protocol do not influence the probability of pregnancy.UFU - Universidade Federal de UberlândiaTese (Doutorado)O primeiro estudo teve como objetivo determinar dentre 16 índices térmicos quais são mais indicados para identificar os efeitos do estresse por calor em touros da raça Nelore criados em ambiente tropical. Foram utilizados 78 touros jovens da raça Nelore (Bos taurus indicus), participantes da V Prova de Desempenho Individual de Touros Nelore, UFU. Durante a prova foram mensuradas nos animais a temperatura retal (TR) e a temperatura de superfície na fronte, na escápula e na virilha, e em seguida calculada a temperatura de superfície média (TSM). Calculou-se ainda, a diferença entre a temperatura de superfície média e a do ar (TSM-TA) e a diferença entre a temperatura retal e a de superfície média (TR-TSM), constituindo os gradientes térmicos. No ambiente térmico foram mensuradas as temperaturas de bulbo seco, de bulbo úmido e de globo negro, velocidade do vento, umidade relativa e a pressão parcial de vapor. Em seguida calculou-se a temperatura radiante média, a radiação solar e o Índice de Globo Negro e Umidade (IGNU), Índice de Temperatura Equivalente (ITE), Índice de Estresse Ambiental (IEA), Índice de Frequência Respiratória (IFR), Índice de Carga Térmica, Índice Climático Compreensivo, Índice de Estresse Térmico para vacas (IETV) e nove Índices de Temperatura e Umidade (ITU). Os dezesseis índices de estresse térmico apresentaram correlação significativa, positiva e moderada com a temperatura superficial média, e não significativa com a temperatura retal. Ao considerar que não houve correlação entre os índices de estresse térmico com a temperatura retal, e ainda considerando que os bovinos foram capazes de manter sua temperatura retal dentro dos limites fisiológicos, os touros Nelore neste estudo mostraram-se adaptados ao ambiente. O segundo estudo verificou o efeito de variáveis termofisiológicas no momento da inseminação artificial sobre a probabilidade de prenhez de fêmeas bovinas Nelore. Foram acompanhados um total de 816 inseminações de fêmeas bovinas da raça Nelore, submetidas a protocolo de inseminação artificial em tempo fixo (IATF), durante cinco anos. No momento da inseminação artificial foram mensuradas a frequência respiratória e as temperaturas retal e superficial, assim como as temperaturas de bulbo seco, bulbo úmido, de globotermômetro e a velocidade do vento. Calculou-se o Índice de Temperatura e Umidade (ITU), o Índice de Temperatura Equivalente (ITE), Índice de Carga Térmica (ICT) e a radiação solar. A temperatura superficial foi medida na fronte e na escápula obtendo-se a temperatura da superfície corporal média (TSM). Calculou-se, ainda, a diferença entre a temperatura da superfície corporal média e de bulbo seco (TSM-TBS) e a diferença entre temperaturas retal e da superfície corporal média (TR–TSM), constituindo os gradientes térmicos. O diagnóstico de gestação foi realizado no 28º dia pós inseminação. O número de fêmeas bovinas prenhas ou não prenhas não diferiu entre os grupos de temperatura retal G1 (TR ≤ 38,7) e G2 (TR > 38,7 ºC). A TFronte e da TEscápula apresentaram correlação significativa, positiva e alta com a TSM. O fator 1 explicou 51,05% da variação dos dados e as variáveis de maior influência na composição desse fator são ITUBerman, ITU Thom, TBS, TSM, TG, ITE, TFronte, ICT, PP e TEscápula. A TFronte e a TSM apresentaram correlação significativa, positiva e moderada com TBS, PP, TG, ITU, ICT e ITE. O ambiente térmico não representou um desafio aos animais deste estudo. A probabilidade de prenhez não foi influenciada quando dividiu os animais em grupos pela temperatura retal (TR≤38,7 ºC e TR>38,7 ºC). No bioma cerrado, a temperatura retal e o ambiente térmico na primavera e no verão, no momento da inseminação de fêmeas bovinas da raça Nelore submetidas a protocolo de IATF, não influenciam a probabilidade de prenhez.2022-02-2

MÊS DE COLETA DE SANGUE, ORDEM E ESTÁDIO DE LACTAÇÃO E HORMÔNIOS TIREOIDIANOS EM VACAS GUZERÁ

Thyroid hormones are important metabolic modulators, influence the growth and development of the mammary gland and participate in the regulation of milk production. The objective was to investigate the effects of month of blood collection, parity and stage of lactation on thyroxine (T4) and 3, 5, 3' triiodothyronine (T3) concentration in 31 Guzerat cows, in Uberlândia, MG, Brazil. The hormonal dosages were made from blood samples collected monthly, during eleven months. Cows in first third lactation had T4 concentration lower than the non-lactating and cows in middle and final thirds of lactation. The month of blood collection influenced the T4 concentration; the highest concentration was detected in April and lowest in July. In animals at the 1st to 6th parity, T3 concentration did not vary according to the stage of lactation, while at the 7th and 8th parity, the T3 concentration were higher at final third of lactation, and lower at initial third of lactation and in non-lactating cows. Nonlactating cows and cows at the initial and middle thirds of lactation presented the highest T3 concentration in March. Non-lactating cows and cows at the initial third of lactation had lower T3 concentration in January and April to December. Cows in middle thirds lactation had lower T3 values in June, October and December. The lowest concentration of T4 occurs in Guzerat cows, in the first third of lactation, which reflects the great demand of the mammary gland. The order of lactation did not influence the values of T4 and T3. The month of collection influence the values of T4 and T3 for the month of collection is dependent on the stage of lactation

Níveis de hormônios tireoideanos circulantes, desempenho e qualidade de carcaça e carne de suínos em crescimento e terminação Levels of circulating thyroid hormones, performance and carcass and meat quality of growing-finishing swine

Objetivou-se neste estudo comparar as concentrações séricas de triiodotironina (T3) e tiroxina (T4) em suínos de linhagem comercial no início e término da fase de crescimento-terminação, correlacionando-os com o desempenho produtivo, características de qualidade de carcaça e da carne. As amostras sanguíneas de 48 animais foram coletadas no início e no final da fase de crescimento-terminação por punção da veia jugular externa, sempre no mesmo horário (8-10h). As determinações séricas dos hormônios tireoideanos foram feitas por enzimaimunoensaio. Foram feitas avaliações de desempenho e de qualidade de carcaça e de carne. No início e final do alojamento, as concentrações séricas de T3 foram de 1,85 e 1,32nmol L-1, respectivamente, e para T4 de 100,33 e 86,53nmol L-1, respectivamente. Houve correlação negativa e baixa entre T3 final e ganho de peso médio diário, peso final e espessura de toucinho. T4 inicial correlacionou-se negativamente e moderadamente com peso inicial. Os valores de T3 e de T4 em suínos no início da fase de crescimento-terminação são maiores que na terminação. Os hormônios tireoideanos estão associados com o peso inicial e final, espessura de toucinho na última lombar, pH45min e pH24h de suínos em crescimento-terminação.The objective of this study was to compare serum concentrations of the hormones triiodothyronine (T3) and thyroxine (T4) in pigs on commercial line beginning and end of growing-finishing phase, correlating them with productive performance and quality characteristics of carcass and meat. Blood samples were collected from 48 animals at the beginning and end of growing-finishing phase by puncturing the jugular vein, around the same time (08:00 to 10:00a.m.). Measurements of serum thyroid hormones were made by enzyme-immunoassay. It was evaluated the performance and quality of carcass and meat. At the beginning and end of the housing, serum T3 concentrations were 1.85 and 1.32nmol L-1, respectively, and T4 of 100.33 and 86.53nmol L-1, respectively. There was negative correlation between T3 and low-end and average daily weight gain, final weight and backfat thickness. Inicial T4 was moderately and moderately negatively correlated with initial weight. The values of T3 and T4 in pigs early in the growing-finishing phase are larger than in termination. The thyroid hormones are associated with the initial and final weight, backfat thickness at the last lumbar, pH45min and pH24h of growing-finishing pigs

Effect of different systems for the control of environmental temperature on the performance of sows and their litters

Background: In tropical and subtropical regions, temperature values above thermoneutrality for pigs are often experienced and lactating sows maintained outside the thermal comfort zone might have their performance compromised. The use of ventilation or evaporative cooling to maintain animal thermoregulation might be alternatives to minimise animal production losses. The objective of this study was to evaluate the infl uence of three different systems for the control of environmental temperature on the productivity of sows and their litters. Materials, Methods & Results: Three systems of environmental temperature control were evaluated: air-conditioned: AC (n = 79), with farrowing facility temperature controlled by a system of evaporative cooling pads combined with negative pressure ventilation; snout cooler: SC (n = 82), with a cold air outlet directed toward sows, combined with management of curtains; and management of curtains: MC (n = 83). Piglet weight was recorded at cross-fostering, and at 14 and 20 days of age. Temperature (TEMP) and relative humidity (RH) were measured daily at fi ve time points (8:00, 10:00, 12:00, 14:00 and 16:00 h). The variables concerning the sows were analysed with the MIXED procedure of SAS, including the fi xed effect of system and random effects of period and period × system interaction. The weight of piglets, TEMP and RH inside the farrowing facility were analysed as repeated measures using the MIXED procedure. Means were compared with the Tukey-Kramer test. The weight of sows at farrowing, the number of cross-fostered piglets and weight of piglets at cross-fostering were similar among the systems (P > 0.10), with overall means of 241.2 kg, 11.4 piglets and 1.4 kg, respectively.In the AC system, TEMP (23.1ºC) was on average lower (P 0.10) among AC, SC and MC systems regarding sow weight loss during lactation (3.3% vs. 5.0% vs. 4.0%) and weaning-to-estrus interval (4.5 d vs. 5.0 d vs. 4.5 d). The number of weaned piglets was similar among the systems (P > 0.10) with an overall mean of 10.8 weaned piglets. The weight of piglets at weaning tended to be lower (P = 0.083) in the MC than the SC system (5,977 g vs. 6,209 g), whereas piglets of the AC system had an intermediate weight (6,152 g). Discussion: The temperature in SC and MC systems was above the upper critical temperature for sows, mainly between 12:00 and 16:00, which could explain the lower feed intake of sows in the MC system. The higher feed intake of SC sows compared to MC sows is probably related to the microenvironment created by the fresh air over the heads of SC sows improving their thermoregulation and comfort, and preventing a reduction in feed intake. The AC system was the most effi cient in reducing the temperature in the farrowing facility. However, the higher feed intake of AC sows compared to that of MC sows did not result in differences in piglet weight. As the temperature in the AC system was close to the lower critical temperature for the piglets, heating provided to piglets was probably insuffi cient and they required an extra energetic demand for heat production to maintain their body temperature. The higher weight of SC piglets is probably explained by the higher feed intake of sows and by the fact that temperature in the farrowing facility did not decrease as in the AC system

Ingestive behaviour of Nelore bulls fed with a GrowSafe system and its relation to the thermal environment

<p>The demand for food, especially of animal origin, is increasing every year. On the other hand, it is believed that climate changes will have impacts on livestock production, especially in tropical regions. Therefore, the development and improvement of livestock production systems is crucial. Thus, the objective of this study was to relate the ingestive behavior of Nellore cattle reared in confinement and fed with a GrowSafe System with measures of the thermal environment. Fifty Nelore bulls, with an average age of 21 months were distributed into two paddocks. The behavioural categories (resting while standing, resting while lying, ruminating while standing, ruminating while lying, eating at feedbunk and feedbunk intention) and meteorological variables (dry and wet bulb temperatures, wind speed [v] and black globe temperature [Tg] were evaluated. The Temperature and Humidity Index (THI), Equivalent Temperature Index (ETI), Black Globe humidity Index (BGHI) and Heat Load Index (HLI) were calculated. Observations were divided into two periods (morning and afternoon) and the study was divided into the following schedules: 1 = 07 hours to 08 hours; 2 = 08 hours: 30 minutes to 09 hours 30 minutes; 3 = 13 hours: 45 minutes to 14 hours: 45 minutes; 4 = 15 hours: 30 minutes to 16 hours: 30 minutes and 5 = 17 hours: 15 minutes to 18 hours: 15 minutes. Pearson's simple correlation between ingestive behavior and thermal environment measurements was performed. There was a positive and moderate correlation between animals eating at feedbunk and air temperature (Ta). Ruminating while standing showed moderate and negative correlation with Ta and Tg, being moderate and positive with relative humidity (Ur). Ruminating while lying correlated moderately and positively with HLI. There was a moderate and negative correlation between the resting while standing activity and the variables Tg, v, BGHI and HLI, while resting while lying had a moderate and positive correlation with Tg and HLI. It is concluded that the thermal environment can affect the ingestive behavior of confined Nellore bulls fed through a GrowSafe System during winter time at Uberlândia, MG.</p