<b>Adaptive parameters and thermal comfort of postpartum ewes fed on concentrate supplementation in grazing system

Abstract

ABSTRACT. Current analysis evaluated adaptive parameters and thermal comfort of postpartum ewes fed on concentrate supplementation in grazing system. Thirty lactating pluriparous sheep, 16 Santa Inês (SI) and 14 Morada Nova (MN) were used. Physiological parameters such as respiratory rate (RR), heart rate (HR) and rectal temperature (RT) were measured, in that order, with the animals at rest in the morning (6:00-7:00 am) and in the afternoon (1:00-2:00 pm), respectively, every seven days, with 10 samples. A significant effect (p < 0.05) for RR and HR was reported in the strain. Similar behavior was reported for RR between the breeds where MN sheep had high adaptability. Supplementation levels of 0.5 and 1.5% influenced (p < 0.05) RR which was stronger in the sheep that received the highest supplementation level, possibly due to calorie increase in the diet. However, HR and RT parameters did not differ within the breed due to supplementation. HR was higher between the breeds for SI sheep at 0.5%. Results show that concentrated supplementation affected the respiratory rate of ewes in the postpartum period, with higher calorie increment at 1.5% level and superiority for Santa Inês ewes. Greater adaptability of Morada Nova sheep has been indicated when fed on concentrated diet in grazing system.Keywords: environmental factors, heat stress, nutrition, thermoregulation.Parâmetros adaptativos e conforto térmico de ovelhas deslanadas no pós-parto submetidas à suplementação concentrada em sistema de pastejo RESUMO. Objetivou-se avaliar os parâmetros adaptativos e o conforto térmico de ovelhas deslanadas no pós-parto submetidas à suplementação concentrada em sistema de pastejo. Foram utilizadas 30 ovelhas pluríparas em lactação, sendo 16 da raça Santa Inês e 14 da raça Morada Nova. Os parâmetros fisiológicos, frequência cardíaca (FC), frequência respiratória (FR) e temperatura retal (TR) foram aferidos nessa ordem com os animais em repouso nos períodos da manhã e da tarde, de 6:00-7:00 e 13:00-14:00, respectivamente, a cada sete dias, totalizando dez coletas. Houve efeito de turno (p < 0,05) para FR e FC dentro de raça. Comportamento semelhante foi observado para FR entre raças, em que as ovelhas Morada Nova apresentaram maior adaptabilidade. Os níveis de suplementação de 0,5 e 1,5% exerceram influência (p < 0,05) sobre a FR com superioridade para as ovelhas que receberam maior nível de suplementação, possivelmente pelo incremento calórico na dieta. No entanto, os parâmetros FC e TR não diferiram dentro de raça em função da suplementação, sendo que entre raças a FC foi superior para ovelhas SI a 0,5%. Conclui-se que a suplementação concentrada exerceu influência sobre frequência respiratória das ovelhas deslanadas no pós-parto, com maior incremento calórico para o nível de 1,5% e superioridade para as ovelhas Santa Inês, indicando maior adaptabilidade das ovelhas Morada Nova quando submetidas à dieta concentrada em sistema de pastejo.Palavras-chave: fatores ambientais, estresse calórico, nutrição, termorregulação.

Crude glycerin inclusion in Santa Inês ewes’ diet before and during the breeding season: its effects on physiological parameters, hematological variables, and reproductive performance

“…This process, known as caloric increase, generates heat. In the case of arid and semi-arid regions, thermal stress is considered the most intriguing factor to negatively influence animal production (Pereira et al, 2014;Rocha et al, 2014). Heat stressed animals reduce their caloric intake, thereby reducing their basal heat production, which, consequently, results in the activation of all the physiological variables such as RR, RH, RT.…”

Ingestive Behaviour of Grazing Ewes Given Two Levels of Concentrate

“…This behaviour is possibly because of the search for greater dissipation of heat produced via the heat increment of the diet and environmental conditions. The impact of these factors becomes more pronounced in animals raised on pasture because their interaction can cause intense physiological disturbances (Sijean et al, 2010;Silva et al, 2013;Rocha et al, 2014).…”

<b>Effect of concentrate supplementation and time scales of evaluation on behavioral and physiological responses of pregnant ewes on grazing system

“…Respiratory rate in Santa Inês ewes was above the physiological limit for sheep (Marai et al, 2007). Respiration is the most important variable to maintain homeostasis in sheep (Starling, Silva, Cerón-Muño, Barbosa, & Costa, 2002), being the physiological variable most affected in animals kept under heat stress conditions (Rocha et al, 2014). Environmental factors combined with heat increment of concentrate supplementation are factors that affect the physiological parameters and may cause loss of productivity of the studied breeds.…”

“…HR is influenced by turn of the day and with a higher beat frequency in the afternoon, probably due to rise in thermal environmental parameters and with an increase in animal discomfort (Rocha et al, 2014). The increase in RR was result of a progressive accumulation of heat due to adverse environmental factors (Table 2).…”

“…The main feature of this region is the scarcity and high irregularity in the distribution of rainfall. Combination these factors can cause intense discomfort to animals (Costa, Takeda, & Lima, 2010;Silva Souza Júnior, Santos, Marques, &Torreão, 2013b, Rocha et al, 2014. In additional, climate changes can interfere in the Acta Scientiarum.…”