Investimento em climatização na pré-ordenha de vacas girolando e seus efeitos na produção de leite

Abstract

RESUMOObjetivou-se, com este trabalho, avaliar os efeitos da climatização na pré-ordenha sobre o acondicionamento térmico, fisiologia, produção de leite e relação custo/benefício do sistema de resfriamento adiabático evaporativo (SRAE). Utilizaram--se 16 vacas com produção de 18 kg de leite d -1 , adotando-se delineamento em quadrado latino 4 x 4 e comparação entre as médias pelo teste de Tukey (P < 0,05). Os tratamentos adotados foram os tempos de exposição dos animais ao SRAE no curral de espera, 0, 10, 20 e 30 min. A temperatura de bulbo seco (Tbs) e umidade relativa (UR) foram registradas a cada minuto o que permitiu determinar a eficiência do SRAE por meio do índice de temperatura e umidade (ITU) e entalpia (h). A frequência respiratória (FR), temperatura retal (TR) e temperatura de pelame (TP) foram medidas antes e depois da climatização. O tratamento 30 min permitiu manter as variáveis ambientais e os índices de conforto entre os limites recomendados. As variáveis fisiológicas (FR, TR e TP) mostraram valores inferiores no tratamento 30 min, o que refletiu positivamente na produção de leite, com aumento de 4,35%, quando comparado com o tratamento 0 min. O investimento no SRAE promoveu acréscimo na receita mensal, de R$ 1.266,84, com tempo de retorno do capital de 58 dias.Palavras-chave: bem-estar animal, bovinocultura de leite, conforto térmico, resfriamento evaporativo Investment in system in the pre-milking of girolando cows and its effects on milk production ABSTRACT The objective of this study was to evaluate the effects of cooling of pre-milking cows on production, physiology, thermal conditioning and the cost-benefit of the Adiabatic Evaporative Cooling System (AECS). Sixteen cows were used with an average daily milk production of 18 kg, distributed in 4 x 4 Latin square design. The Tukey test (P<0.05) was utilized for comparison of means. The treatments (0, 10, 20 and 30 min.) consisted of exposure of pre-milking cows to the AECS. The dry bulb temperature (DBT, ºC) and relative humidity (RH, %) were recorded every minute, which allowed the determination of the efficiency of the AECS through the temperature and humidity Index (THI) and enthalpy (h). The respiratory rate (RR), rectal temperature (RT) and temperature of the coat (TC) were measured before and after cooling. The 30 min. treatment kept the environmental variables and the comfort indexes within recommended limits. The physiological variables (RR, RT and TC) were lower in the 30 min treatment and reflected positively on milk production, which increased 4.35% compared to the control treatment (0 min). The investment was profitable having a 58 day return on investment and a monthly revenue increase of R$ 1,266.84.

<b>Assessing different holding pen cooling systems through environmental variables and productivity of lactating cows

“…Similar reductions were found by Almeida et al (2010), who reported average DBt values of 24.3°C for 30 minutes of climatization with misting plus ventilation. Relative air humidity showed the opposite behavior compared to DBt.…”

“…Almeida et al (2010), assessing a holding penclimatization system by misting, obtained a time of 58 days for return on investment. Silva et al (2011), in turn,observed a better result with 40 minutes of misting climatization, reporting 43 days for return on investment.…”

“…Silva, Pandorfi, Almeida, Guiselini and Henrique (2011) verified a 3.66% increase in milk production as of the implementation of a climatization system with shading, ventilation and water sprinkling. Almeida, Pandorfi, Guiselini, Almeida and Morril (2010), in their turn, found an increase of 4.35% in the milk production of cows subjected to climatization with a similar system. Nevertheless, to analyze the viability of a climatization system, the productive response alone is insufficient, because the adoption of costly measures to mitigate the effects of thermal stress can make its use unfeasible, especially when the number of animals in production is not enough to dilute, in the short term, the fixed costs of the technology adopted, and productivity gains are not sufficiently high to offset the investment (Cerutti, Bermudes, Viegas, & Martins, 2013).…”

Physiological parameters, hair coat morphological characteristics and temperature gradients in holstein-gyr crossbred cows

“…The effects of heat stress on the productive efficiency (FACÓ et al, 2002;ALMEIDA et al, 2010), the expression of behaviors indicative of thermal discomfort (BORGES et al, 2012) and thermoregulatory characteristics in summer (LIMA et al, 2013) have been reported for Gyrolando cows. However, research studies on the different genetic groups that make up the Gyrolando breed are scarce.…”

Índice De Desconforto E Índice De Temperatura Efetiva: Uma Implementação Para Smartphones E Tablets.

“…Diretrizes de conforto térmico são essenciais para o embasamento de projetos de instalações adequados à climatização (AZIZPOUR et al, 2013), nos dias atuais ambientes confortáveis são extremamente importantes, visto sua grande relação com a eficiência e qualidade produtiva, tanto para humanos (CHEN, VICTOR E CHANG, 2012;DIN et al, 2014;BATIZ et al, 2009;KUCHEN et al, 2005), como também, por exemplo, para animais (PASSINI et al, 2009;ALMEIDA et al, 2010;NAZARENO et al, 2012;HERMUCHE et al, 2013). A fim de analisar o conforto de ambientes, atualmente há métodos que, por meio de variáveis meteorológicas, possibilitam a definição de níveis de estresse térmico.…”