Influence of ventilation regimen on micro-environment and on ewe welfare and milk yield in summer

Abstract

The effects of ventilation regimen on air quality, and on the welfare and production performance of thirty-six Comisana<br />ewes were assessed in a 6-week trial conducted during the summer of 2002. Animals were divided into three groups of<br />12, and subjected to the following treatments: low ventilation regimen providing a mean ventilation rate (VR) of 35 m3/h<br />per ewe, split in 30 min ventilation cycles at an air speed of 2 m/s (LOV-30); moderate ventilation regimen (VR = 70<br />m3/h per ewe) split in 30 min ventilation cycles at an air speed of 4 m/s (MOV-30); moderate ventilation regimen (VR =<br />70 m3/h per ewe) split in 60 min ventilation cycles at an air speed of 2 m/s (MOV-60). Air concentrations of microorganisms,<br />dust, and gaseous pollutants were measured twice weekly. Respiration rate (RR) and rectal temperature (RT)<br />were monitored throughout the trial at 0830 and at 1400. Behavioral traits of ewes were recorded twice per week from<br />0900 to 1200 and from 1500 to 1800. Cell-mediated immune response to phytohemagglutinin (PHA) and humoral<br />immune response to chicken egg albumin were determined. At d 37 ewes were injected with porcine ACTH, and subjected<br />to blood sampling for evaluation of cortisol concentrations immediately before and 1, 2 and 4 h after ACTH injection.<br />Milk yield was recorded daily. Individual milk samples were analyzed for composition, renneting parameters, somatic<br />cell count (SCC), and bacteriological characteristics. Averages of maximum THI were about 3 points higher in the LOV-<br />30 and the MOV-30 than in the MOV-60 room, whereas no differences emerged in the air concentrations of dust, gaseous<br />pollutants and microorganisms. Significant interactions of treatment x time (P < 0.05) were found for respiration rate,<br />and for the time the ewes spent lying, idling and eating in the afternoon during weeks 2 and 3 of the study period.<br />Significant effects of ventilation regimen x time (P < 0.05) were also observed for milk yield and milk renneting parameters,<br />the LOV-30 ewes giving smaller volumes of milk with a deteriorated coagulating behavior than those of the MOV-<br />60 group during the second half of the trial. No significant differences emerged in ewe immune and endocrine responses.<br />Results show that ventilation regimen had a moderate impact on ewe behavior, physiology and production performance.<br />This experiment suggests that the length of ventilation cycles and air speed, together with ventilation rate, are<br />critical for efficient ventilation regimens

Effect of different ventilation regimens on ewes' milk and Canestrato Pugliese cheese quality in summer

“…Results of an earlier study (Sevi et al 2003a) show that the length of ventilation cycles and air speed, together with ventilation rate, are critical for optimizing the cheesemaking properties of ewes' milk during the summer season. In particular, the renneting properties of milk may be improved by increasing the ventilation rate from 35 to 70 m 3 /h per ewe or by increasing the length of ventilation cycles from 30 to 60 min, while keeping the ventilation rate constant at 70 m 3 /h.…”

“…The experimental location and animal management have been described previously (Sevi et al 2003a). Briefly, the experiment was conducted during the summer (June-July) of 2002 in the province of Foggia (latitude: 418 27k 6a and longitude : 158 33k 5a) and involved thirty-six lactating Comisana ewes.…”

“…6 m above the floor. Air concentrations of micoorganisms were measured, as described by Sevi et al (2003a). DIGIT ISO pumps (Zambelli, Bareggio-Milan, Italy) were used to record the air concentrations of total dust (particulate size > 5 mm) and respirable dust (particulate size = 2-5 mm).…”

“…These changes in milk composition have obvious implications for its manufacturing potential, e. g. impaired coagulation properties and reduced cheese yield (Lucey, 1996). Sevi et al (2003a) showed the choice of a proper ventilation regimen to be critical for optimizing the hygienic quality and the coagulating behaviour of ewes' milk, given that high ambient temperatures and poor ventilation rates may strongly enhance the growth and multiplication of microorganisms in the air and litter of dairy sheep houses (Sevi et al 2002).…”

“…In a previous study (Sevi et al 2003a), we investigated the effects of three summer ventilation regimens, varying in air speed and length of ventilation cycles, on air quality and on behavioural, immune and endocrine responses and on the performance of lactating ewes. In the present study, the influence of ventilation regimens on ewe bulk milk composition, and on microbial, chemical, and enzymic characteristics of Canestrato Pugliese cheese was evaluated.…”