Airspace effects on the yield and quality of ewe milk.
Three groups of 12 midlactating Comisana ewes were housed in separate rooms of the same building and assigned to treatments of low (LV, 4.1 m3), medium (MV, 5.6 m3), or high (HV, 7.3 m3) airspace/animal. The concentrations of airborne microorganisms in the experimental rooms were measured twice weekly at 0930 and 1630. Ewe milk yield was recorded daily. Individual milk samples were analyzed weekly for milk composition, coagulating properties, somatic cell concentration (SCC), and polymorphonuclear neutrophil leukocyte count (PMNLC), and fortnightly for bacteriological characteristics; samples with more than 10(6) somatic cells/ml were cultured for mastitis-related pathogens. The LV and MV treatments resulted in higher relative humidity and air concentrations of staphylococci than the HV treatment. Greater amounts of air mesophilic bacteria were also found in the LV than in the HV room. Ewes in the HV group gave greater yields of milk than those in the LV and MV groups. LV milk also had a lower casein content than HV milk. Significant interactions of treatment x time were found for milk protein and fat content as well as for clotting time and clot firmness, with LV milk having the poorest composition and deteriorated renneting ability during the last 3 wk of the trial. The HV ewes had lower SCC and PMNLC and psychrotroph counts in their milk than LV and MV ewes and smaller amounts of mesophilic bacteria and fecal coliforms than LV animals. Subclinical mastitis occurred in two ewes of the LV and one of the MV groups, while no cases were recorded in the HV group. Results suggest that airspace is a critical factor in dairy sheep housing and indicate that a volume allocation of less than 7 m3/animal may adversely affect the performance and health of the lactating ewe.
Sevi
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Istituto di Produzioni e Preparazioni Alimentari, Facoltà di Agraria, Foggia, Italy. agostinosevi@tiscalinet.it
Taibi
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L
Albenzio
M
M
Annicchiarico
G
G
Muscio
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D000391:Air Microbiology; D000822:Animal Husbandry; D000818:Animals; D002452:Cell Count; D005260:Female; D006799:Housing, Animal; D006920:Hygiene; D007774:Lactation; D008413:Mastitis / Q000453:epidemiology / Q000209:etiology; D008892:Milk / Q000166:cytology / Q000378:metabolism* / Q000382:microbiology / Q000592:standards*; D012756:Sheep / Q000502:physiology*