Submitted to: Animal Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/7/2003
Publication Date: 4/1/2004
Citation: Chirase, N.K., Purdy, C.W., Avampato, J.M. 2004. Effect of simulated ambient particulate matter exposure on performance, rectal temperature and leukocytosis of young spanish goats with or without tilmicosin phosphate. Animal Science. 82:1219-1226 Interpretive Summary: The effect of ambient organic dust on the health and production of ruminants is not well understood. However, dust events are common in agriculture where ruminants are confined and concentrated in animal feeding operations. One induced 4 hr dust event followed by repeated dust events on goats while confined in a tent were compared to non-dusted control goats in performance, rectal temperature, total white blood cells changes, and their response to tilmicosin antibiotic treatment. The results indicated that organic dust treatment had no effect on feed intake or average daily gain but the Gain:Feed (G:F) ratio was lower in the control goats than the dust exposed group. Tilmicosin antibiotic treated goats had higher G:F ratio than untreated goats. Dust/endotoxin (component of Gram-negative bacteria) increased rectal temperature in 4 to 8 hrs and white blood cells in 12 to 24 hrs after the first dust event. The effect of organic dust on the performance and health of ruminants is complicated. This research is a beginning effort to better understand the effect of dust/endotoxin on the production and health of ruminants.
Technical Abstract: Dust is an environmental stressor and can become extensive in agricultural production systems. Thirty-six female, Spanish goats (average BW 21.1 kg, SEM = 1.31; age = 4 mo.) were randomly assigned to dust and tilmicosin treatments in a 2 X 2 factorial arrangement of treatments and was used to determine effects of simulated dust events on performance, rectal temperature (RT) and leukocytes changes of goats with or without tilmicosin treatment. All goats were fed a standard growing diet consisting of 37% roughage, 63% concentrate and 13.6% crude protein. Feedintake was measured daily and body weight (BW) meaured individually every 7 days. The tilmicosin treated group received tilmicosin phosphate (10 mg/kg BW subcutaneously) before starting the study. Goats exposed to dust were enclosed as a group inside a tent for 4 hr each day and ground feedyard manure dust (mean particle size 100 micrometers) was aerosolized inside the tent to simulate a dust event. There was one single dust event (phase I) followed by RT measurement and heparinized blood collection for complete cell counts at 0 (pretrial), 4, 12, 20, 44, 68, and 210 hr post-dust exposure. This was followed by 21 days of chronic dust events (phase II). The sampling proceedure was similar for both phases. The results indicated that dust treatment had no effect (P> 0.05) on feed intake or average daily gain (ADG) but the Gain:Feed (G:F) ratio was lower (P < 0.05) in the control goats than the dust exposed group. Tilmicosin treated goats had higher (P < 0.05) G:F ratio than untreated goats. Dust exposure increased (P < 0.002) but tilmicosin lowered (P < 0.05) RT at 4 and 8 hrs. Dust/endotoxin exposure increassed (P < 0.02) blood leukocyte counts compared with controls.