Effect of simulated ambient particulate matter exposure on performance, rectal temperature, and leukocytosis of young Spanish goats with or without tilmicosin phosphate

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 simulated dust events or no dust, with or without tilmicosin phosphate treatment in a 2 x 2 factorial arrangement of treatments to determine effects on performance, rectal temperature, and leukocyte changes. All goats were fed a standard growing diet (13.6% CP) consisting of 37% roughage and 63% concentrate (DM basis). Feed intake was measured daily, and BW (unshrunk) measured individually every 7 d. The tilmicosin-treated group received tilmicosin phosphate (10 mg/kg BW s.c.) before starting the study. Goats exposed to dust were enclosed as a group inside a canvass tent for 4 h each day and ground feed yard manure dust (mean particle size 100 microm) was aerosolized inside the tent to simulate a dust event. There was one single dust event (Phase I) followed by rectal temperature measurement, and heparinized blood collection for complete cell counts at 0 (pretrial), 4, 12, 20, 44, 68, and 210 h after dust exposure. This was followed by 21 d of chronic dust events (Phase II). The sampling procedures for Phase II were exactly the same as in Phase I, except that samples were obtained daily at 0 (before dust application), 4, 8, and 12 h after each dust event. Dust treatment had no effect (P > 0.05) on feed intake or ADG, but the gain:feed (G:F) ratio was lower (P < 0.05) in the control goats than the dust exposed group. Tilmicosin phosphate-treated goats had a higher (P < 0.05) G:F ratio than untreated goats. Dust exposure increased (P < 0.002), but tilmicosin treatment decreased (P < 0.05) rectal temperature at 4 and 8 h. Dust exposure increased (P < 0.02) blood lymphocyte counts compared with controls. These results suggest that simulated dust events altered rectal temperature and leukocyte counts of goats.

Influence of clostridial vaccines and injection sites on performance, feeding behavior, and lesion size scores of beef steers

Several clostridial vaccines are currently being used in the beef cattle industry. Of greatest concern is altering the location and route of administration of these vaccines to reduce injection-site lesions while maintaining seroconversion. Two experiments were conducted to determine the effect of clostridial vaccines and injection sites on the performance, feeding behavior, and lesion size scores of beef steers. In Exp. 1, 80 crossbred beef steers (BW 237 +/- 3.2 kg) were allotted randomly into five groups and given 14 d to adapt to the feed and individual feed intake-monitoring devices (Pinpointer devices) before starting the study. Each group was assigned randomly to one of the following vaccination treatments: 1) control (sterile saline water), 2) Alpha-7 Ear (A7E), 3) Alpha-7 Prescapula (A7P), 4) Vision-7 Prescapula (V7P), and 5) Ultrabac-7 Prescapula (U7P). All vaccines were injected s.c. in the ear or prescapular region, and injection sites were palpated on d 0 and 28 (Exp. 1) and on d 63 and 91 (Exp. 2). The protocol for Exp. 2 was exactly the same as for Exp. 1 except treatments included control, A7P, Alpha-CD Ear (ACDE), Alpha-CD Prescapula (ACDP), Fortress-7 Prescapula (F7P), and V7P. Also, control and steers receiving F7P and V7P were revaccinated on d 63 and palpated on d 91. Results of Exp. 1 indicated that the A7E and U7P steers had a feed intake lower (P < 0.01) than all other treatment groups. The ADG of the A7P and A7E steers were not different (P > 0.05) from those of the control steers. The gain:feed ratio of the A7E steers was 41% higher (P < 0.01) than that of the V7P steers (Exp. 1). The results of Exp. 2 indicated that the control, ACDP, and V7P steers had greater (P < 0.01) ADG than all other treatment groups, but the gain:feed ratios were not different (P > 0.05) among all treatment groups. Lesion sizes differed by vaccine and injection site in both experiments. These data suggest that vaccinating beef steers s.c. in the ear produced gain:feed ratios and lesion size scores that were similar to prescapular vaccinations. However, more research is required to determine the immune response of vaccinating cattle in the ear.