Effects of weaning pigs to different diets have been investigated in terms of the changes in the small intestinal morphology, and in the absorption of short-chain fatty acids (SCFA) and sodium from the large intestine. One piglet from each of six litters containing nine pigs was sampled on the day of weaning; the other eight piglets were divided into four equal groups and fed different diets as follows: unweaned, weanling diet, or sow's milk at high or low level. Four and seven days after weaning, measurements of the intestinal tissue and contents were made; the plasma concentrations of SCFA, aldosterone and sodium were also measured. The villous height in the small intestine was highest in the unweaned group and greater in the high milk group than in either the weanling diet or low milk group (P < 0.001). Apparently, villous atrophy was due more to the level of feed intake than to the composition of the diet. The concentrations of SCFA in the large intestine and portal blood were highest in the weanling diet group and lowest in the low milk group. The low milk group tended to have higher blood concentrations of aldosterone (P = 0.15), which may have compensated for the low concentrations of SCFA in maintaining a higher percentage of dry matter in the intestine. Pigs fed weanling diet may use the energy from the SCFA to maintain a body weight comparable to that of pigs fed milk at a low level.

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In 41 veal calves divided into three groups and fed different levels of dietary iron, blood hemoglobin, plasma iron, liver, spleen, and muscle iron, muscle heme pigment, and carcass muscle color at slaughter were studied. At 45 min postmortem, total carcass color was visually evaluated in the 41 carcasses. In different muscles of the carcasses the color was measured instrumentally using an invasive color measurement method at 45 min postmortem (MCDI score) and a surface color measurement method at 20 h postmortem (Minolta L*, a*, b*, and Chroma scores). Among the three groups, differences (P less than .05) in muscle iron concentrations, muscle heme pigment concentrations, and Minolta a*, b*, and Chroma scores were found. Most striking were the differences in mean iron concentrations in the longissimus thoracis muscles between Groups A (29 micrograms/g DM) and B (44 micrograms/g DM) and in the semimembranosus muscles between Groups A (31 micrograms/g DM) and C (45 micrograms/g DM). The correlations found between Minolta L*, a*, or Chroma score and the iron and heme pigment concentrations in the semimembranosus muscles were high in comparison with those found in the longissimus thoracis and rectus abdominis muscles. Compared with the plasma iron concentration, the blood hemoglobin concentration showed higher correlations with muscle iron and muscle heme pigment concentrations. It can be concluded that different iron concentrations in the milk replacer during the first 7 wk of fattening influence, to some extent, muscle iron and muscle heme pigment at slaughter. However, these differences were not measurable in the overall visual color evaluation of the carcass surface muscles.

The biopharmaceutical properties of four fixed trimethoprim/sulfonamide combinations were investigated in the horse. Eight fasted horses were dosed at 1 week intervals in a sequentially designed study with one intravenous (i.v.) and three oral trimethoprim/sulfadiazine (TMP/SDZ) formulations (1, 2 and 3) administered at a dose of 5 mg/kg trimethoprim (TMP) and 25 mg/kg sulfadiazine (SDZ). Plasma concentrations of each compound were monitored for 48 h. Pharmacokinetic parameters (volume of distribution, bioavailability and total body clearance) for TMP and SDZ were calculated and compared. After oral administration plasma concentrations of TMP and SDZ increased rapidly. With all three paste formulations, TMP peak plasma concentrations were attained within 2 h. SDZ mean peak plasma concentrations were reached at 2.59 +/- 0.48 h for a commercial paste (1), and at 1.84 +/- 0.66 h and 1.95 +/- 0.61 h for the two self-made formulations (2 and 3). Mean peak plasma TMP concentrations (+/- SD) were 1.72 +/- 0.36 micrograms/ml, 1.42 +/- 0.37 micrograms/ml and 1.31 +/- 0.36 micrograms/ml, and mean peak plasma SDZ concentrations 12.11 +/- 4.55 micrograms/ml, 12.72 +/- 3.47 micrograms/ml and 15.45 +/- 4.74 micrograms/ml for preparations 1, 2 and 3. The bioavailability of TMP was 67.0 +/- 20.3%, 57.7 +/- 21.6% and 60.9 +/- 18.9% and of SDZ 57.6 +/- 14.8%, 59.3 +/- 19.5% and 65.9 +/- 5.8% for SDZ for 1, 2 and 3, respectively. Following i.v. administration TMP/SDZ plasma concentration ratios approached the optimal 1:20 ratio (+/- 10%) for about 5 h, but following the oral administrations this ratio was only achieved for a very short time-span.(ABSTRACT TRUNCATED AT 250 WORDS)