No abstract

. 1994. Seasonal variation in intake and digestion of a high-roughage diet by muskoxen. Can. J. Anim. . We studied changes in body weight, intake, retention time and apparent digestibility of a supplemented brome-alfalfa hay by mature muskoxen held near Saskatoon, Saskatchewan during two seasonal cycles. Body weights and voluntary intake were monitored during 16 Le poids corporel moyen (+ ET) des femelles f6condes atteignait un maximum en f6vrier et en mars (248 ! 5 kg) et un creux imm6diatement aprds le vOlage en fin mai-d6but juin (216 + 6 kg). Chez les femelles hyst6rectomis6es, le poids moyen baissait l6gBrement de 228 ! 2.J_!g en f6vrier ir 213 + 2l kg en juillet-Ir'ing6r6 alimentaire moyen (m.s.) des femelles f6condes allait de62t 3,69j-'kg-u''enjuillet-ag0-te4l +0,7gj-rkg-u'/)enmars-avril._-Chezlesvacheshyst6rectomis6es. I'effet6tail moins marqu6:4,2 * 1,7 g j-'kg-'''' en fin d'hiver et 50 + 4,9 gS-tkg-u'r: ' h mi-6t6. La dur6e de r6tention moyenne des aliments, mesurde au moyen d'un moddle non compartimentd diminuait significativement de 114 * 4 h en mars )r 95 * 4 h en juillet. ta digestibilit6 apparente de la matidre organique diminuait de fagon significative de74,7 + 0,8Vo en hiver d61,7 + 1,3% en 6t6. Compar6 aux autres ruminants, le boeuf musqu6 est un herbivore particulibrement bien adapt6 ir la digestion de

Dietary undetermined anion (dUA) reflects, in part, the net acid load contributed by the diet. Although dUA is known to influence performance and nutrient metabolism of swine, a lack of knowledge impairs its application to diet formulation. This study was undertaken to separate the effects of dUA from the individual electrolytes that constitute its calculation. Eighteen 35-kg pigs were fitted with indwelling venous catheters and fed one of three barley and soybean meal-based diets: a control diet (C), an acidogenic diet containing calcium chloride (A), or a compensated acidogenic diet containing alkaline salts of sodium and potassium, as well as calcium chloride (CA). Compared with diet C, diet A lowered (P < .05) blood pH, bicarbonate, and base excess and increased (P < .05) urinary ammonium, titratable acid (TA), and net acid excretion (NAE). Diet CA returned blood acid-base values to normal and reduced urinary ammonium, TA, and NAE relative to diet A. Total nitrogen balance was unaffected by diet. Diet CA increased (P < .05) water intake and urine output. Diet A, but not CA, increased (P < .05) serum ionized Ca and C1. Apparent Ca and S digestibility and retention were reduced by diet A, but not by CA. Sodium retention was enhanced (P < .05) by diets A and CA; potassium retention was impaired (P < .05) by CA. Dietary UA altered systemic and renal acid-base balance in pigs. Mineral, but not nitrogen, metabolism was affected by both dUA and specific ion effects.

. 1986. Somatostatin immunization and growth of lambs. Can. J. Twenty cross-bred lambs were used in a replicated design to measure the growthpromoting effect of immunization against somatostatin. The lambs were immunized against human alpha-globulin (control) or against somatostatin coupled to human alpha-globulin in a l:3.75 ratio (wtiwt) (SI)

1. The relative importance of excretory routes in the removal of recently stored 67Cu following tetrathiomolybdate (TTM) administration was studied. Lambs fed on either 5 mg Cu/kg dry matter (DM) or 35 mg Cu/kg DM, were primed intravenously (iv) with 87Cu and challenged 27 h later with gsMo-labelled TTM given either iv or intraduodenally (id). The profiles of "Cu and esMo and of Cu and Mo in blood, bile, urine and faeces were measured.2. Level of dietary Cu and route of administration of "Mo-TTM affected the amplitude of blood, bile and urine profiles of 67Cu and stable Cu, but not the pattern of the responses observed.3. The present study describes for the first time increased excretion of endogenous 87Cu through gastrointestinal secretions other than bile due to TTM administration.4. Administration of TTM resulted in the immediate release of 67Cu from storage compartments in the body into the blood circulation. Changes in stable Cu levels in blood, bile, urine and faeces, and gut and systemic effects were evident, Biliary and urinary Cu excretion due to TTM was rapid and maximal within 24 h of injection.5. Administration of "Cu iv resulted in the immediate excretion of "Cu in bile in a pulsatile, constant pattern. A similar pattern of 87Cu excretion into bile in synchrony with that of OOMo was observed after esMo-labelled I T M administration.6. The similar pattern of biliary 67Cu excretion observed after injection of 'lCu and after injection of geMolabelled TTM 27 h later is discussed in relation to the times required to process the Cu through different hepatic pathways for excretion in bile.Molybdenum and sulphur-induced copper deficiency in ruminants (Mills, 1985) is probably mediated through the thiomolybdates (TM) (MoO,S,., where n is 0-3). Di-and trithiomolybdates predominate in plasma of sheep given either normal or slightly elevated levels of Mo . 1981 a). Most of the increased Cu in plasma is present in an unidentified trichloroacetic acid (TCA)-insoluble form, the source