Effects of monensin on Mg, Ca, P and Zn metabolism and tissue concentrations in lambs

A study consisting of two trials was conducted to determine the effects of monensin on the apparent absorption and retention of magnesium (Mg), phosphorus (P), calcium (Ca) and zinc (Zn) and to determine mineral changes in tissue and ruminal fluid. Eight lambs (39 kg) were used in trial 1, and 10 lambs (37 kg) were used in trial 2. Animals were blocked by weight and fed a high concentrate diet with or without 20 mg/kg monensin. Trials began with a dietary adjustment period lasting 18 d in trial 1 and 21 d in trial 2. Animals were then placed in metabolism stalls for a 10-d stall adjustment period followed by a 12-d collection period. Collections to determine mineral balance were made during the first 10 d of the collection period. Blood and ruminal fluid samples were taken on d 11 of the collection period. Lambs were slaughtered on d 12 of the collection period and tissue samples were collected. Monensin supplementation increased (P less than .05) Mg retention 42.0%. Urinary Ca excretion decreased (P less than .05) 60.0% when monensin was fed. Monensin supplementation decreased (P less than .05) liver Ca and bone Ca, 45.5 and 2.9%, respectively. Apparent P digestibility increased (P less than .05) 40.0% and P retention increased (P less than .10) 26.8% due to monensin supplementation. Both apparent absorption and retention of Zn increased (P less than .01) 50.0 and 45.0%, respectively, with monensin supplementation. Ruminal fluid Zn concentrations decreased (P less than .05) 33.0% with the addition of monensin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Prevalence of leukemic blood and bone marrow in dogs with multicentric lymphoma

Multicentric lymphoma was diagnosed in 53 dogs. A study was performed to evaluate the prevalence of leukemic involvement in blood samples, bone marrow aspirates, and bone marrow core biopsy specimens at the time of initial diagnosis. Data indicated that 57% (30/53) of the dogs were leukemic when all materials were considered relative to the presence of cellular atypia or immaturity and abnormal tissue distribution. In the 30 leukemic dogs, detection was made in the specimens with the following frequency: 15 in blood (50%), 18 in bone marrow aspirates (60%), and 29 in bone marrow core biopsy specimens (97%). Five cases (17%) were only detected by core biopsy examination, even when dogs with bone marrow lymphocytosis of greater than 15% of nucleated cells were considered leukemic. Nondiffuse histologic colonization patterns accounted for the lack of correlation between the type of bone marrow specimens. Clinical staging for treatment response and prognosis was best determined by evaluation of concurrently obtained blood samples, bone marrow aspirates, and bone marrow core biopsy specimens.     

Environmental source of mycobacteriosis in a California swine herd.

Between July 1985 and April 1986, mycobacterial lymphadenitis was recorded in six of 2407 slaughter pigs from a commercial swine herd in which the majority of pigs were raised in confinement. Records showed that all six affected pigs had access to dirt-floored pens at least 81 days prior to slaughter. The mycobacteriosis lesion rate for pigs exposed to dirt pens was 9.4% while in nonexposed pigs the lesion rate was zero. The risk associated with movement of pigs from concrete floored pens to dirt pens was evaluated by a field trial. In the field trial, two litters (5 of 15 pigs) exposed to dirt pens at 12-24 days of age but none of nine nonexposed litters (39 pigs) developed lesions. Mycobacterium avium-complex bacteria were recovered from both exposed litters (9 of 15 pigs) but from none of nine nonexposed litters. Serovars of M. avium-complex isolated from trial pigs included 1, 4, 8, 9, the dual serovar 4/8, and an untypable serovar. Incense-cedar bark (Calocedrus decurrens) used as a flooring material in the pens was demonstrated to be a potential source of M. avium-complex serovar 9. The dual serovar 4/8 and an untypable M. avium-complex were isolated from the dirt-floored pens. No evidence of cross-transmission of M. avium-complex infection was detected. The sporadic pattern of mycobacteriosis observed in the herd probably resulted from infrequent exposure to a common environmental source.     

The effect of Harderian adenectomy on the antibody response in chickens

Intact chicks and those that had their glands of Harder (GH) removed (GHx) at 1 day of age were studied for their response to optically or intraperitoneally (IP) applied antigens. Following exposure of the chicks to sheep red blood cells (SRBCs), killed Brucella abortus, or bovine serum albumin (BSA), serum and tear samples were collected and assayed for antibodies. Of the two sources of antibodies, the serum generally had higher levels than did the tears. The only exception to this occurred in the intact chicks inoculated by the eye, in which serum and tear levels were equivalent. With SRBCs, no difference could be detected between the two routes of inoculation. However, IP inoculation produced higher levels of antibody in the serum of intact and GHx chicks inoculated with B. abortus or BSA and in the tears of the GHx chicks exposed to B. abortus. Removal of the GH resulted in a consistent decrease in antibody levels in the tears, regardless of the route of exposure. Although this effect was noted with all three antigens, it was more pronounced in the trials using B. abortus and BSA. This finding is discussed in terms of describing the importance of the GH as a source of antibodies to optically applied antigens, and its importance as a route of circulating antibody egress. Furthermore, the feasibility of using the antibody response in tears to a test antigen is discussed as a means of measuring the immune status of a functioning GH.     

Alteration of nitrogen metabolism by alpha-ketoglutarate administration in growing lambs fed high nonprotein nitrogen-containing diets

Two completely randomized design experiments were conducted, using either 10, 38-kg (Exp. 1) or 10, 26-kg (Exp. 2) Hampshire x Western wether lambs, to study the effects of alpha-ketoglutarate (AKG) administration on N metabolism. Lambs were fed 890 and 885 g DM/d in Exp. 1 and 2, respectively, of corn-cottonseed hull basal diets with urea added to attain CP levels of 10.6 and 10.5% in Exp. 1 and 2, respectively. Experiments consisted of 10 d of adaptation followed by 7 d of infusion and excreta collection. Lambs were infused continuously either i.v. (Exp. 1) or abomasally (Exp. 2) with control solutions (CON) or solutions containing 41.3 g AKG/d (AKG). In Exp. 1, fecal and urinary N excretion and N retention were not affected (P greater than .10) by treatment. Compared to CON in Exp. 2, AKG infusion increased (P less than .10) fecal N output (6.6 vs 5.9 g N/d) but did not affect (P greater than .10) the amount of N retained (4.4 vs 3.5 g N/d). Compared to CON, AKG increased (P less than .10) urinary NH3 N excretion in Exp. 1. Serum urea N was lower (P greater than .10) for AKG than for CON in Exp. 1 but was not affected (P greater than .10) by treatment in Exp. 2. In Exp. 1, AKG appeared to reduce activities of several serum enzymes that function in amino N metabolism. In Exp. 1, compared to CON, AKG decreased (P less than .10) aspartate but increased (P less than .10) asparagine in serum.(ABSTRACT TRUNCATED AT 250 WORDS)     

Parosteal osteosarcoma of the mandible in a dog

A mandibular parosteal osteosarcoma was diagnosed in a 7-year-old Collie with prolapse of the third eyelid. Diagnosis was made by histologic evaluation of a mass removed by surgical excision. The dog was euthanatized because of local recurrence of the tumor, with metastasis to the lungs. Parosteal osteosarcomas are rarely reported in dogs and usually involve long bones in human beings.     

Evaluation of the testosterone response to hCG and the identification of a presumed anorchid dog

A two-year-old dog was presented with no scrotal testes. There was no history of castration but at laparotomy no testes were found. To confirm that the dog was truly anorchid a human chorionic gonadotrophin stimulation test was performed. This was then validated in normal entire and castrated dogs.     

盐分对碱茅种子发芽影响的机制

耐碱茅种子在盐（NaCl与Na2SO4）及干旱（PEG－6000模拟）胁迫下发芽及其机制的比较研究表明，种子发芽率随溶液渗透势的降低而下降，在等渗条件下三种溶液中的发芽率次序为Na2SO4＞NaCl＞PEG。NaCl与Na2SO4主要通过影响种子吸水量及对膜的毒性影响发芽，根据相关及通径分析结果，其机制为：（1）溶液渗透势及Na+浓度决定的种子吸水对发芽的直接正效应（通径系数0．73）；（2）溶液Na+浓度引起的膜毒性对发芽的直接负效应（－0．51）；（3）种子从溶液中吸收Na使种子吸水增加对发芽的间接正效应（0．30）及使膜毒性增大对发芽的间接负效应（－0．24）。