To compare the effects of milk stasis and milk flow on Brucella abortus infection of the mammary gland under the same systemic conditions, primiparous goats (n = 5) were inoculated IV with B abortus on the day of parturition, and suckling by their neonates was restricted to one mammary gland. Goats were euthanatized and necropsied at 3 weeks after inoculation, and milk, mammary glands, and supramammary lymph nodes were evaluated by bacteriologic, histologic, and immunoenzymatic staining techniques. Nonnursed mammary glands had high titers of brucellae in milk, moderate interstitial mastitis, and brucellar antigen in macrophages located primarily in alveolar and ductal lumina. Brucellae often filled the macrophage cytoplasm. In contrast, nursed mammary glands had fewer brucellae in milk, minimal inflammatory changes, and no detectable brucellar antigen in histologic sections. Hyperplastic changes were only seen in supramammary lymph nodes draining nonnursed mammary glands; these contained more brucellae than lymph nodes draining nursed mammary glands. These studies show that milk stasis may be the sole cause of increased susceptibility of nonnursed mammary glands to B abortus infection.

We compared the frequency and severity of osteochondrosis lesions in young Thoroughbred horses with cervical stenotic myelopathy (CSM) vs that in clinically normal Thoroughbreds of the same age. All lesions of the cervical vertebrae and appendicular skeleton were classified histologically as osteochondrosis or nonosteochondrosis and were measured for severity. Minimal sagittal diameter was significantly smaller in horses with CSM from C2 through C6; no difference was detected at C7. Severity of cervical vertebral osteochondrosis was greater in the horses with CSM, however frequency was not different. Frequency and severity of nonosteochondrosis lesions were not different in cervical vertebrae or appendicular skeleton. Frequency and severity of appendicular skeleton osteochondrosis lesions were both greater in horses with CSM. Osteochondrosis and nonosteochondrosis lesions were more severe on facets at sites of compression than on facets at noncompressed sites in horses with CSM. However, compression was also observed at sites with no articular facet lesions. The association of widespread osteochondrosis and spinal canal narrowing with CSM suggests CSM may represent a systemic failure in the development or maturation of cartilage and bone.

Analysis of hepatic enzyme activities in serum samples from 1- to 3-day-old pups revealed alkaline phosphatase (ALP) activities that were 30 times higher and gamma-glutamyltransferase (GGT) activities that were 100 times higher than activities in clinically normal adult dogs. A study was conducted to investigate high enzyme activity in pups and to determine whether there is any association between serum enzyme activity and colostrum ingestion, passive transfer of maternal serum enzyme (in colostrum or in utero), or excessive renal or hepatic tissue enzymes. Serum enzyme activity was quantified in 15 neonatal pups before and after ingestion of colostrum and in 3 colostrum-deprived neonates fed a milk substitute. Serum samples were collected on postpartum days 0, 1, 10, 15, and 30. Enzyme activity was also quantified in serum from pregnant and lactating bitches (collected on days - 2, 0, 1, 10, 30), hepatic and renal tissue from clinically normal adult dogs and 1-day-old pups, colostrum, milk (collected on days 10 and 30), and milk replacer. Significant (P < 0.01) differences in serum GGT and ALP activities between colostrum-deprived and suckling pups did not exist before initial feeding. Significant (P < 0.001) increases in serum GGT and ALP activities developed within 24 hours in suckling pups, but not in the colostrum-deprived pups. At 10 and 30 days after birth, serum GGT and ALP activities were less than values before suckling in all pups. Enzyme activities in bitches' serum remained within the normal range for adult dogs throughout whelping and lactation. Renal GGT and ALP activities were substantially greater than hepatic enzyme activities in neonates and adults. Renal tissue from adults contained 3 times greater GGT and 2 times greater ALP activities than that from neonates. Hepatic tissue from neonates contained 5 times more GGT activity than did hepatic tissues from clinically normal adults; however, hepatic ALP activity was similar in adults and neonates. Colostrum and milk bad substantially higher enzyme activities than did bitches' serum. Activities of GGT and ALP in milk were 100 times and 10 times greater, respectively, than activities in serum through day 10. By day 30, GGT and ALP activities in milk were less than before suckling. Enzyme activity was not detected in the milk substitute. These studies reveal an association between colostrum ingestion by suckling and acute, profound increases in serum GGT and ALP in 1- to 3-day-old pups. Although this phenomenon might be useful as an indicator of colostrum ingestion, it precludes the diagnostic use of either enzyme as an indicator of hepatobiliary disease in 3-day-old pups.