Targeting therapy to minimize antimicrobial use in preweaned calves: Effects on health, growth, and treatment costs

Prophylactic and therapeutic antimicrobial use in food animals is questioned because of the potential for development of resistant bacteria and future inability to use some antimicrobials for human or animal disease. The objectives of this study were to determine the effect of raising preweaned dairy calves without antimicrobials in the milk and minimizing therapeutic antimicrobial treatment on morbidity, mortality, weight gain, and treatment costs. Newborn calves (n = 358) were allocated to 1 of 4 groups, housed outdoors in individual hutches, and monitored for 28 d. Calves in the conventional therapy (CT) group were treated as per dairy protocol with sulfamethoxazole/trimethoprim, spectinomycin, penicillin, and bismuth-pectin for diarrhea. The targeted therapy (TT) group included bismuth-pectin for diarrhea and antimicrobial treatment only in cases of fever or depressed attitude. Within CT and TT groups, calves were equally assigned to receive neomycin and tetracycline in their milk for the first 2 wk of life (AB-milk) or no antimicrobials (NoAB-milk). Daily health evaluations included fecal consistency, respiratory disease, attitude, and hydration status as well as milk and grain consumption. A negative binomial model evaluated the total number of days with diarrhea days in each group. General linear models were used to assess average daily weight gain and grain consumption. Conventionally treated calves had 70% more days with diarrhea than TT calves, and AB-milk calves had 31% more days with diarrhea compared with NoAB-milk calves. The TT calves tended to have a higher average daily gain by 28 d and consumed more grain compared with CT calves. If antimicrobials were used only for diarrhea cases with fever, inappetence, or depression and no in-milk antimicrobials were used, a $10 per calf savings could be realized. Targeting antimicrobial therapy of calf diarrhea cases is prudent not only to save the drugs for future use but also to prevent the potential for antibiotic-associated diarrhea and reduce calf-rearing costs

Association of nucleolar organizing regions and Ki-67 expression with recurrence rate of hair follicle tumor in dogs Associação das regiões organizadoras de nucléolos e da expressão do Ki-67 com a taxa de recorrência dos tumores de folículo piloso em cães

Mitotic index, nuclear diameter, number of nucleolar organizing regions, and Ki-67 expression, in hair follicle tumors of 82 dogs were evaluated. Tissue specimens were used to prepare sections for histological staining for number of nucleolar organizing region and immunohistochemical staining for Ki-67. Tumors were classified as trichoblastoma (n=32), benign trichoepithelioma (n=30), pilomatricoma (n=7), malignant trichoepithelioma (n=6), infundibular keratinizing acanthoma (n=5), and tricholemmoma (n=2). Head, dorsum, and limbs were the most affected sites. Malignant trichoepithelioma presented significantly higher mitotic index, number of nucleolar organizing regions and Ki-67 expression. Regarding benign neoplasms, trichoblastoma presented significantly higher mitotic index and number of nucleolar organizing regions. Ki-67 expression did not differ among hair follicle benign neoplasms. Recurrence was only observed in two cases, with one benign trichoepithelioma and one malignant trichoepithelioma. In the two cases, nodules have not been removed with clean surgical margin. It was concluded that in benign neoplasms of hair follicles, the number of nucleolar organizing regions and Ki-67 expression were significantly smaller than in malignant neoplasm. Clean surgical margins are suggested to be more responsible to tumor recurrences than the number of nucleolar organizing regions, expression of Ki-67, and the mitotic index.<br>O objetivo deste trabalho foi avaliar o índice mitótico, o diâmetro nuclear, o número de regiões organizadoras de nucléolos e a expressão do Ki-67 em 82 tumores de folículo piloso de cães, entre 2000 e 2006. Os tumores foram classificados como tricoblastoma (n=32), tricoepitelioma benigno (n=30), tricoepitelioma maligno (n=6), pilomatricoma (n=7), acantoma infundibular ceratinizante (n=5) e tricolemoma (n=2). A cabeça, o dorso e os membros foram os locais mais frequentemente acometidos. O tricoepitelioma maligno apresentou índice mitótico, número de regiões organizadoras de nucléolos e expressão do Ki-67 significativamente maiores quando comparado aos outros tipos de tumores. Dentre as neoplasias benignas, o tricoblastoma apresentou índice mitótico e número de regiões organizadoras de nucléolos significativamente maiores. A expressão do Ki-67 não diferiu entre os tumores benignos de folículo piloso. A recorrência foi observada apenas em dois casos, incluindo um tricoepitelioma benigno e um tricoepitelioma maligno. Em dois casos, os nódulos não foram removidos com margem cirúrgica completa. Desta forma, conclui-se que nas neoplasias benignas de folículo piloso, o número das regiões organizadoras de nucléolo e da expressão de Ki-67 foram significativamente menores que em neoplasias malignas. Além disto, sugere-se que a margem cirúrgica completa está mais associada à recorrência dos tumores que as regiões organizadoras de nucléolo, a expressão de Ki-67 e o índice mitótico