RESUMEN
Internal parasites are a significant determinant of the productivity of ruminant species in the tropics. Provision of anthelmintics has become a predominant part of animal health interventions in emergency drought responses, aiming to maintain the food conversion efficiency of livestock when pasture is scarce. This study aimed to assess the owner-perceived impact of anthelmintic provision on the health and productivity of small ruminants in the drought-prone counties of Isiolo and Marsabit, northern Kenya. Participatory approaches were used to retrospectively measure differences in key indicators of livestock output before and after anthelmintic administration. Results showed that there was no perceived impact of anthelmintic administration during droughts on small ruminant health and productivity, but some benefit of anthelmintic administration during rainy season was perceived. The study also provided some evidence of potential differences in the epidemiology of internal parasites between the counties. These findings may be utilised to inform future livestock intervention programmes in drought-prone areas.
Asunto(s)
Crianza de Animales Domésticos , Infecciones por Nematodos/veterinaria , Rumiantes/fisiología , Animales , Antihelmínticos/uso terapéutico , Sequías , Urgencias Médicas/veterinaria , Femenino , Humanos , Kenia/epidemiología , Masculino , Infecciones por Nematodos/epidemiología , Infecciones por Nematodos/prevención & control , Rumiantes/parasitología , Encuestas y CuestionariosRESUMEN
In the dog CL are the only source of the progesterone in cyclic and pregnant animals. From a high expression of cyclooxygenase 2 (Cox2) at the beginning of the dioestrus and a low one at the end it was suggested that prostanoids may play a role in the formation of the CL. This led to the hypothesis that also in the dog PGE2 of luteal origin might act as paracrine/autocrine factor. Hence, expression of the prostaglandin E2 synthase (PGES) and its receptors (EP2 and EP4) was determined during the course of dioestrus in canine CL from days 5, 15, 25, 35, 45, 65 after ovulation, following cloning of PGES using SMART RACE PCR, which revealed a high homology (82-94%) with other species. Real Time (TaqMan) PCR showed a high PGES and EP2 expression in the early CL-phase with a significant decrease thereafter. EP4 revealed a constant expression pattern throughout the life span of the CL. In situ hybridization co-localized PGES, EP2 and EP4 in the cytoplasm of the luteal cells only. In conclusion, our data suggest that in the dog PGE2 of luteal origin acts by autocrine mechanism as a luteotropic factor through its EP2 and EP4 receptors during the phase of CL-formation.
Asunto(s)
Cuerpo Lúteo/fisiología , Diestro/fisiología , Oxidorreductasas Intramoleculares/genética , Receptores de Prostaglandina E/genética , Secuencia de Aminoácidos , Animales , Secuencia de Bases , Clonación Molecular , Cuerpo Lúteo/enzimología , Cartilla de ADN , ADN Complementario/genética , Perros , Femenino , Amplificación de Genes , Expresión Génica , Datos de Secuencia Molecular , Ovulación/fisiología , Prostaglandina-E Sintasas , Subtipo EP2 de Receptores de Prostaglandina E , Subtipo EP4 de Receptores de Prostaglandina E , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Factores de TiempoRESUMEN
In the dog luteolysis is not affected by hysterectomy. This observation led to the hypothesis that paracrine/autocrine rather than endocrine mechanisms of PGF2alpha are responsible for luteal regression in the dioestric bitch. The present experiments tested for the capacity of canine CL to produce and respond to PGF2alpha by qualitatively and quantitatively determining the expressions of PGFS, the enzyme converting PGH2 into PGF2alpha, and the PGF2alpha-receptor (FP) in CL of non-pregnant dogs during dioestrus. Canine PGFS and FP were isolated and cloned; both genes show a high homology (82-94%) when compared to those of other species. Relatively weak FP mRNA expression was detected on day 5 of dioestrus. It had increased by day 25 and remained constant thereafter. In situ hybridization (ISH) localized FP solely to the cytoplasm of the luteal cells, suggesting that these cells are the only luteal targets of PGF2alpha in this species. Only negative results were obtained for the expression of PGFS in canine CL by routine qualitative RT-PCR. When Real Time (TaqMan) PCR was applied, repetitively more negative than positive results were obtained at all timepoints. Any positive measurements observed at any point were neither repeatable nor related to the stage of dioestrus. This led us to conclude that expression of PGFS is either absent or present at very low level only. These data suggest that luteal regression in non-pregnant bitches is not modulated by PGF2alpha. However, the FP seems to be constitutionally expressed, explaining the receptivity of canine CL to exogenous PGF2alpha.