Perinatal lamb mortality in the central sierra of Peru

Perinatal lamb mortality is one of the major factors in impairment of productivity on sheep raising enterprises around the world. In this study, perinatal mortality on one of the largest sheep raising enterprises in Peru was measured over a 10-year period. Between 1971 and 1980, a total of 603 694 lamb births was recorded. Mortality during the first 3 days of life was 36.94/1000 births and for the period from 4 to 30 days mortality was 5.87/1000.

Non-infectious conditions predominated as causes of mortality. The weak lamb syndrome, accidents, injuries and starvation were the leading causes of mortality. Diseases of infectious etiology were second in importance, but may have been under-reported. Variation in mortality between years, did not appear to affect the patterns of mortality by cause.

Approximately 86% of mortality occurred in the first 3 days of life. During this period, nutritional, environmental and management factors resulting in weak lambs and starvation accounted for approximately a third of total mortality. Infections (22%), accidents (22%), and stillbirths (16%) followed in order of importance. During the remainder of the first month of life, deaths from infections predominated, accounting for 60% of mortality from 4 to 30 days.     

miRNA and piRNA expression profiles of breeder cock testes detected by next‐generation sequencing

miRNAs are small non‐coding regulatory RNAs that play key roles in diverse biological processes. In this study, we used the Solexa sequencing technique to profile miRNAs in breeder cock testes to illustrate their functions. A total of 663 co‐expressed miRNAs and 3,180 co‐expressed piRNAs were detected in three libraries. Based on Mir‐X^? miRNA qRT‐PCR, three miRNAs representing low, medium and high expression levels according to the sequencing results were selected randomly to validate the miRNAs' expression profiles. Results suggested that the miRNA expression profiles data could represent actual miRNA expression levels. Moreover, target genes prediction of the co‐expressed miRNAs and further Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed, which revealed that some candidate miRNAs were involved in the regulation of the spermatogenesis process, spermatozoa function and testicular metabolism. In conclusion, we provided a useful resource for further elucidation of the miRNAs' regulatory role in spermatogenesis, contributing to a preliminary database for functional and molecular mechanistic studies in testicular metabolism, spermatogenesis and other testes functions.