Horn growth patterns of Nubian ibex from the Sinai, Egypt

Documenting patterns of horn growth and horn-age relationships of Nubian ibex (Capra nubiana) can contribute to a more comprehensive understanding of their natural history, horn development in ibex in general, and future conservation of the species. Our specific objectives included (1) documenting age-horn growth patterns; (2) contrasting horn growth patterns of Nubian ibex with other ibex species; and (3) determining whether horn development accurately reflects age of Nubian ibex in Sinai, Egypt. As expected, all male and female horn measurements had significant relationships with age. Horn growth in males started plateauing at ca. age 7–8, whereas female horn growth started plateauing at ca. age 4–6. The extremely arid environment of Nubian ibex in the Sinai may account for the slowing of horn growth at a younger age than seen in populations of some other ibex species. We found a significant relationship between the number of horn ridges and age, indicating that counting horn ridges provides a viable method of aging males to within ±1 y. Thus counting horn ridges may be a useful and non-invasive method to determine age or age class, which can further our understanding of age structure, the natural history, and management of Nubian ibex populations.

Genetical control of 2D pattern and depth of the primordial furrow that prefigures 3D shape of the rhinoceros beetle horn

The head horn of the Asian rhinoceros beetle develops as an extensively folded primordium before unfurling into its final 3D shape at the pupal molt. The information of the final 3D structure of the beetle horn is prefigured in the folding pattern of the developing primordium. However, the developmental mechanism underlying epithelial folding of the primordium is unknown. In this study, we addressed this gap in our understanding of the developmental patterning of the 3D horn shape of beetles by focusing on the formation of furrows at the surface of the primordium that become the bifurcated 3D shape of the horn. By gene knockdown analysis via RNAi, we found that knockdown of the gene Notch disturbed overall horn primordial furrow depth without affecting the 2D furrow pattern. In contrast, knockdown of CyclinE altered 2D horn primordial furrow pattern without affecting furrow depth. Our results show how the depth and 2D pattern of primordial surface furrows are regulated at least partially independently during beetle horn development, and how both can alter the final 3D shape of the horn.

Clove Oil Delays Rather Than Prevents Scur/Horn Growth in Dairy Cattle

The objective of this study was to evaluate if administration of clove oil prevents scur/horn growth in dairy cattle long term. At approximately 4 days of age, calves had one of four treatments assigned to each horn bud: (1) clove oil administered subcutaneously under the horn bud (CLOV, n = 132); (2) cautery disbudded and the horn bud removed (BUDOFF, n = 126); (3) cautery disbudded and the horn bud tissue left intact (BUDON, n = 129); (4) a liquid nitrogen filled probe applied to the horn bud area (CRYO, n = 131). At approximately 16 months of age, all cattle were checked for scur or horn development. A sub-set of scurs/horns from the CLOV cattle were removed to evaluate tissue and structural development. In total, 5% of CLOV buds developed into horns and 63% into scurs; 10% of the scurs looked like normally developed horns but they were not attached to the skull. Cautery disbudding prevented scur and horn development in cattle when the horn bud tissue was removed, but some scur growth was observed in the BUDON treatment. CRYO was 100% ineffective at preventing scur/horn growth. Injecting clove oil under the horn bud appeared to delay horn development, but not prevent it, when administered to 4 day old dairy calves.