Abstract

Two groups of 1-month-old pre-ruminant lambs of similar mean liveweights were fed identical liquid milk-replacer diets except that the zinc contents were either 5 micrograms (deficient diet) or 32 micrograms per gram of dry matter (control diet). These diets were fed for 4 weeks, after which all the lambs received the control diet for 2 weeks. In the lambs fed the deficient diet plasma zinc concentration decreased markedly during the first 2 weeks and skin lesions developed around their mouths. Autophagic vacuoles also developed in most follicle bulbs along with a variety of defects in the wool fibres and progressive inhibition of wool growth. Food intake and liveweight increase were not significantly depressed until the third and fourth weeks of feeding the deficient diet. During this period the wool was shed from the zinc-deficient lambs as a result of the fibres being degraded and distorted within thickened outer root sheaths in the distal (upper) parts of the follicles. In addition, the epidermis of the wool-bearing skin became slightly acanthotic and hyperkeratotic, although not parakeratotic. When the deficient lambs were fed the control diet for 2 weeks, their food intake, liveweight gain and plasma zinc concentration increased to almost those of the control lambs, but their rate of wool growth was still low and the epidermis had not returned to normal. Compared with previous studies the findings of this study suggest that pre-ruminant lambs may be more susceptible to the effects of zinc deficiency than ruminant lambs.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.