Effects of Zinc Deficiency on the Wool Growth, Skin and Wool Follicles of Pre-ruminant Lambs

Abstract

Two groups of I-month-old pre-ruminant lambs of similar mean liveweights were fed identical liquid milkreplacer diets except that the zinc contents were either 5 p.g (deficient diet) or 32 p.g 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.

The effect of zinc deficiency on wool growth and skin and wool follicle histology of male Merino lambs

“…Histological lesions in the skin and wool follicle of sheep fed on the diet containing 4 mg Zn/kg were similar to, but less extensive than, those reported in pre-ruminant lambs fed on a milk diet containing 3 mg Zn/kg dry matter (Masters et al 1985). In the current experiment skin from the Zn-deficient sheep contained apoptotic bodies in follicle bulbs, impaired keratinization of fibres with retained cell nuclei and fibre distortion in the distal parts of some follicles.…”

“…A severe dietary Zn deficiency (less than 3 mg Zn/kg diet) causes cessation of wool growth in sheep (Ott et al 1964(Ott et al , 1965Mills et al 1967;Underwood & Somers, 1969;Masters et al 1985), yet the minimum requirement of Zn for wool growth has not been established. Masters (1984) showed that Merino wethers fed on a diet containing 8.8 mg Zn/kg grew less wool than sheep fed on diets containing 26.5 mg Zn/kg.…”

Skin diseases in the alpaca (Vicugna pacos): a literature review and retrospective analysis of 68 cases (Cornell University 1997–2006)

“…This is unlike the diffuse parakeratotic hyperkeratosis classically reported in swine, 67 cattle 68 and dogs. 69 In sheep [70][71][72] and goats, 73,74 however, the keratinization abnormality in zinc-responsive dermatoses has been reported to be parakeratotic, orthokeratotic or a combination of both of these.…”

Pregnancy rate in ewes injected with zinc oxide during an estrus synchronization protocol

“…Zinc is an essential mineral to sustain life and one of the most abundant trace minerals inside the animal's organism, but its endogenous storage is low and it must be provided to animals by feed or mineral supplementation (Mir et al, 2020;Swain et al, 2016). In the organism, zinc participates as enzymatic cofactor, regulates cell growth, immunity and reproductive function in mammals (Hill & Shannon, 2019;Nasiadek et al, 2020) whereas zinc body deficiency causes low productive (Masters et al, 1985) and reproductive performance (Tian & Diaz, 2012;Tian et al, 2014). Zinc can be administrated to animals orally or by injection.…”