Effects of photoperiod on nutrient digestibility, hair follicle activity and cashmere quality in Inner Mongolia white cashmere goats.

Chong Zhi Zhang,Lu Jin,Chun Hua Zhang,Sheng Li Li,Hai Zhou Sun,Dan Sang,Marco Antonini,Cun Fa Zhao

doi:10.5713/ajas.18.0154

Abstract

ObjectiveThis study investigated the effects of photoperiod on nutrient digestibility, hair follicle (HF) activity and cashmere quality in Inner Mongolia white cashmere goats.MethodsTwenty-four female (non-pregnant) Inner Mongolia white cashmere goats aged 1 to 1.5 years old with similar live weights (mean, 20.36±2.63 kg) were randomly allocated into two groups: a natural daily photoperiod group (NDPP group:10 to 16 h light, n = 12) and a short daily photoperiod group (SDPP group: 7 h light:17 h dark, n = 12). All the goats were housed in individual pens and fed the same diets from May 15 to October 15, 2015. The digestibility of crude protein (CP), dry matter (DM), and neutral detergent fiber (NDF) were measured in different months, along with secondary hair follicle (SHF) activity, concentration of melatonin (MEL), and cashmere quality.ResultsAlthough there was no significant difference in the live weights of goats between the SDPP and NDPP groups (p>0.05), the CP digestibility of goats in the SDPP group was significantly increased compared to the NDPP group in July, September, and October (p<0.05). For the DM and NDF digestibility of goats, a significant increase (p<0.05) was found during in September in the SDPP group. Furthermore, compared to the NDPP group, the SHF activity in July, the MEL concentration in July, and the cashmere fiber length and fiber weight in October were significantly increased in the SDPP group (p<0.05).ConclusionThe cashmere production of Inner Mongolia white cashmere goats was increased without obvious deleterious effects on the cashmere fibers in the SDPP group (metabolizable energy, 8.34 MJ/kg; CP, 11.16%; short daily photoperiod, 7 h light:17 h dark).

Highlights

As a dynamic mini-organ, the skin hair follicle (HF) undergoes periodic transformations throughout its lifetime
The HFs in cashmere goats are divided into primary hair follicles (PHFs) and secondary hair follicles (SHFs); the cashmere with economic value is produced by SHFs, which are different from PHFs in both morphogenesis and function [1]
In order to explore the mechanism of cashmere growth underlying HF cycling and the fiber growth potential in cashmere goats, we investigated the effects of photoperiod on nutrient digestibility, HF activity, and cashmere quality in Inner Mongolia white cashmere goats

Summary

Introduction

As a dynamic mini-organ, the skin hair follicle (HF) undergoes periodic transformations throughout its lifetime. The cashmere exhibits a seasonal pattern arising from circannual changes in the natural photoperiod, and the number, function, and activity of the SHFs control the cashmere growth [7,8]. The secretion of MEL in cashmere goats shows distinct cyclical changes with photoperiod, and this cycle is consistent with the growth cycle of cashmere. Recent studies indicate that the yield, diameter (diam.), length of the cashmere fiber, regularity of methane (CH4), carbon dioxide (CO2), and ammonia (NH3) gases concentration are changed significantly [14,21], and the HFs can be induced to enter the full anagen phase early [5] by activating these periodic key regulators and extending the SHFs full-anagen phase via a short daily photoperiod [6]. In order to explore the mechanism of cashmere growth underlying HF cycling and the fiber growth potential in cashmere goats, we investigated the effects of photoperiod on nutrient digestibility, HF activity, and cashmere quality in Inner Mongolia white cashmere goats

Methods

Results

Discussion

Conclusion