Melatonin implantation from winter solstice could extend the cashmere growth phase effectively

Effects of Heat Stress on Goat Production and Mitigating Strategies: A Review

Goats, versatile creatures selectively bred for various purposes, have become pivotal in shaping the socioeconomic landscape, particularly in rural and economically challenged areas. Their remarkable ability to withstand and adapt to extreme heat has proven invaluable, allowing them to flourish and reproduce in even the harshest climates on Earth. Goat farming has emerged as a reliable and sustainable solution for securing food resources. However, despite its significance, the goat-producing industry has received less attention than other ruminants. Despite goats' inherent resilience to heat, their productivity and reproductive performance suffer under high ambient temperatures, leading to heat stress. This presents a significant challenge for goat production, necessitating a comprehensive multidisciplinary approach to mitigating the adverse effects of heat stress. This review aims to explore the diverse impacts of heat stress on goats and propose effective measures to address the sector's challenges. By understanding and addressing these issues, we can enhance the resilience and sustainability of goat farming, ensuring its continued contribution to food security and socioeconomic development.

Association analysis for SNPs of LIPE and ITGB4 genes with cashmere production performance, body measurement traits and milk production traits in Liaoning cashmere goats

Liaoning cashmere goat (LCG) is one of the excellent cashmere goat breeds in China. Because of its larger size, better cashmere, and better cashmere production performance, people pay special attention to it. This article mainly studied the relationship between SNP loci of LIPE gene and ITGB4 gene and milk production, cashmere production and body measurement traits of LCGs. We further identified potential SNP loci by PCR-Seq polymorphism detection and gene sequence comparison of LIPE and ITGB4 genes. Further, we use SPSS and SHEsis software to analyze their relationship to production performance. The consequence indicated that CC genotype of LIPE gene T16409C locus was dominant genotype in milk production and cashmere production, while CT genotype of LIPE gene T16409C locus was dominant in body size. The CT genotype of C168T locus of ITGB4 gene is the dominant genotype of body type and cashmere production, while the dominant genotype of milk production is TT genotype. Through joint analysis, in haploid combinations, H1H2:CCCT is the dominant haplotype combination in cashmere fineness. H3H4:TTCT is a dominant haplotype combination of milk production traits and body measurement traits. These dominant genotypes can provide a reliable basis for the study of production performance of LCG.

Melatonin regulates the periodic growth of secondary hair follicles through the nuclear receptor RORα

Cashmere is the fine bottom hair produced by the secondary hair follicles of the skin. This hair is economically important. Previous studies by our research group have shown that exogenous melatonin (MT) can regulate the periodic growth of secondary hair follicles, induce the secondary development of villi, and alter the expression of some genes related to hair follicle development. Few studies on the regulation of villus growth by MT binding receptors have been published. In this study, MT was implanted subcutaneously behind the ear of Inner Mongolia cashmere goats. RT-qPCR, in situ hybridization, Western blot analysis, immunofluorescence and RNAi techniques were used to investigate the receptors and functions of MT in regulating the development of secondary hair follicles in Inner Mongolia cashmere goats. The results showed that MT binds to the nuclear receptor RORα on dermal papilla stimulates hair follicle development and promotes villus growth. The RORα mRNA expression in the skin of Inner Mongolia cashmere goats was periodic and showed a trend of first increasing and then decreasing. The expression began to increase in February, peaked in April, and reached the lowest level in May. RORα significantly affected the mRNA expression of β-catenin gene, a key gene in hair follicle development, in the presence of MT. It will lay a solid molecular foundation for further research on the regulation mechanism between MT receptor and villus growth and development and to achieve artificial regulation of villus growth time and yield to improve the effect of villus production.

Melatonin promotes the development of the secondary hair follicles by regulating circMPP5

BACKGROUND

The quality and yield of cashmere fibre are closely related to the differentiation and development of secondary hair follicles in the skin of cashmere goats. The higher the density of secondary hair follicles, the higher the quality and yield of cashmere from the fleece. Development of secondary hair follicles commences in the embryonic stage of life and is completed 6 months after birth. Preliminary experimental results from our laboratory showed that melatonin (MT) treatment of goat kids after their birth could increase the density of secondary hair follicles and, thus, improve the subsequent yield and quality of cashmere. These changes in the secondary hair follicles resulted from increases in levels of antioxidant and expression of anti-apoptotic protein, and from a reduction in apoptosis. The present study was conducted to explore the molecular mechanism of MT-induced secondary hair follicle differentiation and development by using whole-genome analysis.

RESULTS

MT had no adverse effect on the growth performance of cashmere kids but significantly improved the character of the secondary hair follicles and the quality of cashmere, and this dominant effect continued to the second year. Melatonin promotes the proliferation of secondary hair follicle cells at an early age. The formation of secondary hair follicles in the MT group was earlier than that in the control group in the second year. The genome-wide data results involved KEGG analysis of 1044 DEmRNAs, 91 DElncRNAs, 1054 DEcircRNAs, and 61 DEmiRNAs which revealed that the mitogen-activated protein kinase (MAPK) signaling pathway is involved in the development of secondary hair follicles, with key genes (FGF2, FGF21, FGFR3, MAPK3 (ERK1)) being up-regulated and expressed. We also found that the circMPP5 could sponged miR-211 and regulate the expression of MAPK3.

CONCLUSIONS

We conclude that MT achieves its effects by regulating the MAPK pathway through the circMPP5 sponged the miR-211, regulating the expression of MAPK3, to induce the differentiation and proliferation of secondary hair follicle cells. In addition there is up-regulation of expression of the anti-apoptotic protein causing reduced apoptosis of hair follicle cells. Collectively, these events increase the numbers of secondary hair follicles, thus improving the production of cashmere from these goats.

Effect of Controlling Light on Cashmere Growth and Harmful Gas Parameters in Shanbei White Cashmere Goats

The quality and yield of cashmere closely affect the economic benefits of cashmere goat farming. Studies have shown that controlling light can have an important impact on cashmere but can also affect the concentration of harmful gases. In order to explore the impact of a short photoperiod on the growth of cashmere and harmful gases in goat houses, 130 female (non-pregnant) Shanbei white cashmere goats, aged 4–5 years with similar body weights, were randomly divided into a control group and a treatment group, with 65 goats in each group. The dietary nutrition levels of the experimental goats were the same, and completely natural light was used in the control group; the light control group received light for 7 h every day (9:30–16:30), and the rest of the time (16:30–9:30 the next day) they did not receive light. The light control treatment was carried out in a control house, and the gas content was analyzed. It was found that a shortened period of light exposure could increase the annual average cashmere production by 34.5%. The content of each gas has a certain functional relationship with the measurement time period, but at the same time, we found that the content of NH3 also changes seasonally. In summary, the use of shortened light periods when raising cashmere goats can significantly increase cashmere production and quality, but at the same time, it will increase the concentration of harmful gases in the goat barn, and ventilation should be increased to ensure the health of the goats and the air quality in the barn.

Inhibition of prolactin promotes secondary skin follicle activation in cashmere goats

The aim of this study was to investigate the involvement of prolactin (PRL) on development of secondary skin follicles in cashmere goats. Goats were randomly assigned to either a bromocriptine treatment or control group. Samples of cashmere fiber, blood, and skin were collected from all goats after 1 mo. The results indicated that the length, growth rate, and diameter of fibers were not influenced (P > 0.05) by the inhibition of PRL resulting from the treatment with bromocriptine. There was a tendency for increases in total follicle number, primary and secondary follicle numbers, and in the ratio of secondary to primary follicles following treatment with bromocriptine, but these differences were not significant (P > 0.05). The percentage of active secondary follicles in anagen was increased (P < 0.05) in the bromocriptine-treated goats, but there was no effect of treatment on the percentage of active primary follicles. Bromocriptine decreased (P < 0.05) circulating concentrations of PRL and Insulin-like growth factor 1 (IGF1) and increased (P < 0.05) those of melatonin (MT), but there was no effect of this treatment on the serum concentrations of cortisol, growth hormone, tetraiodothyronine, and triiodothyronine. In bromocriptine-treated goats, mRNA expressions of PRL and MT membrane receptor 1a (MTNR1a) were decreased (P < 0.05) and mRNA expression of MT nuclear receptor (RORα) was increased (P < 0.05), but there was no effect of the treatment on expression of long PRL receptor, short PRL receptor, MT membrane receptor 1b and IGF1. It is concluded that inhibition of PRL promotes secondary hair follicle development in the anagen phase, possibly by downregulating MTNR1a and up-regulating RORα gene expression in the skin.

Effects of melatonin administration to cashmere goats on cashmere production and hair follicle characteristics in two consecutive cashmere growth cycles

The objective of the study was to determine the long-term effects of melatonin treatment on cashmere production and hair follicle populations in cashmere goats and their activity in two consecutive cashmere growth cycles. Twenty-four female Inner Mongolian Cashmere goats were randomly allocated to two groups (n = 12), one of which received melatonin implants, the other being an untreated control group. Melatonin implants were subcutaneously inserted behind the ear at a dose of 2 mg/kg live weight on two occasions -April 30 and June 30, 2016. Hair samples were collected by combing in April of 2017 and 2018, and the weight, staple length, and diameter of the cashmere fibers were measured. Blood and skin samples were collected monthly between April and September 2016, and in April and September in 2017 for the analysis of melatonin concentration and the characteristics of secondary hair follicle populations, respectively. The results indicated that serum melatonin concentration in the treated goats was elevated (P < 0.05) relative to that of the control group, but only during the first growth cycle. Melatonin treatment of cashmere goats in one cashmere growth cycle increased the weight, staple length, and density (all P < 0.05) of the cashmere fibers and decreased fiber diameter (P < 0.01), but did not affect the characteristics of cashmere production in the subsequent annual cycle. Melatonin treatment had no effect on the population of skin secondary hair follicles for two consecutive cycles. However, in the first growth cycle after treatment, it advanced the onset of activity of skin secondary hair follicles by 2 mo (P < 0.05), and it increased the number of follicles that were active (P < 0.05). In summary, the melatonin treatment of cashmere goats in one cashmere growth cycle improved cashmere production for that cycle only, with no residual effects on the subsequent cycle, a technique acceptable to the cashmere goat industry. The enhancement of cashmere production after the treatment of goats with melatonin appears to involve the acceleration of the annual regeneration of skin secondary hair follicles and increased population of active secondary hair follicles in the skin of cashmere goats.

Effects of melatonin implantation on carcass characteristics, meat quality and tissue levels of melatonin and prolactin in Inner Mongolian cashmere goats

Background

Implantation of goats with melatonin can induce cashmere growth and significantly increase cashmere production performance. However, the impact of melatonin implantation on the carcass characteristics, meat quality and related hormone levels in muscle and viscera of cashmere goats has not been studied. This experiment was conducted to determine the effects of melatonin implantation of cashmere goats during the non-growing period on meat quality and related hormone levels in the tissues. It aimed to provide a theoretical basis for the practical application of melatonin in cashmere goat production systems.

Results

Melatonin implantation (2 mg/kg live weight) had no influence (P > 0.05) on daily weight gain, carcass weight, dressing percentage, loin muscle area, or the pH, moisture level, crude fat (except for Gluteus muscle) and amino acid content of muscles of cashmere goats. After implantation for 1 month, shear force of Longissimus dorsi and water loss rate of Longissimus dorsi and Biceps femoris of cashmere goats were increased (P < 0.05), whereas the cooking yield of Gluteus muscle was reduced (P < 0.05). The melatonin treatment decreased (P < 0.05) muscle crude protein, Gluteus muscle crude fat and ∑n-3PUFA content and decreased (P < 0.05) ∑n-6PUFA content. However, after 2 months of implantation most of these effects had resolved. Melatonin implantation had no effect (P > 0.05) on the melatonin or prolactin contents of kidney, heart, spleen, liver, Longissimus dorsi, Biceps femoris and Gluteus muscles. Melatonin content of lung tissue was lowered (P < 0.05) and that of prolactin was elevated (P < 0.05) by the melatonin implantation.

Conclusion

This study has shown little impact of melatonin implantation of cashmere goats on carcass quality. A few meat quality indices i.e., shear force, water loss rate, ∑n-3PUFA, ∑n-6PUFA, and crude protein content of Longissimus dorsi; water loss rate, cooking yield and crude protein content of Biceps femoris; ether extract, crude protein content of Gluteus; were affected briefly (at 1 month of implantation) but these effects were not evident after 2 months of implantation. There was little effect of the melatonin treatments on tissue levels of melatonin or prolactin except in lung.

The induction of cashmere shedding via cyclophosphamide injection

The aim of this study was to investigate the effects of cyclophosphamide (CPA) on cashmere shedding in cashmere goats. Thirty-two castrated Liaoning cashmere goats were randomly allotted to four groups, with eight replicates in each group. The four groups were injected intravenously with CPA doses of 0, 15, 20 and 25 mg/kg body weight, respectively. Feed intake, body weight, body temperature, and sphygmus were recorded and the erythrocyte count, leukocyte count, hemoglobin content, and cashmere yield and length were determined. CPA has no significant effect on feed intake, body weight, body temperature, or sphygmus of cashmere goats. It was found that CPA significantly decreased the erythrocyte count and hemoglobin content in cashmere goats on the days immediately following injection, but the effects on erythrocytes diminished within 6 days, with hemoglobin content returning to normal within 10 days. Cashmere fiber began to shed on about day 10 after injection with CPA. CPA had no significant effect on cashmere length but significantly increased cashmere yield. The results indicate that CPA can induce cashmere shedding and achieve the purpose of concentrated defleecing. A dose of 20 mg/kg body weight is preferable for hair removal and regrowth in cashmere goats.

Effects of melatonin implantation on cashmere growth, hormone concentrations and cashmere yield in cashmere-perennial-type Liaoning cashmere goats

The aim of the present study was to investigate the effects of melatonin implants on cashmere growth, the concentrations of plasma melatonin and prolactin and the total cashmere yield in cashmere-perennial-type Liaoning cashmere goats. Twenty female goats were assigned to two treatments (n = 10) including a control and a treatment in which melatonin (2 mg/kg bodyweight) was implanted in March and May, respectively. The experiment lasted for 153 days. Fibre samples were collected in July, August and April the following year (before cashmere harvest). Blood samples were taken monthly from March to August. Cashmere yield was recorded after harvest. In melatonin-treated goats, cashmere length and cashmere growth rate from April to July were significantly increased (P < 0.05), but no influence was observed (P > 0.05) in August. Implantation of melatonin significantly increased plasma melatonin concentrations (P < 0.05) and decreased prolactin concentrations from April to July compared with the control group (P < 0.05), but no difference was observed in August (P > 0.05). Administration of melatonin increased the cashmere yield by 6.2% and the maximum cashmere length by 8.4%, but the differences were not significant (P > 0.05). Moreover, the cashmere fibre diameter was not influenced by melatonin implantation (P > 0.05). The results also indicated that plasma melatonin concentrations were correlated with plasma prolactin in the regulation of cashmere growth. Implantation of melatonin was an effective way to promote cashmere growth, and administration during the cashmere slow-growing period improved cashmere production without changing cashmere fibre diameter in cashmere-perennial-type Liaoning cashmere goats.

Melatonin and cashmere growth in Inner Mongolian cashmere goats

The aim of the study was to investigate the effects of melatonin implants on cashmere growth and productive performance of cashmere goats. A total of thirty female goats were assigned to one of three treatments (n = 10), including control and two treatments where melatonin [2 mg kg−1 body weight (BW)] was implanted either in April and June or in June. Compared with the control, implantation in April and June increased cashmere yield and maximum cashmere length by 20.3% and 15.7%, respectively (P < 0.01), with an average initiation date of 22 May 2013 and cessation date of 26 Mar. 2014. In contrast, no cashmere growth was observed in control goats until 19 June 2013 and the growth ceased on 3 Apr. 2014. Melatonin only implanted in June had no effect on cashmere yield and maximum cashmere length, with an average initiation date of 5 June 2013 and cessation date of 27 Mar. 2014. Cashmere growth rate, cashmere fiber diameter, the final BW, and average daily gain were not influenced by melatonin implantation. Results suggested that melatonin implantation during the cashmere nongrowing period is an effective way to stimulate cashmere growth and extend the cashmere growth phase with April and June identified as the most appropriate time for implantation.

Effects of melatonin implantation on cashmere yield, fibre characteristics, duration of cashmere growth as well as growth and reproductive performance of Inner Mongolian cashmere goats

Background

Exogenous melatonin could induce cashmere growth. However, induced growth of cashmere fleece by melatonin implants cannot be combined with the typical growth, resulting in earlier shedding followed by another cycle of cashmere growth. To address this issue, we examine the effects on the cashmere yield, fibre characteristics, and the growth and reproductive performance of cashmere goats of planned administration of melatonin.

Methods

Eighteen half-sib, female goats were assigned to two treatments (n = 9) including a control and a treatment where melatonin (2 mg/kg BW) was implanted at the end of April and end of June. Cashmere growth and shedding were observed for approximately 1 year following implantation. Fibre samples were collected monthly to determine cumulative cashmere length. Initiation and cessation dates for cashmere growth as well as the rate of cashmere growth were calculated. Cashmere yield, weight gain of dam, kidding date, litter size, and birth weight were also recorded.

Results

Melatonin implantation increased cashmere yield by 34.5 % (control 553.7 g vs. melatonin 745.0 g; P < 0.01), cashmere length by 21.3 % (control 95.2 mm vs. melatonin 115.4 mm; P < 0.01), and decreased fibre diameter by 4.4 % (control 14.6 μm vs. melatonin 14.0 μm; P < 0.03). In melatonin-treated goats, the average initiation date was earlier than in control goats (May 18, 2013 vs. July 2, 2013; P < 0.01) but there was a similar cessation date (March 22, 2014 vs. March 27, 2014). Consequently, the duration of cashmere growth was longer in melatonin-treated goats than in control goats (307 vs.270 days; P < 0.01). The final BW, average daily gain, kidding date, litter size, and birth weight were not influenced by melatonin implantation.

Conclusions

These data indicate that melatonin implantation (2 mg/kg BW) on two occasions (late April and June) increased cashmere yield by combining the induced growth of cashmere fleece with the typical growth and decreased the fibre diameter without changing dam growth rate or reproductive performance.