Saanen Dairy Goats Research Articles

Specificity protein 1 regulates gene expression related to fatty acid metabolism in goat mammary epithelial cells.

Specificity protein 1 (SP1) is a ubiquitous transcription factor that plays an important role in controlling gene expression. Although important in mediating the function of various hormones, the role of SP1 in regulating milk fat formation remains unknown. To investigate the sequence and expression information, as well as its role in modulating lipid metabolism, we cloned SP1 gene from mammary gland of Xinong Saanen dairy goat. The full-length cDNA of the SP1 gene is 4376 bp including 103 bp of 5'UTR, 2358 bp of ORF (HM_236311) and 1915 bp of 3'UTR, which is predicted to encode a 786 amino acids polypeptide. Phylogenetic tree analysis showed that goat SP1 has the closest relationship with sheep, followed by bovines (bos taurus, odobenus and ceratotherium), pig, primates (pongo, gorilla, macaca and papio) and murine (rattus and mus), while the furthest relationship was with canis and otolemur. Expression was predominant in the lungs, small intestine, muscle, spleen, mammary gland and subcutaneous fat. There were no significant expression level differences between the mammary gland tissues collected at lactation and dry-off period. Overexpression of SP1 in goat mammary epithelial cells (GMECs) led to higher mRNA expression level of peroxisome proliferator-activated receptor-γ (PPARγ) and lower liver X receptor α (LXRα) mRNA level, both of which were crucial in regulating fatty acid metabolism, and correspondingly altered the expression of their downstream genes in GMECs. These results were further enhanced by the silencing of SP1. These findings suggest that SP1 may play an important role in fatty acid metabolism.

Effects of sucrose and sunflower oil addition to diet of Saanen dairy goats on performance and milk fatty acid profile

The current study was conducted to examine the effect of dietary sucrose with or without sunflower oil on dairy goat performance, ruminal fermentation and milk fatty acid (FA) profile. Sixteen Saanen goats were assigned to the experimental diets control (basal diet without added oil and sucrose (CON), the basal diet supplemented with sunflower oil (SO, 3.7% of diet DM), sucrose (SU, 5.2% of diet DM) and sunflower oil plus sucrose (SO+SU, 3.7% and 5.2% of diet DM, respectively). Sucrose and sunflower oil replaced barley grain in the diets. Milk production and composition were analyzed on days 18, 36 and 54 on treatments, and ruminal fermentation parameters and milk FA profile on days 18 and 54. Dry matter intake, milk fat, protein and lactose concentrations were not affected by treatments. The SU increased (P<0.1) milk yield compared with CON whereas the SU and SO led to higher (P<0.01) 4% fat-corrected milk yield. The SO and SU diets increased (P<0.1) the milk lactose yield more than the CON diet. We observed a higher (P<0.01) content of ruminal acetate in the CON diet, and also higher (P<0.05) valerate content with the SU and SO+SU diets compared with the CON diet. Feeding SU and SO+SU tended to decrease (P<0.05) ruminal pH, yet goats fed SU had the highest (P<0.01) ruminal propionate concentration. There was no effect of diet on ruminal butyrate, isovalerate and ammonia-N concentrations. The acetate:propionate ratio substantially decreased (P<0.05) with the SU compared with the CON and SO+SU, and did not change with SO diet. Feeding sunflower oil increased (P<0.01) plasma triglyceride and cholesterol concentrations compared with feeding the CON and SU diets. The majority of fatty acids measured were not affected by inclusion of sucrose compared with the CON diet. The SO and SO+SU diets increased the proportion of total trans-C18:1, total CLA, and C18 family in milk fat compared to CON or SU diets. The current study implies that replacing barley grain with sucrose may improve milk yield and modify ruminal fermentation pattern in dairy goats. Moreover, sucrose did no alter ruminal fatty acid biohydrogenation pathways and following milk fatty acid composition when goats were fed with a combination of unsaturated fat and sugar.

Lipoprotein lipase, tissue expression and effects on genes related to fatty acid synthesis in goat mammary epithelial cells.

Lipoprotein lipase (LPL) serves as a central factor in hydrolysis of triacylglycerol and uptake of free fatty acids from the plasma. However, there are limited data concerning the action of LPL on the regulation of milk fat synthesis in goat mammary gland. In this investigation, we describe the cloning and sequencing of the LPL gene from Xinong Saanen dairy goat mammary gland, along with a study of its phylogenetic relationships. Sequence analysis showed that goat LPL shares similarities with other species including sheep, bovine, human and mouse. LPL mRNA expression in various tissues determined by RT-qPCR revealed the highest expression in white adipose tissue, with lower expression in heart, lung, spleen, rumen, small intestine, mammary gland, and kidney. Expression was almost undetectable in liver and muscle. The expression profiles of LPL gene in mammary gland at early, peak, mid, late lactation, and the dry period were also measured. Compared with the dry period, LPL mRNA expression was markedly greater at early lactation. However, compared with early lactation, the expression was lower at peak lactation and mid lactation. Despite those differences, LPL mRNA expression was still greater at peak, mid, and late lactation compared with the dry period. Using goat mammary epithelial cells (GMEC), the in vitro knockdown of LPL via shRNA or with Orlistat resulted in a similar degree of down-regulation of LPL (respectively). Furthermore, knockdown of LPL was associated with reduced mRNA expression of SREBF1, FASN, LIPE and PPARG but greater expression of FFAR3. There was no effect on ACACA expression. Orlistat decreased expression of LIPE, FASN, ACACA, and PPARG, and increased FFAR3 and SREBF1 expression. The pattern of LPL expression was similar to the changes in milk fat percentage in lactating goats. Taken together, results suggest that LPL may play a crucial role in fatty acid synthesis.

Parathyroid hormone-related protein overexpression protects goat mammary gland epithelial cells from calcium-sensing receptor activation-induced apoptosis.

Normal mammary gland epithelial cells and breast cancer cells express the calcium-sensing receptor (CaSR), which is the master regulator of systemic calcium metabolism. During lactation, activation of the CaSR in mammary epithelial cells downregulates parathyroid hormone-related protein (PTHrP) levels in milk and in the circulation, and increases calcium transport into milk. However, very little information is available on the role of CaSR in goat mammary gland epithelial cells (GMECs) apoptosis. In this investigation, the full-length cDNA of CaSR from Xinong Saanen dairy goats was cloned, which contains an open-reading frame of 3,258 bp encoding 1,085 amino acids with a predicted molecular weight of 121.0 kDa and an isoelectric point of 5.65. The amino acid sequence is highly homologous with sheep, and the goat CaSR gene is mapped to chromosome 1. Quantitative real-time PCR suggested that CaSR was predominantly expressed in the heart, kidney and mammary gland. Then, we found the stimulation of CaSR with its activator gadolinium chloride (GdCl3) contributed to increase CaSR mRNA levels in GMECs and simultaneously promoted cell apoptosis, and these effects were abrogated partially by NPS2390 which is an inhibitor of CaSR. We also demonstrated that Ca(2+) increased CaSR mRNA levels and induced GMECs apoptosis and restrained cell proliferation. In contrast, PTHrP overexpression protected GMECs from calcium-induced apoptosis, and promoted cell proliferation. In conclusion, these results suggest that PTHrP overexpression protects GMECs from CaSR activation-induced apoptosis.

Determination of the novel genetic variants of goat STAT5A gene and their effects on body measurement traits in two Chinese native breeds

Signal transducer and activator of transcription 5A (STAT5A), previously known as mammary gland factor (MGF), belongs to the prolactin/JAK2/STAT5 pathway, and plays an important role in growth and development, milking, and lipid accumulation in mammals. The aim of this study was to identify novel genetic variants of the goat STAT5A gene, as well as to test the possible effects of these variants on body measurement traits in the Xinong Saanen dairy goat (XNSN, milking breed) and the Hainan black goat (HNBG, meat breed) that thrive in Northwest China and Southeast China, respectively, which concurrently need improvement in terms of growth. Three novel single nucleotide polymorphisms (SNPs) (IVS1+254C>T, SNP1; Tyr90Tyr, SNP2; and IVS3+303T>C, SNP3) within the goat STAT5A gene were identified in intron 1, exon 2, and intron 3, respectively, as well as a documented SNP (Pro268Pro, SNP4) was also detected in exon 7. These SNPs were genotyped using the amplification created restriction site-polymerase chain reaction-restriction fragment length polymorphism (aCRS-PCR-RFLP) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods; their minor allelic frequencies varied from 0.079 (SNP4) to 0.372 (SNP2) in the HNBG breed as well as from 0 (SNP1) to 0.362 (SNP4) in the XNSN breed, respectively. The PIC values of these loci varied from 0 to 0.358. Haplotype analysis uncovered only 8 haplotypes; the major haplotypes were Hap1 (CCCC), Hap2 (CCTC), and Hap4 (CTTC). During linkage disequilibrium analysis, only SNP1 and SNP3 loci showed strong linkage (r2=0.999) in the HNBG breed. Statistical analyses indicated that only the known variant (SNP4, Pro268Pro) was significantly associated with body measurement traits in the two breeds when analyzed separately or in combination (P<0.05 or P<0.01), implying that this SNP significantly affected goat body measurement traits. Therefore, the STAT5A gene is a candidate gene affecting goat body measurement traits and could contribute to goat breeding improvement programs through marker-assisted selection (MAS).

CD49f-positive testicular cells in Saanen dairy goat were identified as spermatogonia-like cells by miRNA profiling analysis.

miRNAs, a type of small RNA, play critical roles in mammalian spermatogenesis. Spermatogonia are the foundation of spermatogenesis and are valuable for the study of spermatogenesis. However, the expression profiling of the miRNAs in spermatogonia of dairy goats remains unclear. CD49f has been one of the surface markers used for spermatogonia enrichment by magnetic activated cell sorting (MACS). Therefore, we used a CD49f microbead antibody to purify CD49f-positive and -negative cells of dairy goat testicular cells by MACS and then analysed the miRNA expression in these cells in depth using Illumina sequencing technology. The results of miRNA expression profiling in purified CD49f-positive and -negative testicular cells showed that 933 miRNAs were upregulated in CD49f-positive cells and 916 miRNAs were upregulated in CD49f-negative cells with a twofold increase, respectively; several miRNAs and marker genes specific for spermatogonial stem cells (SSCs) in testis had a higher expression level in CD49f-positive testicular cells, including miR-221, miR-23a, miR-29b, miR-24, miR-29a, miR-199b, miR-199a, miR-27a, and miR-21 and CD90, Gfra1, and Plzf. The bioinformatics analysis of differently expressed miRNAs indicated that the target genes of these miRNAs in CD49f-positive cells were involved in cell-cycle biological processes and the cell-cycle KEGG pathway. In conclusion, our comparative miRNAome data provide useful miRNA profiling data of dairy goat spermatogonia cells and suggest that CD49f could be used to enrich dairy goat spermatogonia-like cells, including SSCs.

Effects of pistachio by-products on digestibility, milk production, milk fatty acid profile and blood metabolites in Saanen dairy goats.

The objective of this study was to investigate the effects of pistachio by-products (PBP) on nutrient digestibility, blood metabolites and milk fatty acid (FA) profile in Saanen dairy goats. Nine multiparous lactating Saanen goats (on day 90 post-partum, 45±2/kg BW) were randomly assigned to a 3×3 Latin square design with three treatment diets: 1) control diet (alfalfa hay based), 2) 32% PBP and 3) 32% PBP+polyethylene glycol (PEG-4000; 1g/kg dry matter). Each period lasted 21days, including 14day for treatment adaptation and 7day for data collection. Pistachio by-products significantly decreased (p<0.01) crude protein (CP) digestibility compared with the control diet (64.4% vs. 58.7%), but PEG addition did not differ for CP digestibility of goats fed 32% PBP+PEG and those fed the two other diets. The digestibility of NDF tended (p=0.06) to decrease for goats fed PBP compared with those fed the control diet. Yields of milk and 4% fat-corrected milk were not affected by dietary treatments. Compared with the control diet, PBP supplementation appreciably changed the proportions of almost all the milk FA measured; the main effects were decreases (p<0.01) in FA from 8:0 to 16:0 and increases (p<0.01) proportions of cis-9, trans-11 18:2 and trans-11 18:1, monounsaturated FA, polyunsaturated FA and long-chain FA. The saturated FA, short-chain FA and medium-chain FA proportions were lower (p<0.01) in goats fed the two PBP supplemented diet than in those fed the control diet and PEG addition led to intermediate proportions of saturated FA, unsaturated and monounsaturated FA. Inclusion of PBP in the diet decreased (p<0.01) plasma concentrations of glucose and urea nitrogen compared with the control diet. It was concluded that PBP can be used as forage in the diet of dairy goats without interfering with milk yield. Inclusion of 32% PBP in the diet of dairy goats had beneficial effects on milk FA profile but PEG addition to PBP did not contribute to enhance further milk FA profile.

Closantel plasma and milk disposition in dairy goats: assessment of drug residues in cheese and ricotta.

Closantel (CLS) is currently used in programs for the strategic control of gastrointestinal nematodes. CLS is extralabel used in different dairy goat production systems. From available data in dairy cows, it can be concluded that residues of CLS persist in milk. The current work evaluated the concentration profiles of CLS in plasma and milk from lactating orally treated dairy goats to assess the residues pattern in dairy products such as cheese and ricotta. Six (6) female Saanen dairy goats were treated orally with CLS administered at 10mg/kg. Blood and milk samples were collected between 0 and 36days post-treatment. The whole milk production was collected at 1, 4, 7, and 10days post-treatment to produce soft cheese and ricotta. CLS concentrations in plasma, milk, cheese, whey, and ricotta were determined by HPLC. The concentrations of CLS measured in plasma were higher than those measured in milk at all sampling times. However, the calculated withdrawal time for CLS in milk was between 39 and 43days postadministration to dairy goats. CLS residual concentrations in cheese (between 0.93 and 1.8μg/g) were higher than those measured in the milk used for its production. CLS concentrations in ricotta were sixfold higher than those in the milk and 20-fold higher than those in the whey used for its production. The persistent and high residual concentrations of CLS in the milk and in the cheese and ricotta should be seriously considered before issuing any recommendation on the extralabel use of CLS in dairy goat farms.

Establishment and characterization of a dairy goat mammary epithelial cell line with human telomerase (hT-MECs).

Although research on dairy goat mammary gland have referred extensively to molecular mechanisms, research on lines of dairy goat mammary epithelial cells (MECs) are still rare. This paper sought to establish an immortal MEC line by stable transfection of human telomerase. MECs from a lactating (45 days post-parturition) Xinong Saanen dairy goat were cultured purely and subsequently transfected with a plasmid carrying the sequence of human telomerase. Immortalized MECs by human telomerase (hT-MECs) exhibited a typical cobblestone morphology and activity and expression levels of telomerase resembled that of MCF-7 cells. hT-MECs on passage 42 grew vigorously and 'S' sigmoid curves of growth were observed. Moreover, hT-MECs maintained a normal chromosome modal number of 2n=60, keratin 8 and epithelial membrane antigen (EMA) were evidently expressed, and beta-casein protein was synthesized and secreted. Beta-casein expression was enhanced by prolactin (P<0.05). Lipid droplets were found in hT-MECs, and messenger RNA levels of PPARG, SREBP, FASN, ACC and SCD in hT-MECs (passage 40) were similar to MECs (passage 7). In conclusion, the obtained hT-MEC line retained a normal morphology, growth characteristics, cytogenetics and secretory characteristics as primary MECs. Hence, it can be a representative model cell line, for molecular and functional analysis, of dairy goat MECs for an extended period of time.

ΔFosB regulates Ca²⁺ release and proliferation of goat mammary epithelial cells.

ΔFosB is a member of the family of transcription factor activating proteins-1 (AP-1) and is known to play important roles in Ca(2+) metabolism processes of osteoblast formation and differentiation in humans and rodents. The postpartum mammary gland is one of the significant organs for Ca(2+) metabolism processes. However, very little information is available on the role of ΔFosB in goat mammary gland. In this investigation, the full-length cDNA of ΔFosB from Xinong Saanen dairy goats was cloned, which contains an open-reading frame (ORF) of 723 bp encoding 240 amino acids. The amino acid sequence is highly homologous with cattle (99.17%). Quantitative real time PCR (QRT-PCR) and western blotting assays showed that ΔFosB was expressed in goat heart, liver, lung, and breast, but little in the hypophysis and spleen. The fluorescence signals revealed that the Ca(2+) was decreased in goat mammary epithelial cells (GMECs) over-expressed ΔFosB at 72h. Consistently, intracellular Ca(2+) was increased in GMECs suppressing expressed ΔFosB at 72 h. QRT-PCR assay showed that ΔFosB positively regulated the mRNA expression of runt related transcription factor 2 (Runx2), SMAD family member 4 (Smad4), S100 calcium binding protein A4 (S100A4) and S100 calcium binding protein A13 (S100A13) genes in GMECs, which had been proven to be relative to calcium metabolism in humans and rodents. Ca(2+) could induce a dose-dependent increase of the ΔFosB mRNA expression and a dose-dependent decrease in cell viability when the GMECs were treated with CaCl2. Suppressing ΔFosB expression in GMECs also inhibited the cell viability. These discoveries suggest that ΔFosB plays important roles in regulating Ca(2+) release and proliferation of the GMECs, which may prove useful in regulation of milk production.

Use of a staphylococcal vaccine to reduce prevalence of mastitis and lower somatic cell counts in a registered Saanen dairy goat herd

This investigation evaluated the efficacy of a bacterin in reducing the prevalence of staphylococcal mastitis and somatic cell counts (SCC) in a dairy goat herd. Does were vaccinated or left as controls, and the levels of mastitis and SCC monitored over 18 months. Staphylococcus caprae (42.5%), S. xylosus (15.1%), and S. simulans (10.0%) were the predominant causes of intramammary infections (IMI). The infection rate was 1.64 IMI/doe among vaccinates, which tended to be lower (P < 0.12) than controls (2.67 IMI/doe). The spontaneous cure rate of IMI after immunization was 1.28 cures/doe in vaccinates, which was higher than controls (0.6 cures/doe; P < 0.043). Average SCC of milk samples from vaccinates tended to be lower than that of controls (1274 × 103/ml vs. 1529 × 103/ml, respectively) (P < 0.10). Results support the continued study of mastitis vaccines for use in managing staphylococcal mastitis and SCC in dairy goats.

The Tankwa Karoo National Park feral goat population: A unique genetic resource

The feral goats from Tankwa Karoo National Park in the Northern Cape, South Africa, constitute a potentially unique goat population, which dates back to the early 1900s, but is now at risk of extinction. A total of 66 feral goats from Tankwa Park and former Tankwa goats, now kept on a private farm were genotyped, using eight microsatellite markers. The data were compared with genotypic data of selected commercial breeds (Angora, Boer and Saanen dairy goats). Analysis of population structure using Bayesian and frequency-based methods suggests some uniqueness in the Tankwa populations. This uniqueness may reflect decades of random drift, but could also reflect alleles for adaptation to a harsh environment resulting from natural selection. These results are the first for the Tankwa goat and provide essential information for compiling a strategy for conservation and breeding of this genetic resource.Keywords: Conservation, genetic variability, goat biodiversity, Tankwa feral goats

Effect of dietary physically effective fiber on ruminal fermentation and the fatty acid profile of milk in dairy goats

The objective of this experiment was to characterize the relationship among rumen fermentation variables, milk fatty acid profile, and dietary physically effective neutral detergent fiber (peNDF) content in a study that controlled for the potential confounding effects of dissimilar dry matter intake among treatments. Ten multiparous Xinong Saanen dairy goats were divided into 2 groups with 2 ruminally cannulated goats per group. Goats in each group were assigned to 1 of 2 dietary treatments (high and low peNDF) according to a 2×2 crossover design with 2 periods. The peNDF content of alfalfa hay (proportion of neutral detergent fiber retained on an 8.0-mm screen) was 42.1% for the high-peNDF and 14.5% for the low-peNDF group. To ensure similar dry matter intake, each morning the amount of alfalfa hay consumed on the prior day by the high-peNDF group was determined (amount offered minus morning refusals), and this was the amount of hay offered to the low-peNDF group that day. Each adaptation period consisted of 21d, followed by a 9-d sampling period. Dry matter intake and milk production and composition were similar between treatments. Milk energy efficiency increased with low dietary peNDF. Duration of pH below 5.60 was longer for goats fed the low-peNDF ration compared with the high-peNDF ration (4.08 vs. 0.41h/d); however, mean rumen pH (6.05 vs. 6.13) was not different between treatments. Reducing dietary peNDF increased rumen total volatile fatty acids (114.6 vs. 95.1mM) and decreased chewing time (404 vs. 673min/d), but did not affect the ratios of acetate, propionate, and butyrate. The relative abundance of Fibrobacter succinogenes and Ruminococcus flavefaciens increased with reduced dietary peNDF, but Ruminococcus albus proportions were not influenced by treatment. Reducing dietary peNDF decreased the proportion of iso C14:0, iso C15:0, and trans-11 C18:1 in milk fat, whereas the iso C17:0 and trans-10 C18:1 increased. This study demonstrated that low dietary peNDF in dairy goats increases rumen volatile fatty acids, reduces chewing time, and is correlated to the amount of F. succinogenes and R. flavefaciens.

Inhibition of FASN reduces the synthesis of medium-chain fatty acids in goat mammary gland

Fatty acid synthase (FASN) is known as a crucial enzyme of cellular de novo fatty acid synthesis in mammary gland which has been proved as the main source of short and medium-chain fatty acids of milk. However, the regulatory role of FASN in goat-specific milk fatty acids composition remains unclear. We cloned and analyzed the full-length of FASN gene from the mammary gland of Capra hircus (Xinong Saanen dairy goat) (DQ 915966). Comparative gene expression analysis suggested that FASN is predominantly expressed in fat, small intestine and mammary gland tissues, and expresses higher level at lactation period. Inhibition of FASN activity by different concentrations (0, 5, 15, 25 and 35 μM) of orlistat, a natural inhibitor of FASN, resulted in decreased expression of acetyl-CoA carboxylase α (ACCα), lipoprotein lipase and heart-type fatty acid binding protein (H-FABP) in a concentration-dependent manner in goat mammary gland epithelial cells (GMEC). Similar results were also obtained by silencing of FASN. Additionally, reduction of FASN expression also led to apparent decline of the relative content of decanoic acid (C10:0) and lauric acid (C12:0) in GMEC. Our study provides a direct evidence for inhibition of FASN reduces cellular medium-chain fatty acids synthesis in GMEC.

Genetic variants and effects on milk traits of the caprine paired-like homeodomain transcription factor 2 (PITX2) gene in dairy goats

The paired-like homeodomain transcription factor 2 (PITX2) gene plays a critical role in cell proliferation, differentiation, hematopoiesis and organogenesis. This gene regulates several genes' expressions in the Wnt/beta-catenin and POU1F1 pathways, thereby probably affecting milk performance. The goal of this study was to characterize the genetic variants of the PITX2 gene and test their associations with milk traits in dairy goats. Herein, four novel single nucleotide polymorphisms (SNPs), AC_000163:g.18117T>C, g.18161C>G, g.18322C>A and g.18353T>C, within the caprine PITX2 gene, were found in two famous Chinese dairy goat breeds. These SNPs mapping at Cys28Arg, Pro42Pro, IVS1+79C>A and IVS1+110T>C, were genotyped by the MvaI, SmaI, MspI and RsaI aCRS–RFLP or PCR–RFLP methods, respectively. Accordingly, two main haplotypes (CGCT and CGCC) were identified among the specimens. Association testing revealed that the SmaI and RsaI polymorphisms were significantly associated with the milk fat content, milk lactose content and milk density (P<0.05 or P<0.01) in the Guanzhong (GZ) dairy goats, respectively. At the same time, the RsaI locus was also found to significantly link to the second lactation milk yield, milk fat content, milk lactose content, milk density and milk total solid content (P<0.05 or P<0.01) in the Xinong Saanen (XNSN) dairy goats, respectively. These results indicated that the caprine PITX2 gene had the significant effects on milk traits. Hence, the RsaI and SmaI loci could be regarded as two DNA markers for selecting superior milk performance in dairy goats. These preliminary findings not only would extend the spectrum of genetic variation of the goat PITX2 gene, but also would contribute to implementing marker-assisted selection (MAS) in breeding and genetics in dairy goats.

Effects of pistachio by-products in replacement of alfalfa hay on ruminal fermentation, blood metabolites, and milk fatty acid composition in Saanen dairy goats fed a diet containing fish oil

The objective of this study was to investigate the effects of pistachio by-products (PBP) in replacement of alfalfa hay (AH) on ruminal fermentation, blood metabolites, and milk fatty acid composition in Saanen dairy goats fed a diet containing fish oil. For this purpose, 15 multiparous lactating Saanen goats (on day 25 postpartum, 38.15±1.2 kg) were randomly assigned to three treatment diets in a completely randomized design with five goats per treatment. The treatment consisted of feeding the following diets: (1) control (AH), (2) 30% PBP, and (3) 30% PBP + polyethylene glycol (PEG, 1 g/Kg of dry matter [DM]). The experiment lasted 21 days, including 16 days of adaptation to the experimental diets followed by a five-day sampling period for determining milk yield and composition, dry matter intake (DMI), and blood metabolites. The results showed that DMI was affected (P<0.05) by using PBP in the diets. The goats fed PBP had a lower (P<0.05) DMI than those in other treatments. No differences were observed in milk yield and composition among the dietary treatments. The goats fed PBP (with and without PEG) had higher (P<0.05) amounts of C16:0 and trans-C18:1 isomer in their milk fat than those fed AH. C24:0 was detected at higher (P<0.05) concentrations in goats fed AH than those in other treatments. Overall, different treatments had no significant effects on the concentrations of saturated, monounsaturated, and polyunsaturated fatty acids (PUFA) in milk fat. Trans fatty acids (TFA) in milk fat exhibited higher (P<0.05) concentrations in PBP and PBP-PEG treatments than in AH. However, no differences were detected in the concentrations of short, medium, and long chain fatty acids among the treatments. No differences were observed in rumen pH among the treatments, while rumen ammonia-N concentrations were lower (P<0.01) in goats fed PBP than those in the other treatments. Treatments showed no differences with regard to blood metabolites (i.e., cholesterol, triglyceride, blood urea nitrogen, total protein, albumin, and glucose). These findings indicate that the inclusion of PBP in replacement of AH in the diet of dairy Saanen goats have no adverse effects on ruminal fermentation and blood metabolites. Moreover, PBP is capable of modifying the fatty acid profile of milk in dairy goat.

Influence of altitude on vitamin D and bone metabolism of lactating sheep and goats1

This study investigated the influence of alpine grazing on vitamin D (vitD) and bone metabolism in sheep and goats. Two groups of five adult lactating East Friesian milk sheep and Saanen dairy goats were kept on pastures at 2,000 to 2,600 m a.s.l. (SA: sheep alpine; GA: goats alpine) and 400 m a.s.l. (SL: sheep lowland; GL: goats lowland). The animals were milked twice daily and the milk yield was measured. Blood, milk, skin, and forage samples were collected and the left metatarsi were measured with peripheral quantitative computed tomography. The relative humidity and air temperature were recorded and the ultraviolet B (UVB) radiation was measured with a solar meter at both research stations. In addition, animals from the alpine group were equipped with a global positioning system receiver. The UVB radiation was higher at the alpine station (P<0.05) compared to the lowland station. In contrast, both the relative humidity and the air temperature were higher at the lowland station (P<0.04). The group GA produced more milk than GL (P<0.043). No differences in milk production between SA and SL were detected. Only minor differences between the alpine and lowland species groups were found in the total 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D serum concentration and in the 25(OH)D milk concentration. 25-hydroxyvitamin D2 concentration in serum was higher in sheep compared to goats and the 25(OH)D3 concentration in serum increased in all four groups but was higher in the alpine groups during the experiment. In addition, no differences in 7-dehydrocholesterol (7-DHC) concentrations in the skin at high altitude and lowland groups were detectable. However the 7-DHC concentrations in the skin of sheep were less than a tenth of the concentrations in the skin of goats and were nearly not detectable. In both groups SA and SL bone strength index increased during the trial (P=0.043). Bone strength index was lower in GA compared to GL at wk 12 (P=0.047). Mean serum Ca concentrations were higher and P concentrations were lower in the alpine groups than in the lowland groups (P=0.047). In both groups SA and GA the distance travelled increased during the trial. In conclusion, no effect of altitude on vitD status, vitD milk concentration and bone strength could be detected. Both sheep and goats are able to produce vitD in the skin, but sheep depend more on vitD intake with feedstuff, whereas goats rely more on cutaneous vitD production.

Identification of Conservative MicroRNAs in Saanen Dairy Goat Testis Through Deep Sequencing

MicroRNA (miRNA) is a kind of small non-coding RNA molecules that function as important gene expression regulators by targeting messenger RNAs for post-transcriptional endonucleolytic cleavage or translational inhibition. In this study, small RNA libraries were constructed based on adult dairy goat testicular tissues and sequenced using the Illumina high-throughput sequencing technology. Blasted to miRNAs of cow and sheep in miRBase 19.0, 373 conserved miRNAs were identified in dairy goat testis and 91 novel paired-miRNAs were found. Expression of miRNAs in the dairy goat testis (miR-10b, miR-126-3p, miR-126-5p, miR-34c, miR-449b and miR-1468) was confirmed by qRT-PCR. In addition, the 128 conserved miRNAs were found by comparing the miRNA expression profiles in dairy goat testis with those in cow and mouse, which all might be involved in dairy goat testis development and meiosis. This study reveals the first miRNA profile related to the biology of testis in the dairy goat. The characterization of these miRNAs could contribute to a better understanding of the molecular mechanisms of reproductive physiology and development in the dairy goat.

Functional Analyse of GLUT1 and GLUT12 in Glucose Uptake in Goat Mammary Gland Epithelial Cells

Glucose transport, mediated by glucose transporters, is necessary for mammary gland development and lactation. GLUT1 and GLUT12 could both be expressed in the pregnant and lactating mammary gland to participate in the glucose uptake process. In this study, the goat GLUT1 and GLUT12 genes were cloned from Saanen dairy goats and transfected into goat mammary gland epithelial cells to assess their biological functions and distributions. The results showed that both goat GLUT1 and GLUT12 had 12 predicted membrane-spanning helices. Goat GLUT1 and GLUT12 each influenced the mRNA expression of the other transporter and increased the glucose consumption and lactose yield in GLUT1- and GLUT12-transfected goat mammary gland epithelial cells, respectively. The overexpression of GLUT1 or GLUT12 also increased the expression of amino acid transporters SLC1A5, SLC3A2 and SLC7A5 and affected genes expressions in GMGE cells. Using immunofluorescence staining, GLUT1 was detected throughout the cytoplasm and localized to the Golgi apparatus around the nuclear membrane, whereas GLUT12 was mainly distributed in the perinuclear region and cytoplasm. This study contributes to the understanding of how GLUT1 and GLUT12 cooperate in the incorporation of nutrient uptake into mammary gland epithelial cells and the promotion of milk synthesis in the goat mammary gland during lactation.

Environmental enrichment and social rank affects the fear and stress response to regular handling of dairy goats

Abstract Human–animal interactions can have result in fear and stress for the animals and can affect negatively their welfare and productivity. Environmental enrichment techniques can be a tool to reduce this fear response to handlers. The aim of this study was to analyze the effects of environmental enrichment and social rank on fear and stress response to handling of dairy goats. Thirty Saanen dairy goats (3.5-5 years of age) were observed 6 hours daily for 16 consecutive days. Behavior sampling was used to record all events of agonistic interactions, and index of success was calculated for each goat. Two groups, control (CO) and enriched (EN), of 12 goats each (6 high rank [HR] and 6 low rank [LR]), were then observed during a 4-phase handling test. Reactivity behaviors were recorded using focal sampling, and plasma cortisol was assessed in all goats. An analysis of variance (ANOVA) was used to assess the effect of treatment (EN and CO) and social rank (HR and LR) on behavior, and a multivariate ANOVA for repeated measures was used to assess the effect of treatment and social rank on cortisol levels in response to handling. The EN group and HR goats had a longer distance to the handler ( P P P P P P