Mid-lactating Goats Research Articles

Effects of acute and chronic heat stress on the rumen microbiome in dairy goats

Objective: The objective of this study was to reveal the influence of acute and chronic heat stress (HS) on the abundance and function of rumen microbiome and host metabolism.Methods: Forty mid-lactation goats were randomly divided into two artificial environments: control group and heat-stressed group. This study was recorded from two periods, 1 day and 28 days. The first day was defined as control 1 (CT1) and HS 1 (acute HS), and the last day was defined as CT28 and HS28 (chronic HS). On the first and last day, 6 dairy goats in each group were randomly selected to collect rumen liquid after the morning feeding through oral stomach tubes. The barn temperature and humidity were recorded every day.Results: Disruption of the rumen microbiome was observed under chronic HS, represented by an increase in the abundance of <i>Prevotella</i> and <i>Bacteroidales</i> (p<0.05), and upregulation of carbohydrate transport and metabolism functions (p<0.05). Additionally, the abundance of <i>Succinimonas</i> and <i>Ruminobacter</i> in chronic HS is lower than in acute HS (p<0.05), and the functions of intracellular trafficking, secretion and vesicular transport, and the cytoskeleton were downregulated (p<0.05).Conclusion: The HS affected the interaction between the microbiota and host, thereby regulated milk production in dairy goats. These findings increased understanding of the crosstalk between hosts and bacteria.

Effects of Parity and Somatic Cell Count Threshold on Udder Morphology, Milkability Traits, and Milk Quality in Canarian Goats.

The effects of parity and somatic cell count in milk (SCC) threshold on the udder morphology, milkability traits, and milk composition was evaluated in 41 Canarian goats in mid-lactation. The animals were divided according to parity (1st, 2nd, and 3rd), and a SCC threshold of 2000 × 103 cells/mL in milk was set to evaluate the effect of this factor on the different measured parameters. Results showed that primiparous goats had the udder smaller and less distended than multiparous goats, but no differences were detected on milk flow parameters. Furthermore, SCC and total bacterial count (TBC) tended to be higher when the parity increased. On the other hand, goats with SCC ≤ 2000 × 103 had higher cistern-floor distance (CF) and lower TBC values compared with those goats with a count above the predetermined threshold. The results suggest that a reduction in SCC can be achieved by a selection of udder morphological traits. Moreover, milk flow parameters do not seem to be a tool to determine the udder health status in Canarian goats, but long-term studies are needed to verify it.

Total Replacement of Soybean Meal with Sundried Soymilk Residue in the Total Mixed Ration has a Negative Impact on Intake, Digestibility, and Milk Production in Dairy Goats.

This study aimed to evaluate whether total replacement of soybean meal (SBM) with sundried soymilk residue (SSR) in a total mixed ration (TMR) affects intake, digestibility, milk production, and blood metabolites in dairy goats. A total of 12 healthy Saanen dairy goats (40.12 ± 5.80 kg of BW) in midlactation (31.23 ± 10.12 days) were used in a randomized complete design (n = 4 goats/group). Dietary treatments were based on a TMR as follows: control TMR without SSR (CON) or SBM-based TMR with 50% or 100% of SSR replacing SBM (SSR-50 and SSR-100, respectively). All goats had ad libitum access to feed and clean water throughout the experiment. The dry matter (DM) intake decreased (p < 0.05) with the increasing replacement ratio of SBM and was lowest in the SSR-100 group. Similarly, organic matter (OM) digestibility was lowest (p < 0.05) in the SSR-100 group. However, the digestibility of DM, CP, NDF, and ADF did not change (p > 0.05) by dietary treatments. Compared with CON, the milk yield decreased significantly (p < 0.05) with increasing replacement ratio of SBM. In contrast, milk composition such as total solids, solids-not-fat, milk fat, lactose, protein, and pH were not influenced (p > 0.05) by feeding dietary SSR. Compared with other treatments, blood glucose concentration was lower (p < 0.05) in the SSR-100 group. In contrast, packed cell volume, glucose, and plasma urea nitrogen concentrations did not differ (p > 0.05). The results indicated that SSR could replace SBM in a TMR at less than 50%. Thus, the present study provides support for further investigation to enhance the utilization of soybean waste as an alternative protein source in the TMR for dairy goats and potentially other ruminants.

The Dietary Inclusion of Ensiled Olive Cake Increases Unsaturated Lipids in Milk and Alters the Expression of Lipogenic Genes in Mammary and Adipose Tissue in Goats.

This study aimed to evaluate the effect of the dietary inclusion of ensiled OC on milk yield, composition, fatty acid (FA) profile, and the expression of selected genes involved in lipid metabolism in the udder and adipose tissue of goats. Seventy-two Damascus dairy goats in mid-lactation were assigned randomly to three iso-nitrogenous and iso-energetic diets containing 0, 10, and 20% of ensiled OC as a replacement of forage (OC0, OC10, and OC20, respectively) for 42 days. During weeks 5 and 6 of the trial, dry matter intake, milk yield, milk composition, and FA profiles were recorded, while mammary and perirenal adipose tissue samples were also collected from six animals per treatment from the OC0 and OC20 groups for gene expression analysis. No significant differences were observed among groups concerning milk yield, 4% fat-corrected milk, fat, or protein yield (kg/d). In contrast, the milk fat percentage was gradually increased with increasing OC inclusion rates in the diets, while milk protein percentages were elevated in both OC groups but significantly only in the milk of the OC20 group. The content of FA between C4:0 to C16:0 was reduced, while mono-unsaturated FA (MUFA) concentration was enhanced in the goat milk of OC groups. The OC feeding treatment was associated with the increased mammary expression of SLC2A1 (p < 0.05), VLDLR (p < 0.01), FABP3 (p < 0.01), and elevated SLC2A1 (p < 0.05) and FASN (p < 0.01) gene expression in the adipose tissue of goats fed the OC20 diet. Overall, OC can be used in goats' diets as a forage replacement, at least in the inclusion rate of 20% DM, since this could increase the milk protein and fat percentage and enrich its content with beneficial for human health lipids without adversely affecting milk production traits.

Effect of Fish Oil and Linseed Oil on Intake, Milk Yield and Milk Fatty Acid Profile in Goats.

This study aimed to evaluate the effect of incorporating linseed oil and fish oil in the diet on intake, ruminal fermentation, milk yield, and milk fatty acid profiles in dairy goats. Four crossbred Saanen lactating goats in mid-lactation and milking 1.30 ± 0.28 g/day were used in a 4 × 4 Latin square design. The basal diet contained concentrate and Para grass (C:F 40:60). Treatments included a basal diet without oil supplementation (Ctrl) or with 2.5% linseed oil (LO2.5), 2.5% linseed oil and fish oil (3:2, w/w, LFO2.5), and 4.16% linseed oil and fish oil (3:2, w/w, LFO4.16). Diets had no effect on intake, milk yield, milk composition, or ruminal fermentation (p > 0.05). Compared with Ctrl, lower (p < 0.05) proportions of C10:0-C14:0 in milk fat were observed with LFO4.16. Compared with the Ctrl and linseed oil added alone, feeding LFO4.16 led to a greater (p < 0.01) concentration of C18:1 t11. Compared with both the Ctrl and LO2.5 diets, milk c9,t11 CLA was 4.53 and 2.94 times greater with the LFO4.16 diet. Compared with Ctrl and LO2.5 diets (0.06% and 0.08%), goats fed LFO2.5, and LFO4.16 had greater (p < 0.001) concentrations of C22:6n-3 (0.63% and 0.87%). Overall, the combined data suggested that including 4.16% linseed oil and fish oil in the diet of dairy goats was effective in improving the concentrations of health-promoting fatty acids in milk without affecting milk production.

Natural high ambient temperature-induced respiratory hypocapnia without activation of the hypothalamic-pituitary-adrenal axis in lactating goats.

Activation of breathing, the hypothalamic-pituitary-adrenal (HPA) axis, and plasma antioxidant defense are adaptive mechanisms in lactating dairy goats fed during the summer season. However, an excess of these responses can interfere with the gas exchange. This study aimed to investigate the effect of natural high ambient temperature (HTa) on blood gas parameters and their relation to the HPA axis and antioxidant defense. Six mid-lactating goats were included in this study and were fed in individual pens for 2 weeks. The data on ambient conditions, physiological responses, and blood chemistry were measured for two sampling days (D7 and D14), 1 week apart during the late summer season. On this two-sampling day, the main physiological responses to HTa, including respiration rate (RR), rectal temperature (Tr), blood gas, and blood chemistry, were measured in the morning and afternoon. Goats from both D7 and D14 increased RR and Tr significantly according to morning and afternoon periods. In addition, goats were at the hypocapnia stage during afternoon panting without a change in blood pH and bicarbonate levels. Interestingly, HTa-induced hypocapnia was not accompanied by an increase in plasma cortisol levels. Finally, ΔTa was negatively correlated with changes in glutathione peroxidase activity. The natural HTa (ΔTa; 5-8°C) in this study activated evaporative heat dissipation and was high enough to induce respiratory hypocapnia. Importantly, this ΔTa did not activate the HPA axis but was correlated with a change in antioxidant defense. Therefore, under natural HTa in tropical conditions, respiratory hypocapnia is the first line of physiological response in goats within a specific range of natural ΔTa (5-8°C).

Jackfruit leaves can totally replace traditional grass in the diet of lactating dairy goats

ABSTRACT This study aimed to evaluate the effect of replacing jackfruit leaves (JF) for Para grass (PG) on intake, digestibility, nitrogen balance, ruminal fermentation, milk yield and composition in lactating goats. Four crossbred Saanen lactating goats in mid-lactation and milking 1676 ± 112 g/day were used in a 4 × 4 Latin square design. A basal diet consisted of concentrate and PG (C:F 40:60). Treatments were dietary replacement of JL for PG at ratios of 0, 50, 75 and 100% corresponding to JL0, JL50, JL75 and JL100 diets, respectively. Feeding JL increased linearly (P < 0.01) DM intake, but decreased linearly (P < 0.05) nutrient digestibility. A linear increase in fecal N (P < 0.01) and N retention (P = 0.04), but a linear decrease in urinary N (P = 0.03) was detected when increased the JL in the diets. Total VFA concentration increased quadratically (P = 0.04), and the highest value was observed in JL75 compared with JL0 (85.9 vs. 72.8 mM). Milk production increased linearly (P = 0.03), but no change was observed in milk composition and blood urea nitrogen (BUN). Overall, combined data suggest that the substitution of JL for PG in lactating goat diets is effective in the improvement of nutrient intake, N retention, ruminal VFA concentration and milk yield without affecting milk composition and BUN.

Effect of the Short-Term Incorporation of Different Proportions of Ensiled Artichoke By-Product on Milk Parameters and Health Status of Dairy Goats

The use of local agricultural by-products for animal feed is an alternative that reduces livestock production costs and allows food production of greater environmental sustainability. The aim of this experiment was to study the effect of the inclusion in the dairy goat ration of artichoke by-product silage (ABS) at three levels (25%, 40% and 60%, on a dry matter basis) on the milk yield, composition and quality, and on the metabolic profile of dairy goats. Thirty-six Murciano-Granadina dairy goats in mid-lactation were divided into four groups with homogeneous characteristics. Each group was assigned a diet: a control treatment (C) that consisted of a conventional diet of alfalfa hay and concentrate, and three other treatments that included 25, 40 and 60% ABS: ABS25, ABS40 and ABS60. Small differences were observed in the milk yield and quality and the health status of the animals. Only ABS60 presented a slightly lower milk yield (−20% compared to control group), without relevant differences in the milk composition and mineral profile. Regarding the lipid profile, ABS40 was the treatment with the best milk quality, due to a higher content of polyunsaturated fatty acids (4.37%) and lower atherogenicity (1.90) and thrombogenicity indices (3.05), without differences from C. It was concluded that the maximum inclusion level of ABS in dairy goats’ diet should be equal to 40%.

Effects of a High-Grain Diet With a Buffering Agent on Milk Protein Synthesis in Lactating Goats.

Chinese dairy industries have developed rapidly, providing consumers with high-quality sources of nutrition. However, many problems have also appeared during the development process, especially the low quality of milk. To improve milk quality, a large amount of concentrated feed is usually added to the diet within a certain period of time, which increases the milk production to a certain extent. However, long-term feeding with high-concentration feed can lead to subacute rumen acidosis. Therefore, the present study aimed to determine the effect of adding a buffer on subacute rumen acidosis, and the improvement of milk production and milk quality. We also aimed to study the mechanism of promoting mammary gland lactation. A total of 12 healthy mid-lactating goats were randomly divided into two groups, they were high-grain diet group (Control) and buffering agent group. To understand the effects of high-grain diets with buffers on amino acids in jugular blood and the effects of amino acids on milk protein synthesis, Milk-Testing™ Milkoscan 4000, commercial kits, and high-performance liquid chromatography (HPLC) measurements were integrated with the milk protein rate, the amino acid concentration in jugular venous blood samples, quantitative real-time PCR, comparative proteomics, and western blotting to study differentially expressed proteins and amino acids in mammary gland tissues of goats fed high-grain diets. Feeding lactating goats with buffering agent increased the percentage of milk protein in milk, significantly increased the amino acid content of jugular blood (p < 0.05), and increase the amino acid transporter levels in the mammary gland. Compared with the high-grain group, 2-dimensional electrophoresis technology, matrix-assisted laser desorption/ionization-time of flight/time of flight proteomics analyzer, and western blot analysis further verified that the expression levels of beta casein (CSN2) and lactoferrin (LF) proteins in the mammary glands of lactating goats were higher when fed a high-grain diets and buffers. The mechanism of increased milk protein synthesis was demonstrated to be related to the activation of mammalian target of rapamycin (mTOR) pathway signals.

Dietary Starch Concentration Affects Dairy Sheep and Goat Performances Differently during Mid-Lactation.

Simple SummaryIn order to favor milk production, this research suggests that the concentration of starch in the diet of dairy ewes in mid-lactation should be reduced, compared to early lactation, by introducing sources of highly digestible fiber. On the other hand, this type of diet is not adequate for dairy goats, which should maintain the use diets rich in starch, even in mid-lactation, to support milk yield, as well.Evolution of milk production, body reserves and blood metabolites and their relationships with dietary carbohydrates were compared in 30 Sarda dairy ewes and 26 Saanen dairy goats in mid-lactation. From 92 to 152 ± 11 days in milk (DIM), each species was allocated to two dietary treatments: high-starch (HS: 20.0% starch, on DM basis) and low-starch (LS: 7.8% starch, on DM basis) diets. In mid-lactating goats, the HS diet increased fat-corrected milk yield (FCM (3.5%); 2.65 vs. 2.53 kg/d; p = 0.019) and daily milk net energy (NEL; p = 0.025), compared to the LS diet. The body condition score (BCS) was not affected. In mid-lactating ewes, the LS diet increased FCM (6.5%) (1.47 vs. 1.36 kg/d; p = 0.008), and NEL (p = 0.008), compared to the HS diet. In addition, BCS was greater in HS than in LS ewes (3.53 vs. 3.38; p = 0.008). Goats had a higher growth hormone (GH) and lower insulin concentration than ewes (GH: 2.62 vs. 1.37 ng/mL; p = 0.04; insulin: 0.14 vs. 0.38 µg/L; p < 0.001 in goats and ewes, respectively). In conclusion, in mid-lactation, the two species responded differently to dietary carbohydrates, probably due to differences in the concentration of GH and insulin. The HS diet favored milk yield in goats and body reserve accumulation in ewes. In ewes, the partial replacement of starch with highly digestible fiber increased energy partitioning in favor of milk production.

Sesame Meal, Vitamin E and Selenium Influence Goats' Antioxidant Status.

This study aimed to determine the impact of sesame meal, selenium (Se), and vitamin E (VitE) on goats’ oxidative status. Thirty mid-lactation crossbred goats were divided into five homogeneous groups, and were fed 1 kg of alfalfa hay and 1.2 kg of concentrates daily. The control group (C) received a basal diet. In the concentrates of the treated groups, 10% of the soybean meal was replaced by sesame meal and no extra VitE or Se (SM), or an extra 60 mg of VitE (SME), or 0.1 mg organic Se (SMSe), or their combination (60 mg VitE and 0,1 mg organic Se/kg of concentrate (SMESe). In the plasma of the goats, the dietary treatments did not affect glutathione reductase, glutathione peroxidase, glutathione transferase, catalase, superoxide dismutase activities, malondialdehyde (MDA) content, or the total antioxidant capacity. A reduction and a trend for lower protein carbonyls content was found in goats fed SM (p = 0.03) and SME (p = 0.06) compared to SMESe. In the milk, the lactoperoxidase activity decreased with SMSe and SMESe. A numerical decrease in the total antioxidant capacity and an increase in the MDA content in the milk of the SMESe group compared with the other treated groups was found. In mid-lactation goats, SM improves the oxidative status of both the organism and the milk.

Inclusion of lemon leaves and rice straw into compound feed and its effect on nutrient balance, milk yield, and methane emissions in dairy goats

The objective of this experiment was to study the effects of incorporating lemon leaves and rice straw into the compound feed of diets for dairy goats. Ten Murciano-Granadina dairy goats (n = 5 per group) in mid-lactation were used in a crossover design experiment (2 treatments across 2 periods). Goats were fed a mixed ration with barley grain (control, CON) or CON plus lemon leaves [189 g/kg of dry matter (DM)] and rice straw (120 g/kg of DM) in place of barley grain (LRS). Soybean oil (19 g/kg of DM) was added to the LRS diet to make it isoenergetic (17 MJ of gross energy/kg of DM) relative to CON. After 14 d on their respective treatments, goats were allocated to individual metabolism cages for another 7 d. Subsequently, feed intake, total fecal and urine output, and milk yield were recorded daily over the first 5 d. During the last 2 d, ruminal fluid and blood samples were collected, along with individual gas exchange measurements recorded by a mobile open-circuit indirect calorimetry system using a head box. No differences in DM intake were detected, and ME intake in LRS was lower than in CON (1,095 vs. 1,180 kJ/kg of metabolic body weight). No differences were observed in milk production, but milk fat content was greater in LRS (6.4%) than in CON (5.6%). Greater concentrations of monounsaturated (14.94 vs. 11.96 g/100 g of milk fat) and polyunsaturated fatty acids (4.53 vs. 4.03 g/100 g of milk fat) were detected in the milk of goats fed LRS compared with CON. Atherogenicity (2.68 vs.1.91) and thrombogenic (4.58 vs. 2.81) indices were lower with LRS compared with CON. Enteric CH4 emission was lower in LRS (24.3 g/d) compared with CON (31.1 g/d), probably due to the greater lipid content and unsaturated fatty acid profile of lemon leaves and the soybean oil added in the LRS diet. Overall, data suggest that incorporating lemon leaves and rice straw into lactating goat diets is effective in reducing CH4 emissions while allowing improvements in milk fat production and milk thrombogenic index without affecting production performance. Thus, their inclusion in compound feeds fed to small ruminants appears warranted and would have multiple positive effects, as on efficiency of nutrient use, human health, and the environment.

Intake, milk production and grazing behaviour responses of strip-grazing dairy goats to daily access time to pasture and to dehydrated lucerne supplementation

The ability of grazing dairy goats to adapt to short daily access time to pasture is not well known, while, in practice, access time to pasture (AT) is often lower than 12 h/d. A 3-week trial was carried out in spring with 36 Alpine dairy goats in mid-lactation to study the effect of a restriction of access time to pasture, coupled or not with a dehydrated lucerne supplement. Three treatments were compared: (1) 7 h/d of access time to pasture, between milkings, without dehydrated lucerne (namely AT7); (2) 7 h/d of access time to pasture, between milkings, with 371 g DM/d of dehydrated lucerne, distributed individually after evening milking (namely AT7D); and (3) 11 h/d of access time to pasture, 7 h/d between milkings plus 4 h/d after evening milking, without dehydrated lucerne (namely AT11). The daily pasture allowance was 2.3 kg DM/goat at 4 cm above ground level in each treatment. Each goat received 602 g DM/d of a commercial concentrate, given twice daily at milking. Pasture intake decreased by 433 g DM/d (i.e. 18%) between AT11 and AT7 (P<0.01). Pasture intake also decreased by 259 g DM/d between AT7 and AT7D (P<0.01), which means a substitution rate of 0.72 between pasture and dehydrated lucerne. Milk production, and milk fat and protein concentrations were not affected by AT (P>0.10). Milk production response to dehydrated lucerne was 0.82 kg of milk/kg DM. Grazing time decreased by 2.5 h/d between AT11 and AT7 or AT7D (P<0.001). The pasture intake rate averaged 272 g DM/h and tended to increase between AT11 and AT7 (P = 0.08). It is concluded that an access time to pasture of 7 h/d may be sufficient for lactating dairy goats receiving 600 g/d of concentrate and grazing high-quality pastures. Supplying 400 g/d of dehydrated lucerne has a much stronger positive effect on milk production than an additional grazing period of 4 h after evening milking.

Intake, milk yield and grazing behaviour of strip-grazing Alpine dairy goats in response to daily pasture allowance

Grazing management has an important impact on dairy ruminants’ performance. References on the intake and milk yield of dairy goats under strip-grazing systems in temperate regions are scarce. In order to study the effect of pasture allowance on pasture intake (PI), milk yield and grazing behaviour, a trial was carried out in spring with 36 Alpine goats in mid-lactation. Three daily pasture allowances (PA=1.7, 2.6 and 3.5 kg dry matter (DM)/day, namely Low, Medium and High, respectively) were compared in a 3 × 3 Latin square design replicated six times during three successive 14-day periods. Goats individually received 268 g DM of concentrate twice daily at each milking and had access 11 h/day to pasture (from 0830 to 1600 h and from 1730 to 2100 h). Pasture intake increased with PA, and more so between Low and Medium than between Medium and High (+216 v. +101 g DM/kg DM of PA). Milk yield was lower on Low than on Medium and High (2.79 v. 3.13 kg/day), as were milk fat and protein yields. Grazing time averaged 476 min/day and was lowest on Low and greatest on Medium. Pasture intake rate was 30 g DM/h lower on Low and Medium than on High. It is concluded that under temperate conditions, when goats are supplemented with 536 g DM of concentrate and have enough access time to pasture (11 h/day), a medium pasture allowance close to 2.6 kg DM/day may be sufficient to maximise milk yield.

The effect of cultivated mixed-species green fodder on intake, milk production and milk composition of housed dairy goats

The majority of New Zealand dairy goat farmers utilise cultivated green-fed fodder dominated by perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), but evidence from other ruminant species suggests that milk production may be improved when using a more diverse array of species within the green fodder. The aim of this experiment was to determine whether feeding lactating dairy goats a mixed-species green fodder (MF, consisting of perennial ryegrass, timothy (Phleum pratense L.), prairie grass (Bromus willdenowii Kunth), white clover, red clover (Trifolium pratense L.), lucerne (Medicago sativa L.), chicory (Cichorium intybus L.) and plantain (Plantago lanceolata L.) improves dietary intake, milk yield and composition compared with a standard ryegrass and white clover green fodder (SF). Thirty-six mid-lactation goats were housed indoors in pairs and split into two groups (A and B). The trial was split into three periods – firstly a uniformity period of 6 days, in which all goats were fed a combination of both green fodder types, followed by two treatment periods (P1 and P2) of 12 days, respectively. For P1, group A was fed MF and group B was fed SF, and then the group diets were switched for P2. Goats fed MF had 13% greater dry matter intake and 7% greater milk yield than goats fed SF. In addition, the milk protein and fat concentration of goats fed MF were 4% greater than for those fed SF, whereas there was no effect on milk lactose concentration. There was no treatment effect on the levels of protein, glucose, urea or non-esterified fatty acids in the blood of the goats. An effect of green fodder type on milk fat profile was demonstrated, with proportions of pentadecylic acid (C15:0), cis-vaccenic acid (C18:1 c11), linoleic acid (C18:2 n6) and α-linolenic acid (C18:3 n3) being increased in response to MF consumption. In contrast, iso-C15 and iso-C17 proportions were lesser. In summary, this study demonstrated that goats fed MF increased green fodder intake and milk production compared with goats fed SF. The green fodder type affected the fatty acid profile of goat’s milk, with MF increasing the levels of beneficial polyunsaturated omega fatty acids (linoleic and α-linolenic acids).

Use of orange leaves as a replacement for alfalfa in energy and nitrogen partitioning, methane emissions and milk performance of murciano-granadina goats

The objective of this experiment was to study the effects of substituting alfalfa with orange leaves on energy, nitrogen and carbon balance, methane emission, and milk performance in dairy goats. Ten Murciano-Granadina dairy goats in mid lactation (43.5 ± 3.59 kg of body weight [BW]) were selected in a crossover design experiment, where each goat received two treatments in 2 periods. One group of five goats was fed a mixed ration with 450 g of pelleted alfalfa and 550 g of pelleted concentrate/kg of dry matter (ALF diet), and the other diet replaced alfalfa with orange leaves (ORG diet). Inclusion of ORG than ALF diet reduced (P = 0.041) dry matter intake. The metabolizable energy intake was identical between treatments (901 kJ/kg of BW0.75, on average) and, the efficiency of metabolizable energy for milk production was 0.73. Retention of energy was lower (P = 0.001) in ORG diet than ALF diet. Carbon and nitrogen intake (P = 0.022 and P = 0.004, respectively) was greater for diet ALF than ORG, with no differences in milk carbon and nitrogen. The ORG diet reduced (P = 0.037) milk fat 3 g/kg, and CH4 (P = 0.001) 6 g/d. One of the milk fatty acids positively correlated with CH4 production was C16:0; it was greater (P < 0.05) in ALF than ORG diet. When CH4 was expressed over OM digestibility and milk basis, differences were preserved. Results suggest that orange leaves are effective in reducing CH4 emission without detrimental effect on nutrients balance and milk yield.

Effects of chronic heat stress on lactational performance and the transcriptomic profile of blood cells in lactating dairy goats.

High temperature is a major stress that negatively affects welfare, health, and productivity of dairy animals. Heat-stressed animals are more prone to disease, suggesting that their immunity is hindered. Although productive and physiologic responses of dairy animals to heat stress are well known, there is still limited information on the response at the transcriptome level. Our objective was to evaluate the changes in performance and blood transcriptomics of dairy goats under heat stress. Eight multiparous Murciano-Granadina dairy goats in mid-lactation were assigned to 1 of 2 climatic treatments for 35 d. Treatments and temperature-humidity index (THI) were: (1) thermal neutral (TN: n = 4; 15-20 °C, 40-45%, THI = 59-65), and (2) heat stress (HS: n = 4; 12 h at 37 °C-40%, THI = 86; 12 h at 30 °C-40%, THI = 77). Rectal temperature, respiratory rate, feed intake and milk yield were recorded daily. Additionally, milk composition was evaluated weekly. Blood samples were collected at d 35 and RNA was extracted for microarray analyses (Affymetrix GeneChip Bovine Genome Array). Differences in rectal temperature and respiratory rate between HS and TN goats were maximal during the first 3 d of the experiment, reduced thereafter, but remained significant throughout the 35-d experimental period. Heat stress reduced feed intake, milk yield, milk protein and milk fat contents by 29, 8, 12, and 13%, respectively. Microarray analysis of blood revealed that 55 genes were up-regulated, whereas 88 were down-regulated by HS. Bioinformatics analysis using the Dynamic Impact Approach revealed that 31 biological pathways were impacted by HS. Pathways associated with leukocyte transendothelial migration, cell adhesion, hematopoietic cell lineage, calcium signaling, and PPAR signaling were negatively impacted by HS, whereas nucleotide metabolism was activated. In conclusion, heat stress not only negatively affected milk production in dairy goats, but also resulted in alterations in the functionality of immune cells, which would make the immune system of heat-stressed goats less capable of fending-off diseases.

NOD1/NF-κB signaling pathway inhibited by sodium butyrate in the mammary gland of lactating goats during sub-acute ruminal acidosis

Animals nurtured with a high-concentrate diet for a more extended period can cause subacute ruminal acidosis (SARA). In this study, twelve mid-lactating goats were separated into two groups (n = 6): a high concentrate diet (HC) control and a high concentrate with buffer (HCB) treatment group. Rumen fistula was installed in all lactating goats in the 14th week of the experiment. Goats were slaughtered in the 24th week. Our results showed that a pH value < 5.8 sustained at different periods of time for more than 3 h/day in the group HC, which confirms that SARA was prompted efficiently. Additionally, the group HCB exhibited lower concentration of LPS in peripheral blood than the group HC. Radioimmunoassay revealed a substantial reduction in the concentration level of proinflammatory cytokines in the lacteal blood of the group HCB compared to group HC. The transcriptional profiles in mammary gland following different treatments showed a significant decrease in the expression of NOD1, IKβ, and NF-κB in HCB group, followed by a decreased transcriptional level of (TNF-α, IL-1β and IL-6). Our research explores that HC diet nurtured to lactating goats for a more extended period can induce SARA by increasing the LPS and proinflammatory cytokine concentrations in plasma, that ultimately triggers the NOD1/NF-κB inflammatory pathway and induce mammary cell inflammation. Additionally, oral supplementation of sodium butyrate can decrease the concentrations of LPS and proinflammatory cytokines and inhibits NOD1/NF-κB inflammatory pathway.

Milk production and grazing behaviour responses of Alpine dairy goats to daily access time to pasture or to daily pasture allowance on temperate pastures in spring

In a context of price volatility and low feed self-sufficiency of goat farms in Western Europe, grazing may play an important role. Knowledge about the impact of grazing management – particularly daily access time to pasture or pasture allowance – on dairy goats’ performance is scarce. Two 3-week trials were carried out in spring with 36 Alpine goats in mid-lactation. In Trial 1, 3 access times to pasture during daytime (AT: 4, 6 or 8 h/day, from 08:00 to 12:00, from 10:00 to 16:00 and from 08:00 to 16:00, respectively) were compared. In each treatment, goats individually received 370 g DM of dehydrated forage (lucerne and maize) after the evening milking, 278 g DM of concentrate twice daily, at each milking, and a daily pasture allowance of 2.0 kg DM/goat, measured at 4 cm above ground level. In Trial 2, 3 daily pasture allowances (PA: 1.6, 2.3 or 3.0 kg DM/goat, measured at 4 cm above ground level) were compared. Goats individually received 278 g DM of concentrate twice daily, at each milking, and access time to pasture was of 13 h/d (from 07:30 to 16:00 and from 17:00 to 21:30). Milk production was similar between medium and high levels of AT or PA, and was lower for the lowest level of AT or PA (−300 g/d at the lowest AT and −500 g/d at the lowest PA). Milk fat and protein concentrations only slightly varied between the different levels of AT or PA. In both trials, goats maintained an intense grazing activity. Grazing time (from 240 to 540 min/d) and proportion of time spent grazing (from 66 to 99%) were mainly affected by AT, and only marginally by PA.

Pathogenesis and inflammatory response in experimental caprine mastitis due to Staphylococcus chromogenes

Coagulase-negative staphylococci (CNS) are the most frequently isolated bacteria in cases of subclinical mastitis in dairy cows. CNS species may differ in their pathogenicity, but very little is known about their virulence factors or their immune response in intramammary infections. To our knowledge, no experimental studies into the mastitis pathogenesis caused by CNS have been described in lactating goats. The aim of this study was to induce an experimentally Staphylococcus chromogenes mastitis in lactating goats aimed at verifying if the model can be used to evaluate the inflammatory response, the dynamics of infection and the pathological findings within the first hours of intramammary inoculation. Six Saanen goats in mid-lactation were inoculated with 1 × 107 colony forming units of S. chromogenes. Bacterial growth peaked in milk from the challenged right halves of the mammary glands (RMG) at 4 h post inoculation (PI). Shedding of viable bacteria showed a marked decrease at 12 h PI. An increase in mean somatic cell counts was observed in the milk samples from 8 h PI onwards. Mild clinical signs were evoked by intramammary inoculation. Staphylococcus chromogenes could be isolated in tissue from all RMG. Histological examination of specimens of the RMG and lymph nodes of the goats showed an increased inflammatory response throughout the experiment with respect to control halves. In conclusion, the experimental inoculation of S. chromogenes in lactating goats is capable of eliciting an inflammatory response and capable of causing pathological changes. This research represents a preliminary study for a better knowledge of the mastitis pathogenesis caused by S. chromogenes.