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Large areas of tropical grass pastures are not grazed by lambs because of the difficulties in managing high growth rate swards with high selective animals. The objective of this study was to evaluate the physical and biochemical characteristics of tropical pastures offered to lambs in continuous grazing. An upright grass and a shrub legume were set out in three pasture types and grazed by lambs: (1) aruana grass monoculture (AG—Panicum maximum Jacq. cv. IZ‐5), (2) pigeon pea monoculture (PP—Cajanus cajan [L.] Millsp. cv. Anão) and (3) contiguous swards (CS), half of the paddock with AG (CSAG) and half with PP (CSPP). The pastures were evaluated for structural characteristics, production, nutritional composition and antioxidant concentrations in four periods over 92 days of continuous grazing by lambs. Hand plucking samples, similar to animal diet, were collected for chemical analysis. Regarding height, the PP legume monoculture after 42 days of grazing had uncontrollable growth by the lambs, reaching 1.2 m in height. This same legume but as a CS beside AG (CSPP) was maintained at a lower and similar height throughout the experimental periods. In general, the leaf:stem ratio of the different pastures decreased over the experimental periods from 0.7 to 0.2. In most periods, the CS showed intermediary nutritional quality compared to AG and PP. The alpha‐tocopherol content was similar among swards, with an average of 137.2 ± 13.67 mg/kg of green matter (p >.05). Pigeon pea showed the highest levels of total tannin and condensed tannin at 63 and 92 days (p <.05). The use of tropical grass together with a legume provides a better physical structure of the pigeon pea for grazing lambs than when monoculture of this species. [ABSTRACT FROM AUTHOR]

Abstract Background Alterations in lipid metabolism occur when animals are exposed to different feeding systems. In the last few decades, the characterisation of genes involved in fat metabolism and technological advances have enabled the study of the effect of diet on the milk fatty acid (FA) profile in the mammary gland and aided in the elucidation of the mechanisms of the response to diet. The aim of this study was to evaluate the effect of different forage diets (grazing vs. hay) near the time of ewe parturition on the relationship between the fatty acid profile and gene expression in the mammary gland of the Churra Tensina sheep breed. Results In this study, the forage type affected the C18:2 cis-9 trans-11 (CLA) and long-chain saturated fatty acid (LCFA) content, with higher percentages during grazing than during hay feeding. This may suggest that these FAs act as regulatory factors for the transcriptional control of the carnitine palmitoyltransferase 1B (CPT1B) gene, which was more highly expressed in the grazing group (GRE). The most highly expressed gene in the mammary gland at the fifth week of lactation is CAAT/ enhancer- binding protein beta (CEBPB), possibly due to its role in milk fat synthesis in the mammary gland. More stable housekeeping genes in the ovine mammary gland that would be appropriate for use in gene expression studies were ribosomal protein L19 (RPL19) and glyceraldehyde- 3- phosphate dehydrogenase (GAPDH). Conclusions Small changes in diet, such as the forage preservation (grazing vs. hay), can affect the milk fatty acid profile and the expression of the CPT1B gene, which is associated with the oxidation of fatty acids. When compared to hay fed indoors, grazing fresh low mountain pastures stimulates the milk content of CLA and LCFA via mammary uptake. In this sense, LCFA in milk may be acting as a regulatory factor for transcriptional control of the CPT1B gene, which was more highly expressed in the grazing group.

Abstract Background Conjugated linoleic acids (CLAs) are receiving increasing attention because of their beneficial effects on human health, with milk and meat products derived from ruminants as important sources of CLA in the human diet. SCD gene is responsible for some of the variation in CLA concentration in adipose tissues, and PPARγ, PPARα and SREBP1 genes are regulator of SCD gene. The aim of this work was to evaluate the effect of the feeding system on fatty acid composition, CLA content and relative gene expression of Δ9-desaturase (SCD), Peroxisome Proliferator-Activated Receptor Gamma (PPARγ), Peroxisome Proliferator-Activated Receptor Alpha, (PPARα) and Sterol Regulatory Element Binding Protein (SREBP1) in Rasa Aragonesa light lambs in semitendinous muscle. Forty-four single-born male lambs were used to evaluate the effect of the feeding system, varying on an intensity gradient according to the use of concentrates: 1. grazing alfalfa, 2. grazing alfalfa with a supplement for lambs, 3. indoor lambs with grazing ewes and 4. drylot. Results Both grazing systems resulted in a higher concentration of vaccenic acid (VA), CLA, CLA/VA acid ratio, and a lower oleic content, oleic acid (C18:1)/stearic acid (C18:0) ratio, PUFA n-6/n-3 ratio and SCD expression compared to other diets. In addition feeding system affected the fatty acid composition and SCD expression, possibly due to CLA concentration or the PUFA n-6/n-3 ratio. Both expression of the SCD gene and the feeding system were important factors affecting CLA concentration in the animal's semitendinous muscle. PPARγ, PPARα and SREBP1 expression seemed to be unaffected by the feeding system. Although no significant results were found, PPARγ, PPARα and SREBP1 showed similar expression pattern as SCD. Moreover, the correlation results between SCD expression and PPARγ (p < 0.01), as well as SREBP1 (p < 0.01) expression, may suggest that these genes were affecting SCD expression in a different way. Conclusions The data indicated that the feeding system is the main factor affecting the fatty acid composition and SCD gene expression, which is also affected by CLA and possibly by n-6/n-3 PUFAs.

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BACKGROUND: The objective of this study was to evaluate the effect of the proportion of pea (0%, 10%, 20%, and 30%), as a partial replacement for soybean meal (SBM) in the fattening concentrate, on ruminal fermentation in lambs. Gas and methane (CH4) production, in vitro dry matter degradability (IVDMD), ammonia (NH3‐N), and volatile fatty acid (VFA) production after 24 h of incubation were evaluated. The concentrates were also incubated in the rumen of the wethers for 2, 4, 6, 8, 12, and 24 h to evaluate the effects of pea inclusion on in situ dry matter degradability (DMD), organic matter degradability (OMD), nitrogen degradability (ND), NH3‐N, and VFA production. RESULTS: In the in vitro assay, the inclusion of pea only affected gas production (mL day−1 degraded dry matter), CH4 production (mL day−1 degraded dry matter), and IVDMD (P < 0.05), and tended to affect NH3‐N content (P < 0.10) without affecting VFA production. In the in situ assay, the inclusion of pea increased DMD, OMD, and ND linearly (P < 0.001), whereas pea inclusion decreased NH3‐N content linearly (P < 0.05). Neither total VFA production nor the proportion of acetic acid were affected by pea inclusion (P > 0.05), but the propionic proportion increased with the proportion of pea included. CONCLUSIONS: The best level of pea inclusion in the concentrate could not be established based on the results of this study. However, the results showed that the inclusion of pea provides a good alternative protein source. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Despite the fact that the use of rosemary and thyme residues and essential oils in animal feeding was widely documented, that of myrtle is scarce. To test the hypothesis that myrtle essential oils (MEOs) could improve goats' carcass characteristics and meat quality traits, twenty‐one male goats received a ration consisted of 40% oat hay and 60% concentrate. Experimental goat kids received the control diet supplemented with 0, 0.3 and 0.6% of myrtle essential oils (MEOs) for C, Myrt1 and Myrt2 groups respectively. The administration of MEO did not improve the daily DM intake (p > 0.05). Kids of C and Myrt2 groups had higher average daily gain than Myrt1 group (75 versus 55 g). The goats slaughtered at 19.9 kg of weight did not differ (p > 0.05) in carcass weights and carcass yield in terms of commercial dressing percentage (CDP = 41%) and real dressing percentage (RDP = 52%). The administration of MEO increased the meat polyphenol content, being higher in both Myrtle groups (87 versus. 56 μg gallic acid equivalents g‐1 fresh matter, p < 0.05). Myrtle EO administration protected kids' meat against oxidation (0.48 versus. 0.91 mg MDA/kg of meat for Myrtle and C groups, respectively, at the 9th day of storage; p < 0.05). It could be useful to include MEO as a dietary supplement in goats' rations since it improves meat's oxidative status without negative effects on FA profile. [ABSTRACT FROM AUTHOR]

BACKGROUND The interest for grazing systems and the use of condensed tannins (CTs) as sources of natural antioxidants in animal diets has been increasing in recent years. The objective was to study the animal performance and carcass quality of the lambs according to the feeding strategy during lactation (indoors, grazing alfalfa, grazing sainfoin) and the inclusion of quebracho as a source of CTs (50 g kg−1) in the fattening concentrate. RESULTS: The feeding strategy during lactation only had effects on carcass quality. Indoor lambs had a greater dressing percentage and deposition of kidney fat than sainfoin and alfalfa lambs. The kidney fat of sainfoin‐ and alfalfa‐fed lambs had a greater yellowness, chroma and carotenoid content than the fat of indoor‐fed lambs (P < 0.05), whereas the subcutaneous fat colour was not affected by the feeding during lactation. The use of fat colour to trace the feeding strategy was assessed and found insufficiently accurate to implement its use. The inclusion of 50 g kg−1 quebracho in the concentrate fed during the fattening period increased lamb weight gains and feed intake but had little effect on the carcass characteristics. CONCLUSIONS: The feeding strategies during lactation had an effect on the carcass characteristics, highlighting the importance of the dam's diet during this period. The inclusion of quebracho in the lamb's concentrate had minor effects. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The production of rosemary essential oils results in considerable amounts of rosemary residues (RR]. The purpose of this study was to assess the effects partial substitution of concentrate by feed blocks based on rosemary distillation residues (RR]. The effects on growth, digestibility, nitrogen retention and ruminal fermentation of Barbarme ewe-lambs were assessed. Sixteen fat tail ewe-lambs (26.1+1.2 kg] were divided into two comparable and homogeneous groups according to their body weight (BW]. The basal diet consisted of 600g of oat hay for all animals; the feed supply was 500g of concentrate for the control (C] group and 250g of concentrate plus rosemary feed blocks ad libitum for the rosemary blocks group (RB]. Hay intake was similar (P>0.05] for all lambs (517 and 529g of dry matter (DM]/day for C and RB, respectively], the concentrate intake was 427 and 214 g DM for C and RB, respectively, and the feed blocks intake was 84 g DM/day for RB group. Final BW and average daily gain (ADG] were lower in RB than in C (p<0.05]. Digestibility of DM, OM, NDF and ADF were lower in RB compared to C group, while crude protein (CP] digestibility and nitrogen retention were similar among treatments. Ruminal pH was slightly higher for RB group, however, ammonia (NH3-N] and total volatile fatty acids (TVFA] concentration were not influenced by treatment (P<0.05]. It was concluded that the partial substitution of concentrate by feed blocks based on rosemary residues resulted in lower DM intake and growth rate, similar nitrogen retention and comparable fermentation parameters comparing to a conventional diet based on hay and regular compound feed. [ABSTRACT FROM AUTHOR]

The production of rosemary essential oils results in considerable amounts of rosemary residues (RR]. The purpose of this study was to assess the effects partial substitution of concentrate by feed blocks based on rosemary distillation residues (RR]. The effects on growth, digestibility, nitrogen retention and ruminal fermentation of Barbarme ewe-lambs were assessed. Sixteen fat tail ewe-lambs (26.1+1.2 kg] were divided into two comparable and homogeneous groups according to their body weight (BW]. The basal diet consisted of 600g of oat hay for all animals; the feed supply was 500g of concentrate for the control (C] group and 250g of concentrate plus rosemary feed blocks ad libitum for the rosemary blocks group (RB]. Hay intake was similar (P>0.05] for all lambs (517 and 529g of dry matter (DM]/day for C and RB, respectively], the concentrate intake was 427 and 214 g DM for C and RB, respectively, and the feed blocks intake was 84 g DM/day for RB group. Final BW and average daily gain (ADG] were lower in RB than in C (p<0.05]. Digestibility of DM, OM, NDF and ADF were lower in RB compared to C group, while crude protein (CP] digestibility and nitrogen retention were similar among treatments. Ruminal pH was slightly higher for RB group, however, ammonia (NH3-N] and total volatile fatty acids (TVFA] concentration were not influenced by treatment (P<0.05]. It was concluded that the partial substitution of concentrate by feed blocks based on rosemary residues resulted in lower DM intake and growth rate, similar nitrogen retention and comparable fermentation parameters comparing to a conventional diet based on hay and regular compound feed. [ABSTRACT FROM AUTHOR]