Evaluation of the growth performance and meat quality of Mongolian lamb fed grass, hay or pellets of Inner Mongolian native grass

Evaluation of the growth performance and meat quality of Mongolian lamb fed grass, hay or pellets of Inner Mongolian native grass

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Journal Pre-proof Evaluation of the growth performance and meat quality of Mongolian lamb fed grass, hay or pellets of Inner Mongolian native grass S. Du, S.H. You, J. Bao, Gegentu, Y.S. Jia, Y.M. Cai

PII:

S0921-4488(19)30208-1

DOI:

https://doi.org/10.1016/j.smallrumres.2019.10.008

Reference:

RUMIN 6007

To appear in:

Small Ruminant Research

Received Date:

9 April 2019

Revised Date:

22 October 2019

Accepted Date:

23 October 2019

Please cite this article as: Du S, You SH, Bao J, Gegentu, Jia YS, Cai YM, Evaluation of the growth performance and meat quality of Mongolian lamb fed grass, hay or pellets of Inner Mongolian native grass, Small Ruminant Research (2019), doi: https://doi.org/10.1016/j.smallrumres.2019.10.008

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier.

Running head: Inner Mongolian native grass form on growing sheep

Evaluation of the growth performance and meat quality of Mongolian lamb fed grass, hay or pellets of Inner Mongolian native grass

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S. Du a 1, S. H. You a 1, J. Bao1, Gegentu1, Y. S. Jia 1 *, Y. M. Cai 2 *

Key Laboratory of Forage Cultivation,Processing and High Efficient Utilization,

Ministry of Agriculture, P.R. of China, Key Laboratory of Grassland Resources,

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Ministry of Education, P.R. of China, College of Grassland, Resources and

Japan International Research Center for Agricultural Science (JIRCAS), Tsukuba,

Ibaraki 305-8686, Japan Corresponding author:

Yushan Jia,

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*

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2

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Environment, Inner Mongolia Agricultural University, Hohhot 010019, China

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College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot 010019, China

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Yimin Cai

Japan International Research Center for Agricultural Science (JIRCAS) 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan E-mail: [email protected]; [email protected] a

These authors contributed equally to this article and are co-first authors.

Highlights 

This is the first study of native grass type on Mongolian lambs.



Native grass pellet improved intake and palatability than that of hay.



The growth performance of lambs fed pellet same as of grass and better than hay.



Grass or pellet fed lamb improved the meat quality than that of hay.

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Abstract

The major constraint for livestock production in the Inner Mongolian Plateau is a feed

shortage in winter. The objective of this study was to compare and evaluate the growth

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performance and meat quality of juvenile Mongolian lambs fed Inner Mongolian native

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grass in three forms: grass, hay, or pellets. Sixty Mongolian non-castrated male lambs

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in good health of the same age (6 months) and with similar body weight (28.83 ± 0.19 kg) were randomly divided into three groups that fed Inner Mongolian native grass, hay

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or pellets (5 lambs per pen). Fresh grass intake was higher than pellets intake, and hay intake was lower than pellets intake (both P < 0.05). The lambs in the hay group

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exhibited daily weight loss, while the daily weight gains of the lambs in the grass and pellet groups were increased (P < 0.05). The carcass weight, body weight before

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slaughter, net meat mass, loin muscle area, and fat thickness (FT, a measure of fat tissue thickness) were greater (P < 0.05) in sheep given the grass and pellet groups than in those given the hay treatment. Compared with the hay treatment, the marbling score, water loss rate, and the protein were significantly increased in the grass and pellet groups, whereas the fat, Ca, a*, and b* values were significantly decreased. The results

indicate that feeding native grass or pellets is more beneficial than feeding Inner Mongolian hay for the growth performance and meat quality of Mongolian lambs.

Key words: lamb, Inner Mongolian native grass, hay, pellets, growth performance, meat quality 1. Introduction

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Native grasslands are distributed widely throughout the Mongolian Plateau and

are used predominantly for grazing and haymaking. The traditional production system for local livestock in pastoral areas includes grazing on pasture during the summer and

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feeding hay in pens during the winter (Schönbach et al., 2011). Given the seasonal and

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annual changes in the native grass supply, livestock become strong in summer, fat in autumn, and thin in winter and spring (Schönbach et al., 2011). In addition, with the

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development of the national economy and improvements in living standards, consumers’

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requirements for the quality of livestock products have increased (Ni et al., 2017). Thus, reliance on the traditional animal husbandry production model is causing an imbalance

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between supply and demand.

The major constraint for livestock production on the Mongolian Plateau is a

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shortage of feed in terms of quality and quantity, especially in winter and early spring. The major livestock feed sources are native grasses and agricultural by-products. Thus, livestock are fed low-quality roughage, resulting in low production. To help improve feed quality, pellets technology and applications have been developed and the adaptability of livestock to various conditions, nutritive value, and productivity have

been studied (O’Doherty et al., 2000; Abdollahi et al., 2013). Native grasses on the Mongolian Plateau typically grow well during summer (Kang et al., 2007) and should be preserved to support a continuous feed supply for ruminants in the other seasons. Hay and pellets preparation and storage are considered to be the most effective techniques to overcome winter shortages in the animal feed production system (Sun, 2005). Grazing during summer and feeding hay or pellets

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during winter are the main animal production methods on local farms; however, the types and characteristics of native grass and their impacts on livestock production on the Mongolian Plateau remain unclear.

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Therefore, the objective of this study was to compare and evaluate the growth

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performance, carcass characteristics, and meat quality of juvenile Mongolian sheep fed

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2. Material and methods

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native grass in three forms: native grass, hay, or pellets.

2.1 Animals and diets

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The study was conducted with sixty Mongolian non-castrated male lambs of good health with same age (6 months) and similar body weight (BW) of 28.83 ± 0.19 kg. The

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lambs were randomly divided into three dietary treatments fed native grass, native grass hay and pelleted grass. The experiment was lasted for 75 d, with 15 d for adaptation to the diets, and 60 d for the data and sample collection as well as the performance evaluation of the lambs. The lambs were fed with native grass in three forms (grass, hay, or pellets). The native grassland consisted of typical steppe flora of Xilinhot, Inner

Mongolian Plateau, including Giant Feather Grass (Stipa gigantea Link.), Krylov feathergrass (Stipa sareptana var. krylovii (Roshev.) P.C. Kuo et Y.H. Sun), Scabrous Cleistogenes (Cleistogenes squarrosa (Trin.) Keng), Common anemarrhena (Anemarrhena asphodeloides Bunge.), Chinese Leymus (Leymus chinensis (Trin.) Tzvel.), Mongolian Onion (Allium mongolicum Regel.), and Mongolian wheatgrass (Agropyron mongolicum Keng.) as the dominant species.

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The native grass was harvested at milk stage on August 15. After harvest, the

content of native grass was weighed, homogenized and subsampled. The chemical

composition was determined in duplicate for each subsample. The fresh native grass

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was divided to daily portions and frozen at -20℃ immediately. The daily portions were

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thawed at room temperature for 12 h before fed to lamb. In order to try and minimize the influence of chemical composition changes caused by forage growth, the hay and

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pellets were made in the same grassland at same time. For hay making, the grass was

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cut at a height of 5-8 cm with a tractor-mounted lawn mower. The grass was dried for about 72 h and tedded twice daily. The bander was baled when the moisture content

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reached 14%. Drying was performed under natural sunny conditions. Once the grass was dried, the hay was raked back into windrows and formed into square bales

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(60×50×40 cm, 15-17kg). Pellets were produced from the hay with a length of 2-3 cm by using a pellets machine (H.S. 508 Pellets Mill; Liyang Weifang Equipment Co Ltd., Liyang, China). After 5-day the hay and pellets was made, the feeding experiment was carried out. Lambs were provided grass, hay or pellets daily at 08:00 and 16:00 and water was

provided ad libitum throughout the experimental period. The native grass was thawed and took to the manager to feed the lambs, directly. The amount of salt (Shiyan, Inner Mongolia Salt Industry Co., Ltd., Xilinhot, China) was measured and dissolved into the drinking water of all groups, and a mineral block (Yuantong Weiye Feed Co., Ltd., Hohhot, China) was mounted on the wall of each pen on which lambs could lick and chew. The salt and the mineral block consumption were also ad libitum.

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Before the experiment, the shed in which the lambs were housed was disinfected with 3% sodium hydroxide and lime. The lambs were given albendazole (Shandong Youyi Animal Pharmaceutical Co., Ltd., Heze, China) as a deworming treatment.

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2.2 Chemical analysis

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Dry matter (DM) of native grass was measured after drying in the oven at 65°C for 48 h, grinding, and filtering through a 1 mm screen (FW100, Taisite Instrument Co.,

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Ltd., Tianjin, China) for chemical analysis. The chemical composition data on the DM

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were corrected for the residual moisture after 3 h at 105°C. The ash, crude protein (CP) and ether extract (EE) contents were determined by the methods of Association of

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Official Analytical Chemists (AOAC, 1994). The organic matter (OM) content was calculated as the weight loss upon ashing. The neutral (NDF) and acid detergent fibres

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(ADF) were determined using the method of Van Soest et al. (1991)

with an ANKOM

A200i fibre analyser (ANKOM Technology, Macedon, NY, USA) and were expressed exclusive of residual ash. The gross energy (GE), energy in feces (FE), energy in urine (UE) and energy in gaseous products of digestion (Eg) were analysed by the AOAC method using an Oxygen and Nitrogen Analyzer (IKA Works GmbH & Co., Staufen,

Germany). Metabolizable energy (ME) was calculated according to the method of Freer et al. (2007) using the following formula: ME = GE - FE - UE - Eg. 2.3 Feed intake and growth performance The quantity of grass, hay and pellets intake was measured for each group of lambs by weighing all feed offered during the experimental period and recording the number of daily meals refused. The intake of three groups was expressed on a DM basis. Lambs

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were weighed without fasting at the commencement and end of the 60-d experimental

period and at 14-d intervals, and the BW gain was calculated as the difference between

the final BW and the initial BW. Final BW was lambs' weight in the experimental farm

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before the lamb was transported to a commercial slaughterhouse.

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2.4 Carcass measurements

The lambs were slaughtered at the end of the experiment. Before being transported

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to the slaughterhouse, they were fasted for 12 h and had access to water all the time.

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The BW before slaughter was lambs' weight when they were re-weighed just before slaughtering in slaughterhouse. Immediately after arrival, they were stunned

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electrically and slaughtered by severing the jugular vein. Trotters, skin, blood, head, and gastrointestinal tract contents were removed. Carcasses were weighed 24 h after

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slaughter to determine cold carcass weight (after storage for 24 h in a cooler at 2 °C). The dressing percentage was carcass weight divided by live weight (MajdoubMathlouthi et al., 2013). Longissimus lumborum muscle samples were collected for further analysis from the carcass on the right side of the vertebrae and stored in a freeze at -20°C.

The meat and bones were separated from the body and used to calculate the net meat percentage (net meat mass/total carcass weight × 100). The lumbar loin muscle area (cross-sectional area of the longissimus lumborum) was used as a measure of meat quantity. The fat thickness (FT) was determined by measuring the tissue thickness between the 12th and 13th ribs, 1.1 cm from the midline, which is a metric of body fat. 2.5 Chemical composition and meat quality

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The moisture, protein, fat, ash, calcium, phosphorus, and cholesterol contents were determined following the methods of the American Organization of Analytical

Chemists (AOAC, 1994). The pH of the longissimus lumborum muscle was measured

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between the 11th and 13th ribs at 1 h (pH1) and 24 h (pH24) post-mortem by a glass

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electrode pH meter (STARTED 100/B, OHAUS, Shanghai, China). Marbling score was determined visually by making use of a pink plate standard (DeVol et al., 1985). The

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colour of loin subsamples was evaluated after blooming for 30 min using a Spectro-

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Guide 45/0 colorimeter (BYK-Gardner, Columbia, USA) to determine the L* (brightness), a* (red–green range), and b* (blue–yellow range) values. The water loss

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rate was determined by weighing a 1.5-cm loin sample, placing it in netting and suspending it in an inflated plastic bag. After storage for 24 h at 4°C, the sample was

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weighed again, and the drip loss was calculated as the percent weight lost relative to the original sample weight (Lawrie & Ledward, 2006). For the determination of cooking loss, a 1.5-cm loin subsample was weighed and placed in a thin-walled plastic bag in a water bath at 80°C. After 1 h, the cooked sample was removed from the water bath, cooled in cold water, blotted dry, and weighed. Cooking loss was calculated as

the percent weight lost relative to the initial sample weight. The meat tenderness of 1.27 cm-diameter samples from the same meat used for the cooking loss determination was measured in triplicate with a Warner-Bratzler shear head (Zhao 2011). Samples were randomly removed from the centre of each longissimus lumborum sample and cooled to 4°C. The maximum shear force (in kilograms) required to shear a cylindrical core perpendicular to the grain (at a crosshead speed of 200.0 mm/min) was recorded for

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each sample, and the mean value was calculated for each muscle. 2.6 Statistical analysis

The growth performance, carcass characteristics, and meat quality were analysed

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by one-way analysis of variance, and significant differences among treatment were at

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the 5% probability level (Steel & Torrie, 1980) using SAS ver. 9.0 (2007; SAS Institute,

2.7 Animal care

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Cary, NC, USA).

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The animal experiments were approved by the Committee of Animal Experimentation and were performed under the Institutional Guidelines for Animal

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Experiments of the College of Grassland, Resources and Environment, Inner Mongolian Agricultural University, China. The experiments were performed according

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to recommendations proposed by the European Commission to minimize the suffering of animals.

3. Results The chemical composition of the grass, hay and pellets used in this study is shown

in table 1. Grass, hay, and pellets had dry matter (DM) contents of 50.62%, 83.83%, and 82.88%, respectively. The crude protein, ether extract, organic matter, acid detergent fibre, and neutral detergent fibre contents of the three grass types were similar. Finally, the metabolizable energy values of grass, hay and pellets were 7.56, 7.49 and 7.53 MJ/kg DM, respectively. The ingredients and chemical compositions are shown in Table 2. The ingredients

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were composed of 99.96% native grass, hay, or pellets based on DM. Salt and mineral premixes were added, each accounting for 0.02% of the diets. The chemical compositions of the three grass types were similar.

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The intake, growth performance, and carcass characteristics are shown in Table 3.

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Native grass intake was significantly greater and hay intake was significantly lower than pellets intake. The initial BWs were similar, but the final BWs were significantly

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greater in the grass and pellet groups than in the hay group. The average daily weight

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gain of sheep fed hay was –58.67 g/d, whereas those of sheep fed grass and pellets were 80.00 g and 76.11 g/d, respectively. The carcass weight, BW before slaughter, and net

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meat mass were significantly greater in the grass and pellet groups than these in the hay group. The dressing percentage, bone mass, and net meat percentage did not differ

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among the treatments. The loin muscle area and FT were significantly greater in the grass and pellet groups than in the hay group. The chemical composition and quality of the meat are shown in Table 4. The moisture and ash contents of the muscle in the grass, hay, and pellet groups did not differ substantially. Compared with the hay group, the protein content was significantly

increased by more than 1.8 g/100 g in the grass and pellet groups. The phosphorus content was significantly increased by more than 33.5 mg/100 g in the pellet group compared with the grass and hay groups. The fat and calcium contents were significantly lower in the grass and pellet groups than in the hay group. The three groups had similar pH1, pH24, L*, cooking yield, and shear force values. The marbling score and water loss rate were significantly lower in the hay group than

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in the grass and pellet groups. The a* and b* values were higher in the hay group than in the grass and pellet groups. The hay and pellet groups resulted in similar cholesterol

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contents, which were significantly lower than that resulting from the grass treatment.

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4. Discussion

The major natural feed sources are native grasses on the Inner Mongolian Plateau.

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The grazing in summer and feeding hay in winter is the traditional style of local animal

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production. When livestock fed low quality roughage, resulting in low production. Pellets applications have been developed through the study of their nutritive value,

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productivity, and adaptability to various conditions (O’Doherty et al., 2000; Abdollahi et al., 2013). Many cattle and sheep owners have found that pelleting is an easier method

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of feeding animals because feed pellets are easy to handle, dispense, and store (O’Doherty et al., 2000). In the present study, the native grassland on the Inner Mongolian Plateau was used for this experiment, and the native grass, hay and pellets were prepared from the same grassland under natural conditions. In present study, the dominant grasses in the Inner Mongolian native grassland belong to Gramineae species.

Based on the quality and quantity of hay making, the best harvest stage of native grass was in the milk stage (Hou et al., 2017). Therefore, the quality of hay and pellets were high, and their chemical compositions therefore did not differ substantially. However, the intake of grass and pellets was better than that of hay. The higher grass intake may have been due to the palatability of fresh grasses. As shown in Table 1, the fresh grass used in this study had a moisture content of 49%. The fresh grass might have had a

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sweeter, more appealing flavour, stimulating the lambs’ appetites. In addition, the hay

and pellets did not have differences in nutrition or quality from the native grass. The major cause of the differences between the intake of hay and pellets may be the

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characteristics of dominant grass and pelleting process since the chemical composition

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was the same. Stipa is a dominant grass genus in Mongolian native grasslands, and the young leaves and stems in early spring and regeneration material in autumn are highly

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palatable (Yun et al., 2010). However, this grass has awn needles on the caryopses,

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which become hard and sharp at maturity, reducing the feed intake. The pellets used in this experiment were made from ground hay treated with heat, moisture, and extreme

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pressure and pressed through holes to form pellets. Pelleting is the process by which pellets mills compress hay into nutritionally balanced pellets for livestock feed.

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Therefore, the pelleting process might have improved the feed intake due to the increase in density and decrease in length and hardness. This result was consistent with the results reported by Wondra et al. (1995) and Behnke et al. (2004), who also found that pelleting had an improved effect on intake. Native grass is generally fresh and juicy, with a higher utilization rate and quality,

and can meet animal nutrient needs, resulting in an increased BW in summer (Fraser et al., 2009). In winter, hay is provided merely to sustain life, although the inclusion of alfalfa and Leymus chinensis hay in the diet can significantly increase BW gains because of the higher CP content and palatability (Grings et al., 1991; Kalscheur et al., 1999). Conversely, some native grasses have been seen to have negative effects on BW and growth performance (Szendrö et al., 2015). These factors are consistent with our

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results, as the hay group was resulting a negative daily weight gain (–58.67 g), likely due to the lower palatability and intake. Therefore, the alteration of the physical

morphology of grass is among the most effective ways to improve the palatability of

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feed and BW gain.

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According to the NRC (National Research Council, 1994), 6-month-old lambs, which have an estimated mature BW of 28 kg, gain weight at a rate of 85 g/d. In present

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study, the weight gain of lambs fed pellets (76 g/d) was close to this value. From the

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perspective of economic evaluation, the grass group had the best income effect. The cost of pellets production was higher than that of hay, but the economic income of the

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pellet group was higher than that of the hay group based on the daily weight gain of the lambs (Sun et al., 2017).

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Overall, from the perspective of animal health and growth, pellets is a good winter

feed for lamb growth, whereas native hay is not recommended. Silage is a good way to preserve quality and palatability of grass. Future research needs to study the effect of native grass silage on lambs production. In the present study, there was no significant difference on water. The result is in

accordance with Murphy et al. (1994) who studied the effect of pasture fed lambs. The meat protein content was greater and the fat content was lower in the grass and pellet groups than in the hay group. These differences might be the negative growth performance in hay group. When lambs fed with grass, hay and pellets, the available nutrients were used for the synthesis for fat and protein in the same way. In the hay group which lost weight, there are already signs of tissue catabolism in terms of lower

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muscle area, fat thickness and protein. Therefore, greater quantities of fat can be extracted from the meat as a result of catabolic processes and end products to provide

energy. On the other hand, the protein of grass and pellet groups required energy from

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fat reserves to maintain and the fat was broken down (Sève et al., 1997). Consequently,

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the meat protein content was greater and the fat content was lower in the grass and pellet groups.

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The pH is an important indicator of meat quality and is generally between 6.0 and

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7.0. After 1 h, the pH began to decline, although the pH1 and pH24 values did not differ substantially among the three groups. It is possible that lambs fed with grass, hay and

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pellets receive the similar energy and sufficient accumulation of glycogen in their muscle (Jacques et al., 2017, Priolo et al., 2001). The marbling score was higher in the

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grass and pellet groups than in the hay group. This result reflects that intake affected not only the fat and protein contents of meat but also the marbling score. These findings are also in agreement with those of Carvalho et al. (2000), Pires et al. (2000), and Silva et al. (2007). Marbling score is based on the level of intramuscular fat. The marbling score is thus related to the degree of fatness of the meat. Intake was considered to be

one of the important factors attributing to higher marbling scores (Adachi et al., 1999). The higher intake might improve marbling score because of the higher intake of carbohydrates which are stored as fat (Oka et al., 1998). The degree of fatness is enhanced by higher intakes of fresh and pellet groups compared to that of hay (Priolo et al. 2001). Therefore, the result indicated that the marbling score was greater in the grass and pellet groups.

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Meat L* values > 44 are considered to be acceptable by 95% of consumers, and

those < 34 are unacceptably dark (Khliji et al., 2010). The L* values were > 50, within the range of consumer acceptability, in all treatment groups. The effects of the feeding

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system and environment on these parameters remain unclear. In this study, the hay

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treatment resulted in lower intake than did the grass and pellet groups. Of these, intake was the main reason for the higher a* and b* values in the hay group relative to the grass

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and pellet groups (Sekali et al., 2016). Besides, the lower ADG could have potentially

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accumulated in their muscle as a possible explanation (Jacques et al., 2017). As shown in Table 4, meat from grass fed lambs had significantly higher

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cholesterol content than the meat from hay- and pellet-fed lambs. When animals fed grass, hay and pellets, unsaturated fatty acids are converted into saturated fatty acids in

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the rumen, improving cholesterol synthesis (Rule et al., 2002; Van Soest 1994). Intake of lambs fed fresh grass was higher than that of the other treatments. And so providing greater quantities of saturated fatty acids and resulting in higher cholesterol content of grass group (Schoonmaker et al., 2002). The water loss rate of grass and pellet groups was higher than hay group, which would be because of protein and fat. The fat has been

shown to have a greater percentage of water bindings (Jacques et al. 2017). The content of protein in grass and pellet groups was higher than the hay group while the content of fat was lower in these groups. Consequently, the grass and pellet groups had a higher water loss rate.

5. Conclusion

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This study revealed that Inner Mongolia native grass, hay, and pellets had various effects on growth performance and meat quality of Mongolian lambs. Compared with hay, pellets could improve the intake, growth performance, carcass characteristics, and

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meat quality. And the pellets had the similar effects on growth performance, carcass

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characteristics, and meat quality with grass. The pelleting process not only reduces the hardness of native grass, but improves the palatability for lambs. These results indicated

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that the use of native grass pellets as feed during winter or shortages could be

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considered to support lambs growth.

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Conflict of interest statement

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This work has no conflict of interest.

Acknowledgements This work was supported by the projects “National Key Research and Development Program (2017YFD0502103)”, Ministry of Science and Technology, China and “Correlation study on the hay drying mechanism and nutrient changes of native grass

from typical steppe after harvesting (31760710)”, National Natural Science Fund, China. We thank Xingde Farming and Animal Husbandry Co., Ltd (Xilin Hot, Inner

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Mongolia, China) for providing the Mongolian lambs.

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Table 1. Chemical composition of native grass, hay and pellets

Hay

Grass

Pellets

50.62b±0.17

83.83a±0.19

82.88a±0.23

8.58±0.62

8.17±0.47

8.42±0.44

4.58±0.32

4.49±0.27

4.52±0.22

Organic matter (% DM)

95.37±0.21

95.42±0.16

95.39±0.25

Acid detergent fiber (% DM)

40.69±0.90

41.64±1.64

41.17±1.06

Neutral detergent fiber (% DM)

55.52±0.23

56.92±0.64

55.69±0.37

7.56±0.14

7.49±0.09

7.53±0.18

Dry matter (DM, %) Crude protein (% DM) Ether extract (% DM)

Metabolizable energy (MJ/kg DM)

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Data are means of three samples, means ± SEM within rows with different superscript letters differ (P<0.05).

Table 2. Ingredients and chemical composition of diets Grass

Hay

Pellets

-

-

-

99.96

-

-

Hay

-

99.96

-

Pellets

-

-

99.96

Salt

0.02

0.02

0.02

Mineral premix

0.02

0.02

0.02

50.57b

83.86a

82.93a

Crude protein (% DM)

8.61

8.14

8.39

Ether extract (% DM)

4.55

4.43

4.52

Ingredient (% DM) Grass

Dry matter (%)

Acid detergent fiber (% DM)

40.73

Neutral detergent fiber (% DM)

55.42

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Chemical composition

41.24

41.17

56.52

55.73

DM, dry matter; Mineral were calculated values based on the commercial products. The levels of minerals in the premix were calculated based on the commercial products, which included 1600 mg/kg magnesium, 150 mg/kg

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cuprum, 400 mg/kg iron, 400 mg/kg manganese, 450 mg/kg zinc, 5 mg/kg cobalt, 15 mg/kg selenium and 60 mg/kg

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iodine.

Table 3. Intake, growth performance and carcass characteristics of Mongolian lambs Grass

Hay

Pellets

0.39c±0.01

Initial BW (kg)

29.00±0.47

28.60±0.43

28.60±0.24

Final BW (kg)

34.40a±0.84

24.88b±1.14

32.48a±1.39

Average daily gain (g/d)

80.00a±1.69

- 58.67b±17.33

76.11a±1.25

Carcass weight (kg)

15.85a±0.44

11.18b±0.33

15.20a±0.32

BW before slaughter (kg)

34.40a±0.84

24.08b±0.96

32.48a±1.39

Dressing percentage (%)

46.13±1.34

46.61±1.43

47.09±2.03

Net meat mass (kg)

13.07a±0.22

9.83b±0.30

13.29a±0.11

3.11±0.19

3.15±0.17

3.21±0.17

80.77±0.24

80.35±0.22

81.11±0.31

12.87a±0.10

11.15b±0.16

12.93a±0.51

Intake (kg, % DM)

Bone mass (kg) Net meat percentage (%) Loin muscle area

(cm2)

1.17a±0.17

FT (cm)

0.89b±0.01

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0.92a±0.01

1.03b±0.02

1.19a±0.02

Data are means of twenty sheep, means ± SEM within rows with different superscript letters differ (P<0.05). FT, fat

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thickness.

Table 4. Chemical composition and meat quality of Longissimus lumborum muscle in Mongolian lambs Grass

Hay

Pellets

Chemical composition Moisture (g/100g)

59.53±1.33

62.70±1.25

63.68±2.33

Protein (g/100g)

19.11a±0.12

17.20b±0.22

19.27a±0.14

Fat (g/100g)

22.06b±0.79

28.57a±0.44

22.60b±1.73

Ash (g/100g)

0.88±0.05

0.83±0.02

0.91±0.13

Calcium (mg/100g)

1.96b±0.01

2.53a±0.20

1.83b±0.06

149.35b±0.58

156.50a±1.67

190.02a±1.72

Phosphorus (mg/100g) Meat quality

6.32±0.24

6.29±0.13

6.28±0.19

pH24

5.89±0.21

5.85±0.22

5.87±0.19

Marbling score

3.27a±0.01

3.03b±0.02

50.94±2.14

52.42±14.62 2.31a±0.46

b*

1.29b±1.58

3.34a±1.87

29.97a±0.27

19.77b±1.95

6.11a±0.33

4.24b±0.41

5.88a±0.18

L*

Cholesterol (mg/100g)

Cooking yield (%)

3.25a±0.01

52.24±1.60

1.85b±1.10 1.47b±1.62

22.34b±0.46

64.90±1.61

62.62±2.03

65.24±0.99

4.28±0.52

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Water loss rate (%)

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a*

1.72b±0.90

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pH1

4.25±0.43

Shear force (kg)

4.21±0.22

Data are means of twenty sheep, means ± SEM within rows with different superscript letters differ (P<0.05). L*,

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lightness; a*, redness; b*, yellowness.