- Open Access
Effects of by-product feed-based silage on feeding, rumination, and excretion in growing Hanwoo heifers
© Kim et al.; licensee BioMed Central. 2015
Received: 19 September 2014
Accepted: 21 December 2014
Published: 27 January 2015
This study investigated the effects of feeding by-product feed (BF)-based silage on the behavior of growing Hanwoo heifers. Twelve Hanwoo heifers (13.2 months-old, 315 kg body weight; four heifers per pen) were assigned to three diets: a rice straw (RS) diet (concentrate mix and free access to RS), a RS and BF-based silage (RSBFS) diet (concentrate mix and free access to RS and BF-based silage), and a BF-based silage (BFS) diet (concentrate mix and free access to BF-based silage). Behavior was recorded for 5 days using camcorders. Compared to the RS group, the BFS group showed 21.7% higher dry matter intake, shorter feeding, rumination, and chewing times, as well as longer resting time (p < 0.05). Although all groups exhibited similar drinking, urination, and defecation frequencies, the BFS group exhibited higher feeding rates, rumination efficiency, and chewing efficiency than the RS group (p < 0.05). Compared to the BFS group, the RSBFS group showed higher peNDF8.0 intake (15.2% vs. 25.0% dry matter intake), longer feeding and sitting times, lower defecation frequency (p < 0.05), and similar rumination efficiency. In conclusion, complete replacement of conventional RS with BF-based silage reduced rumination and chewing activity in growing Hanwoo heifers, and BF-based silage feeding with large-particle straw is an effective approach in improving heifer behavior.
Demand for increased development of cheap domestic by-product feed (BF)-based roughage has increased in proportion to higher imported roughage and hay prices. Feeding of growing beef cattle with high quality roughage is an effective method of well-marbled beef . Specifically, beef steers fed high quality timothy hay [2,3], during the growing period show improved growth and meat quality, and replacement of low quality rice straw (RS) with proteinaceous timothy and alfalfa hay has been shown to increase body weight gain and produce well-marbled beef [4,5]. However, as a limitation, the price of timothy hay is twice that of RS.
In our previous study , cheap and high quality BF-based roughage was successfully manufactured by ensiling spent mushroom substrate (SMS), recycled poultry bedding (RPB), rice bran, minimal straw with added molasses, and highly cellulolytic microbes, which were isolated from the SMS . The silage exhibited favorable ensiling characteristics as well as higher degradability of dry matter (DM) and crude protein (CP) compared to RS or ryegrass straw . Substitution of conventional RS with BF-based silage, which has a physically effective neutral detergent fiber (peNDF)1.18 of approximately 35%, did not significantly affect the rumination behavior of Hanwoo steers . However, no information is yet available on the effects of BF-based silage on Hanwoo heifers.
A proper dietary level of peNDF is required to maintain the ruminal pH above 6.2. There are two types of peNDF, peNDF8.0 and peNDF1.18, and little information is available on which peNDF is more reliable for predicting rumination behavior in growing beef cattle.
This study was attempted to determine the effects of BF-based silage on feeding, rumination, resting, and excretion in growing Hanwoo heifers as well as the reliability of dietary peNDF8.0 and peNDF1.18 for predicting rumination behavior in growing beef cattle.
Animals and treatments
All animal care protocols were approved by the Konkuk University Institutional Animal Care and Use Committee. Twelve Hanwoo heifers with a mean age of 13.2 months and a mean body weight (BW) of 315 ± 1 kg were allocated to three pens (four heifers per pen). The area of each pen was 48 m2 (4 m × 12 m). Animals were fed one of three diets: a RS diet (concentrate mix and free access to RS), a RS and BF-based silage (RSBFS) diet (concentrate mix and free access to RS and BF-based silage), and a BF-based (BFS) silage diet (concentrate mix and free access to BF-based silage). Feed was supplied twice a day (07:00 and 18:00). All animals were fed 4.7 kg/d concentrate mix (normal commercial formulated feed) on a restricted basis, 0.45 kg/d alfalfa hay, with free access to fresh water. All heifers were acclimatized to their diets and housing for over 1 month before the experiment.
Manufacturing BF-based silage
Particle size distribution, physical effectiveness factors (pef), and physically effective fiber (peNDF) content of the feeds
BF-based silage 1)
% dry matter (DM) retained on sieves
Above 19.0 mm
Below 1.18 mm
peNDF8.0, % of DM
peNDF1.18, % of DM
Particle size determination
Particle sizes of the experimental feeds were measured using a Penn State Particle Separator, according to Kononoff and Heinrichs . The separator consisted of three sieves (1.18, 8, and 19 mm) that could separate feeds into four types by particle size. For the physical effectiveness factor (pef), the proportion of particles larger than 8 mm was considered to be pef8.0, according to Lammers et al. , and the proportion of particles larger than 1.18 mm was considered to be pef1.18, according to Kononoff and Heinrichs . The peNDF8.0 and peNDF1.18 were calculated by multiplying the NDF percentage by pef8.0 and pef1.18, respectively. For calculation of the concentrate mix pef1.18, the ratio of the corn flake portion to the other portions was determined. The pef values for the corn flake portion and the other concentrate mix pellets were 0.8 and 0.3, respectively, according to Metens . The particle sizes of RS, alfalfa hay, BF-based silage, and concentrate mix used in this experiment are presented in Table 1. Compared to RS, BF-based silage had much smaller particles and much lower pef and peNDF values.
Behavioral observation methods and analysis
Prior to the experiment, the animals were adapted to night lighting for 10 days. Three camcorders (SVR-450, Samsung, Korea) were installed outside of the pen edge, and data were recorded for 120 h at each of the three pens. Feeding, rumination, and resting times, together with frequencies of defecation and urination, were measured at 1-min intervals and recorded on plotting paper.
Feed intake was calculated by measuring the difference between the supplied and remaining amounts of feed, and the remaining ort was retrieved and measured before the next morning’s feeding. Chewing time was calculated by summing feeding and rumination times, and feeding, rumination, and chewing efficiencies were calculated by dividing voluntary DM intake by the respective feeding, rumination, or chewing times.
Chemical compositions of the feeds fed to growing Hanwoo heifers
BF-based silage 1)
%, DM basis
Neutral detergent fiber
Acid detergent fiber
Data were subjected to one-way analysis of variance (ANOVA) using the general linear model (GLM) procedure . Comparisons of means between RS, RSBFS, and BFS treatments were made using Tukey’s multiple range test , and significance was set at p < 0.05.
Results and discussion
Daily feed intake
Effects of feeding by-product feed-based silage on feed dry matter (DM) and neutral detergent fiber (NDF) intakes in growing Hanwoo heifers
Diet 1) with
Feed DM intake, kg/d
NDF intake, kg/d
% of DMI
peNDF8.0 intake, kg/d
% of DMI
peNDF1.18 intake, kg/d
% of DMI
NDF intake by the BFS group was 15% higher than that by the RS group. Feeding of the BFS group with BF-based silage resulted in increased feed NDF intake due to higher feed DM intake, although the NDF content of BF-based silage was 21.3% lower than that of RS. The proportion of NDF intake per DM intake was similar (40–42%) between treatments. These levels fully satisfied the minimum criterion of 25% dietary NDF, which is recommended for maintenance of normal ruminal pH . In general, rumination time increases as NDF content increases, which helps to maintain a normal ruminal pH [20,21].
Intake of peNDF8.0 decreased by 13.9% in the RSBFS group and by 37.6% in the BFS group. The reduced peNDF8.0 intake per DM intake in the BFS group was due to the large difference in pef8.0 between RS and BF-based silage (99.0% vs. 18.5%, respectively). The 15.3% peNDF8.0 intake per DM intake was just above the minimal 15% level for maintenance of ruminal pH above 6.0, as suggested by Beauchemin et al.  and Zebeli et al. . In the RSBFS group, peNDF8.0 intake per DM intake was higher than that of the BFS group.
The peNDF1.18 intake per DM intake (23–25%) decreased by 2–4% when hiefers were fed BF-based silage. It has been reported that peNDF1.18 intake per DM intake should be 30%  or 30–32%  for maintenance of ruminal pH above 6.2, whereas it should be at least 22.3% to maintain ruminal pH above 6.0 . In the present study, 23–25% peNDF1.18 intake per DM intake in the BF-based silage-fed groups was sufficient to maintain ruminal pH above 6.0 but insufficient to maintain ruminal pH above 6.2. Consequently, for prediction of rumination behavior, dietary peNDF8.0 intake seemed to be a more reliable index than dietary peNDF1.18 intake during the rumen-developing period of growing cattle, as also reported by Zebeli et al. .
Feeding, rumination, and resting
Effects of by-product feed-based silage on feeding, rumination, chewing, and resting in growing Hanwoo heifers
Diet 1) with
Per kg of DM
Per kg of NDF
Per kg of peNDF8.0
Per kg of peNDF1.18
Per kg of DM
Per kg of NDF
Per kg of peNDF8.0
Per kg of peNDF1.18
Per kg of DM
Per kg of NDF
Per kg of peNDF8.0
Per kg of peNDF1.18
Rumination time per dietary intake of DM, NDF, or peNDF1.18 was shorter in the BF-based silage groups than in the RS group (p < 0.05), despite higher dietary DM and NDF intakes. Okine and Mathison  reported that dietary NDF intake increases with rumination time. However, in the present study, BF-based silage feeding increased dietary NDF intake while reducing rumination time by 38–39% mainly due to decreased peNDF8.0 intake (up to 48%), which otherwise stimulates rumination activity. In the present study, the rumination time of 317.5 min/d in the BFS group is similar to the 322.5 min/d rumination time previously reported in Hanwoo steers (mean BW of 500 kg) fed a 40:60 ratio of RS and concentrate mix . This level is also higher than the 245.8 min/d rumination time of early fattening Hanwoo steers (491 kg BW) fed 1.1 kg of RS (12%) and 7.6 kg of concentrate mix (88%) , whereas it is lower than the 451 min/d rumination time of growing Hanwoo steers (357 kg BW) fed 2.7 kg of RS (33%) and 5.3 kg of concentrate mix (67%) .
The values for chewing time (feeding time plus rumination time) were highest in the RS group and lowest in the BFS group (p < 0.05), and chewing time per dietary DM or NDF intake was also lowest in the BFS group (p < 0.05). Similarly, Mertens  reported that as feed intake increases, chewing time per DM intake decreases since the amount of time that animals are able to chew per day is limited. In addition, Beauchemin et al.  reported that as peNDF1.18 intake increases, chewing time per kg of peNDF1.18 decreases, as partially confirmed in the present study. We found that 15.3% dietary intake of peNDF8.0 in the BFS group suppressed rumination and chewing activity.
BF-based silage feeding resulted in a longer resting time compared to RS (p < 0.05). Standing and sitting times were similar between the RS and BFS groups, whereas the RSBFS group spent more time sitting compared to the BFS group (p < 0.05).
Drinking and excretion
Effects of feeding by-product feed-based silage on drinking, urination, and defecation in growing Hanwoo heifers
Diet 1) with
Feeding rate, rumination efficiency, and chewing efficiency
Effects of feeding by-product feed-based silage on feeding rate, rumination efficiency, and chewing efficiency in growing Hanwoo heifers
Diet 1) with
Chewing efficiency was highest in the BFS group and lowest in the RS group (p < 0.05). Woodford et al.  and Ryu et al.  found that crushed and chopped feed with a small particle size reduces feeding time compared with feeds in their original form. Considering this, the increased chewing efficiency in the BF-based silage groups can be attributed to increased feeding rate and decreased feeding time. Therefore, the increase in feed DM intake by BF-based silage feeding can also be explained by improved feeding and chewing efficiencies. In a study by Lee et al. , wet total mixed ration feeding in a restricted or ad libitum manner resulted in elevated feed intake, followed by increases in feeding, rumination, and chewing efficiencies. These phenomena can improve the ruminal environment for enhanced animal productivity.
In conclusion, compared to RS, ad libitum BF-based silage feeding resulted in higher feed DM and NDF intake, shorter feeding, rumination, and chewing times, longer resting times (p < 0.05), as well as higher feeding, rumination, and chewing efficiencies (p < 0.05). Both groups exhibited similar frequencies of defecation, urination, and drinking. Compared to only ad libitum BF-based silage feeding, RS and BF-based silage together resulted in higher peNDF8.0 intake (15.2 vs. 25.0% of DMI, respectively), longer feeding and sitting times, lower defecation frequency (p < 0.05), and a similar rumination efficiency.
Dietary peNDF8.0 intake level was a better predictor of rumination behavior in growing Hanwoo heifers than dietary peNDF1.18 intake, and the complete replacement of conventional RS with BF-based silage depressed rumination activity. BF-based silage feeding with large-sized particle straw is an effective way of improving the behavior pattern of growing Hanwoo heifers.
This study was carried out with the support of the “Cooperative Research Program for Agriculture Science and Technology Development (Project No. PJ009382012015)”, the Rural Development Administration, Republic of Korea.
- Sainz RD, De la Torre F, Oltjen JW. Compensatory growth and carcass quality in growth-restricted and refed beef steers. J Anim Sci. 1995;73:2971–9.PubMedGoogle Scholar
- Matsumoto D: Fattening management program of black haired Hwawoo. In: Beef Cattle – Production and Veterinary Medicine System. Japanese Agricultural, Forestry and Fishery Culture Association. 1999:75–83.Google Scholar
- Kim BK. Effects of feeding high quality roughage (timothy hay) during growing period on growth performance and carcass characteristics of Hanwoo steers. Korean J Food Sci Anim Resour. 2006;26:212–7.Google Scholar
- Kim SI, Jung GG, Kim JY, Lee SW, Baek KH, Choi CB. Effect of feeding high quality hay on performance and physico-chemical characteristics of carcass of Hanwoo steers. Korean J Anim Sci Technol. 2007;49:783–800.View ArticleGoogle Scholar
- Oh YG, Nam IS, Choi CW, Baek KH, Kim JH, Kim DH, et al. Effects of different levels of CP intake on protein utilization and N excretion in varying growth stages of Hanwoo steers. Korean J Anim Sci Technol. 2007;49:369–78.View ArticleGoogle Scholar
- Kim YI, Oh YK, Park KK, Kwak WS. Ensiling chracteristics and the in situ nutrient degradability of a by-product feed-based silage. Asian-Aust J Anim Sci. 2014;27:201–8.View ArticleGoogle Scholar
- Kim YI, Jeong SH, Seok JS, Yang SY, Huh JW, Kwak WS. Isolation and identification of hydrolytic enzyme-producing bacteria from spent mushroom substrate. Korean J Anim Sci Technol. 2008;50:713–20.View ArticleGoogle Scholar
- Kim YI, Lee SM, Park KK, Kwak WS. Effect of feeding by-product feeds-based silage (Biosilage) on behavior pattern of growing Hanwoo steers. J Kor Grassl Forage Sci. 2013;33:290–7.View ArticleGoogle Scholar
- Kononoff PJ, Heinrichs AJ. The effect of reducing alfalfa haylage particle size on cows in early lactation. J Dairy Sci. 2003;86:1145–457.Google Scholar
- Lammers BP, Buckmaster DR, Heinrichs AJ. A simple method for the analysis of particle size of forage and total mixed rations. J Dairy Sci. 1996;79:922–8.PubMedView ArticleGoogle Scholar
- Mertens DR. Creating a system for meeting the fiber requirements of dairy cows. J Dairy Sci. 1997;80:1463–81.PubMedView ArticleGoogle Scholar
- AOAC (Association of Official Analytical Chemists). Official methods of analysis. 17th ed. Association of Analytical Chemists: Washington DC, USA; 2000.Google Scholar
- Van Soest PJ, Robertson JB, Lewis BA. Methods for dietary fiber, neutral detergent fiber, nonstarch polysaccharides in relation to animal nutrition. J Dairy Sci. 1991;74:3583–97.PubMedView ArticleGoogle Scholar
- Statistix7: User’s manual. Analytical Software, Tallagassee, FL, USA; 2000.Google Scholar
- Kato K, Kajima Y, Odashima M, Lee LS, Nam KT, Chiga H, et al. Feed passage and digestibility in Japanese deer and sheep. Research Report of Kawatabi Experimental Station. 1989;5:59–62.Google Scholar
- Jeon BT, Moon SH, Kwon YJ, Kwak WS. Effect of supplementary level of fermented broiler litter on the dry matter intake, digestibility and nitrogen balance in female spotted deer (Cervus Nippon). Korean J Anim Sci. 2001;43:730–1.Google Scholar
- Martz FA, Belyea RL. Role of particle size and forage quality in digestion and passage by cattle and sheep. J Dairy Sci. 1986;69:1996–2008.PubMedView ArticleGoogle Scholar
- Kim CM, Lee BS, Chung TY. Influence of cutting length of ammoniated barley straw on the eating and ruminating behavior of Korean native cattle. Korean J Anim Sci. 1994;36:487–93.Google Scholar
- NRC. Nutrient requirements of dairy cattle. 7th ed. Washington, DC, USA: National Academy Press; 2001.Google Scholar
- Woodford JA, Jorgensen NA, Barrington GP. Impact of dietary fiber and physical form on performance of lactating dairy cows. J Dairy Sci. 1986;69:1035–47.PubMedView ArticleGoogle Scholar
- Beauchemin KA, Buchanan S. Effects of dietary neutral fiber concentration and supplementary long hay on chewing activities and milk production of dairy cows. J Dairy Sci. 1989;72:2288–300.PubMedView ArticleGoogle Scholar
- Beauchemin KA, Yang WZ, Rode LM. Effects of particle size of alfalfa-based dairy cow diets on chewing activity, ruminal fermentation, and milk production. J Dairy Sci. 2003;86:630–43.PubMedView ArticleGoogle Scholar
- Zebeli Q, Tafaj M, Weber I, Dijkstra J, Steingass H, Drochner W. Effects of varying dietary forage particle size in two concentrate levels on chewing activity, ruminal mat characteristics and passage in dairy cows. J Dairy Sci. 2007;90:1929–42.PubMedView ArticleGoogle Scholar
- Zebeli Q, Mansmann D, Steingass H, Ametaj BN. Balancing diets for physically effective fibre and ruminally degradable starch: a key to lower the risk of sub-acute rumen acidosis and improve productivity of dairy cattle. Livestock Sci. 2010;127:1–10.View ArticleGoogle Scholar
- Zebeli Q, Tafaj M, Steingass H, Metzler B, Drochner W. Effects of physically effective fiber on digestive processes and milk fat content in early lactating dairy cows fed total mixed rations. J Dairy Sci. 2006;89:651–68.PubMedView ArticleGoogle Scholar
- Okine EK, Mathison GW. Effects of feed intake on particle distribution, passage of digesta, and extent of digestion in the gastrointestinal tract of cattle. J Anim Sci. 1991;69:3435–45.PubMedGoogle Scholar
- Lee WS, Lee BS, Lee SC, Lee SS, Lee SY, Lee DY, et al. Effects of rice straw and rice hull supplement on rumination and chewing behavior in Hanwoo steers. Kor J Anim Sci and Technol. 2004;46:49–54.View ArticleGoogle Scholar
- Lee SM, Kim YI, Kwak WS. Effect of by-product mixing silage feeding on the eating and ruminating behavior of Hanwoo steer. J Kor Grassl Forage Sci. 2010;30:159–68.View ArticleGoogle Scholar
- Lee SM, Hwang JH, Yoon YB, Kwak WS, Kim YI, Moon SH, et al. Effects of spent mushroom substrates addition on eating behavior of growing Hanwoo. J Kor Grassl Forage Sci. 2008;28:107–18.View ArticleGoogle Scholar
- Ryu YW, Ko YD, Lee SM. Effects of feeding rice straw silage made with apple pomace, sesame oil meal and cage layer excreta on growth rate, eating behavior and economical efficiency in Korean native cattle. Korean J Anim Sci. 1998;40:235–44.Google Scholar
- Jeon BT, Park IH, Lee SM, Moon SH, Kim KH, Kim JS, et al. The effects of different fiber sources on chewing behavior of Korean native cattle. Korean J Anim Sci. 1997;39:383–90.Google Scholar
- Balch CC. Proposal to use time spent chewing as an index of the extent to which diets for ruminants possess the physical property of fibrous characteristic of roughages. Br J Nutr. 1971;26:383–92.PubMedView ArticleGoogle Scholar
- Lee SM, Kim YI, Oh YK, Kwak WS. Effects of feeding methods of total mixed ration on behavior patterns of growing Hanwoo steers. Asian-Aust J Anim Sci. 2010;23:1469–75.View ArticleGoogle Scholar
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