Go to Top Go to Bottom
Anim Biosci > Volume 36(10); 2023 > Article
Risyahadi, Martin, Qomariyah, Suryahadi, Sukria, and Jayanegara: Effects of dietary extrusion on rumen fermentation, nutrient digestibility, performance and milk composition of dairy cattle: a meta-analysis



The present study aimed to evaluate the effects of extruded and unextruded feeding on the performance, milk composition, digestibility and ruminal fermentation of dairy cows through a meta-analysis.


The database was compiled from 53 studies in Scopus and PubMed. The data were analyzed using a random effects model in OpenMEE software. Extruded feed was grouped as the experiment group while and the others as control group. The bias of publication in the main parameter of dairy performance was evaluated by a funnel plot.


The result showed that extruded feed enhanced the milk yield, dry matter and crude protein digestibility, butyrate and valerate acid production (p<0.05). Meanwhile, the extruded feed significantly decreased the milk fat and protein concentration (p<0.05). Also, the iso-butyrate and iso-valerate in unextruded feeding was significantly higher than the extruded feed (p<0.05).


It was concluded from the meta-analysis that extruded feed effectively improved the milk production and milk lactose concentration, dry matter and protein digestibility, but not the milk fat and protein concentration.


Grains are used as either energy or protein sources for dairy animals. Protein source from grains is desirable because of its optimal amino acid profile, high digestibility and palatability while cereal grains contain high metabolizable energy. Nevertheless, several grains contain anti-nutrients which can reduce availability of nutrient and hamper animal performance [1,2]. Generally, various studies confirm that grain processing is required to minimize the amount of the anti-nutritional factors and some grains i.e., treated corn and sorghum are more resistant to rumen fermentation [3,4]. One of the techniques uses heat processing such as extrusion. This process has been associated with increased efficiency of fermentation by altering the protein matrix of the endosperm and the starch structure, thus allowing a better utilization by microbial enzymatic digestion. Yet, the consequence of extrusion process is protein denaturation which occurs in protein because of its highly reactive functional groups [5]. Therefore, extrusion cooking may additionally change molecular systems, weight and size of proteins which may be result in changes to crude protein (CP) sub-fractions.
Extrusion of grain involves using moisture, high temperature and pressure to reach a high stage of starch gelatinization. Also, those modifications might also have an effect on the palatability and standard the feeding price of the final product for ruminant feed. Temperature and heating duration must be carefully controlled for grains with high protein to optimize the digestible protein content and prevent the increasement of undigestible protein fraction or heat damage. Furthermore, the overprotection of protein can occur if the temperature is too high and thereby reducing the intestinal digestibility [6]. It has previously been shown that extruded feeding supplements reduced methane production and yield of lactating dairy cows, but dry matter intake (DMI) and milk yield have been additionally reduced [7,8].
Though many experiments have reported the effect of extruded grains in dairy performance and digestibility, there is no work to summarize those research results quantitatively and a meta-analysis of the effect of extruded feeding on dairy cows has not been conducted. This indicates that further study of extrusion on grain or feed in term of enhancing dairy cows’ performance and production is needed. The quantitative evaluation of input (unextruded and extruded feed) and output (performance, milk quality, digestibility and ruminal fermentation) by random effect meta-analysis method statistical approach might allow for assessing the relationships. Thus, the objective was to evaluate the effects of both extruded and unextruded feed on the dairy cow performance, milk composition, digestibility and ruminal fermentation by using meta-analysis method.


Literature search and selection criteria

A database was developed from several types of literature which reported the utilization of extruded feed on dairy cow. The searching of literature was conducted using Scopus and PubMed and the keywords used were ‘extruded’, ‘dairy’, and ‘cow/cattle’. The database was made in December 2022 from the Scopus research database while the PubMed research database was built up in January 2023. The initial search resulted in 359 articles with the selection criteria were: i) English-language articles; ii) direct comparison between extruded and unextruded feed; iii) the studies were conducted on dairy cattle; iv) comparison on animal performance, milk composition, digestibility and ruminal fermentation and; v) replication and variance were reported (standard deviation or standard error of the means). These criteria followed the Preferred Reporting Item for Systematic Reviews and Meta-Analysis (PRISMA) protocol.
The selection process is shown in Figure 1. Concisely, the initial search was screened based on the title. A total of 14 articles was excluded for several reasons (non-related title, review articles or conference proceedings). In abstract screening, the useful literature consisted of 241 articles and the rest were excluded because duplication, irrelevant contents or variables and animal type. Hence, the full text evaluation resulted in 61 articles while 180 articles were excluded due to lack comparison (n = 42), conference and review articles (n = 13), irrelevant contents or variables (n = 124) and different animal type (n = 1). The final articles (n = 53) after assessment consider as database in meta-analysis (Table 1).
A fail-safe number (Nft) was intended to recognize the publication bias caused by the insignificant studies which were not included on the analysis. Nft > 5N + 10 was considered to provide evidence of a robust meta-analysis model. Nft was calculated using Rosenthal et al’s method. The least sample size from individual studies was applied as N. Moreover, funnel plot was conducted to assess the publication bias.

Database development

The bibliography, animal breed, body weight (BW), age, extrusion process and feed ingredients were inputted to Microsoft Excel spreadsheet. Response variables included in database consisted of four groups, i.e., dairy performances (DMI), BW, body condition scoring (BCS), milk yield, and 4% fat-corrected milk (FCM) yield, milk composition (milk lactose concentration, milk fat concentration, and milk protein concentration), digestibility (dry matter digestibility [DMD], organic matter digestibility, crude protein digestibility [CPD], neutral detergent fiber [NDF] digestibility, and acid detergent fiber [ADF] digestibility) and ruminal fermentation (total volatile fatty acid [VFA], acetate acid, propionate acid, butyrate acid, iso-butyrate acid, iso-valerate, and valerate). The entire variables were converted into the same units of measurements. The descriptive statistics of database is presented in Table 2.

Data analysis

All data were analyzed using the random effects meta-analysis method. The calculation was based on the standardized mean difference of Hedges’ where the mean value of unextruded feed was grouped into control group (XC) and the mean value of extruded feed was the experimental group (XE). The calculation as followed:
J was the correction factor for the small sample size while S was the pooled standard deviation. The equation was derived from Sánchez-Meca and Marín-Martínez [9] with 95% confidence interval. The data were analyzed by using OpenMEE application for dairy performance (5 items), milk composition (3 items), digestibility (5 items) and ruminal fermentation (7 items).


Due to conflicting research findings and small sample size, not all results could be considered reliable due to publication bias. The funnel plot of milk yield as the main parameter in dairy performance showed in Figure 2. Briefly, the fail-safe number (Nfs) indicated which studies were suitable to be included into the final strong conclusions. This number expressed how many sample study sizes should be added in order to change the initial effect size into a negligible variable. If Nfs > 5N + 10, where N was the study effect size used to calculate the initial effect size, then the result could be considered as the final robust conclusion [10]. According to these fail-safe number rules, robust parameters of milk production included milk yield, milk fat concentration, milk protein concentration, milk lactose concentration, CPD, iso-butyrate and iso-valerate fatty acid.
This meta-analysis study used Q statistics test, τ2 and I2 to examine heterogeneity. The Q-statistic was the weighted sum of the squared values of each study effect size’s deviation from the mean effect size of all studies. The estimate of the population variable tau (τ) was the standard deviation of the overall effect size and τ2 represents the variance of the overall effect size. The I2 index was a measure of the proportion of unexplained heterogeneity. Based on Heterogeneity Q statistics test, τ2 and I2 showed that some variables were categorized in high heterogeneity and others was low heterogeneity. In terms of dairy performance, DMI and Milk yield had excess heterogeneity when Q was higher than degree of freedom (NC-1) meanwhile BW, BCS, and 4% were categorized in low or no excess heterogeneity when Q was lower than degree of freedom (NC-1). For milk composition and ruminal fermentation, all of variables were high heterogeneity. In term of digestibility only ADF digestibility had no excess heterogeneity. Heterogeneity was impacted by several factors the number of studies in the meta-analysis, how much the study effect sizes varied from each other (between studies variance) and how much variance existed in the observed effect size for each study (within-study variance) [11]. Heterogeneity of this study was high due to different type of ingredient, extrusion process parameter, dairy cow ages and the concentration of extruded feed. The differences of heat extrusion processes influenced quality of extruded feed so it affected the digestibility. Nutrient intake and total-tract apparent digestibility in dairy cows fed diets containing extruded soybean meals (SBM) produced by low and high temperature were different [12]. Different concentrations of extruded feed ingredients affected milk composition. Providing high doses of extruded linseed could also have negative effects on end product processing, such as generating important material losses during the churning stage [13].
A meta-analysis results are shown in Table 3 and 4. Table 3 shows the detailed meta-analysis results of dairy performance and milk composition according to Cohen’s methodology. In comparison to unextruded feed, feed extrusion significantly increased the milk production (p<0.05) while the other parameters were unaffected by extrusion cooking. On the other hand, extruded feed decreased DMI and 4% FCM yield percentage (p<0.05). For body weight and body score condition, no significant effect of the extruded process was observed. In term of milk composition, extrusion cooking significantly contributed to increasing the milk lactose composition (p<0.05). On contrary, the other compositions such as milk fat and milk protein were higher in unextruded feed (p<0.05).
Based on the ruminal fermentation, the meta-analysis results of digestibility and production of VFA of feed extrusion are presented in Table 4. It was indicated that dry matter and CPD was significantly higher for extruded feed (p<0.05). The digestion of organic matter and fibrous fraction (NDF and ADF) were not significantly affected by the extrusion process. Moreover, extrusion cooking also influenced the production of VFA. Butyrate and valerate production were enhanced in extruded feed (p<0.05) while the iso-butyrate and iso-valerate were significantly increased in unextruded feed (p<0.05). The production of total VFA, acetate and propionate for both control and experimental group were not significantly affected.


Effects on dairy performance and milk composition

Milk production was one of the dairy performances that was significantly affected. Increased in milk yield was also reported by Mendowski et al [6]. The reduction in DMI, but without an affect on milk production also reported by Kozerski et al [14], increasing starea in concentrate reduced daily DMI without affecting milk yield and 4% FCM yield. Contrary to reports that non protein nitrogen reduced DMI and consequently milk production [15,16]. When the partial replacement of SBM with urea did not affect milk production while maintaining DMI the maintenance needs and production of metabolizable proteins were mainly met by microbial protein synthesis [17]. The extruded feed material is very stably different in density and therefore ferments at different positions in the rumen and giving the duodenal starch a distinct appearance pattern. Income issues might be related to this size and physical shape of extruded pellets and use of smaller pellets may have solved the problem of extruded barley feed [18]. Due to the relative increase in the proportion of propionic acid, acetate content increased starch breakdown in the rumen [19]. A higher proportion of acetate than propionate causes milk production to increase, because acetate is a precursor to milk production. In addition, extruded feed lowers its density so the cows might digest it more slowly. Lower grain density is a possible explanation for the decrease in DMI [20].
Feeding an extruded ration affected the milk lactose concentration, milk fat concentration and milk protein concentration. Decreased milk lactose concentration, milk fat concentration and milk protein concentration were also reported by Mendowski et al [6]. Extruded feed would decrease the lipids supplied by blends, and in fact extrusion increased their availability in the rumen. Extruded affects the milk lactose concentration, milk fat concentration and milk protein concentration was also reported by Shabi et al [20]. When the cows were given ground corn feed it increased the frequency of eating but did not result in changes in milk protein or energy efficiency of milk, on the other hand if extruded feed was given, there was an increase in feeding frequency and a change in milk protein.
In addition, extruded increased the milk lactose concentration, milk fat concentration and milk protein concentration as reported by Nocek and Braund [21], Yang and Varga [22], and Chouinard et al [23]. This difference might be due to the influence of the temperature used in the extrusion process. In addition, heating oil produced reducing agents that were capable of capturing hydrogen ions and possibly inhibited methanogenesis in the rumen. Reduced methanogenesis spares other hydrogen ions for the production of propionate, which leads to milk fat depression [24]. Furthermore, extrusion of grains in high dietary concentrate fed to dairy cows affected the lactose percentage [25]. The lactation curve of lactose percentage showed a strict correlation with milk yield. In fact, the amount of absorbed water in the alveoli was determined by lactose and it affected the volume of produced milk [26]. This meta-analysis showed a linear result in which increased lactose concentration resulted in increased milk yield.

Effects on digestibility and ruminal fermentation

Extrusion feed affected the dry matter and CPD. Higher DMD was also reported by Berenti et al [27] and Gonthier et al [28]. This might be due to the digestion of CP. Increased CPD due to extrusion was proven in this meta-analysis work. Grain heat processing changed functional properties of its proteins, which in turn altered protein digestibility. The complex protein was broken down into small proteins such as peptides and this form was easier to digest by the animal [29]. During high temperature extrusion cooking, there was a decreasing of stable protein structures, and consequently polypeptides and peptides would be more available and more hydrolysable by digestive enzymes [30,31]. Moreover, alteration in protein fractions, molecular structural make-up and molecular weights might lead to changes in rumen undegradable protein (RUP) and rumen degradable protein fractions in adult ruminants. Samadi and Yu [5] reported heating process could enhance intestinal digestibility of RUP so it could improve the feed efficiency. Moreover, extrusion reduced the anti-nutritional factor in grains, such as kunitz domain/protease inhibitors in soybean, so the availability of protein increased [32]. Yet, higher temperature of extrusion could lead an overprotection of diet protein and reduced available amino acid in the intestine [6] although extrusion has been shown to improve true N digestibility [33,34].
Over processing would result in protein denaturation and most likely transform the proteins to a more resistant structure and cross-linkages formation between amino acids and reducing sugars such as Maillard reaction could occur. The effect of processing method on protein quality of feed might be more important and easier to detect in young dairy calves than in older calves because of their less developed gastrointestinal tract [1]. Despite an increase of CP digestibility which tended to increase post ruminal flow of microbial non-ammonia nitrogen (NAN), this did not result in an enhancing in milk protein concentration, which would suggest that the greater CP digestibility and microbial NAN flow might not necessarily result in a greater AA supply to the mammary gland [35].
Extrusion cooking did not affect the total VFA, acetate and propionate, yet other VFA i.e., butyrate, valerate, iso-butyrate and valerate were impacted. Among VFA, valerate and butyrate have a greater role in papillae development in the rumen [36,37]. Moreover, absorption of VFA might be related with ruminal papillae surface area, which would allow greater VFA diffusion transport through rumen tissue. Difference in ruminal butyrate and valerate concentration might have influenced the blood flow rate, which was also related with VFA uptake [3840]. In contrast, the iso-butyrate and iso-valerate were higher in unextruded feed. As a reverse form of butyrate and valerate, the iso-butyrate and iso-valerate production might be higher when the reverse form was lower.


The current research revealed that extrusion of grain affected the milk production and digestion of dairy cattle. In term of milk composition, extrusion could increase the lactose concentration, still the fat and protein concentration were significantly lower. The extruded feed could increase the dry matter and crude protein digestibility. Production of butyrate and valerate was increasing in extrusion feed while the iso-butyrate and iso-valerate were higher in unextruded grains.



We certify that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript.


Funding by IPB University is gratefully acknowledged with grant number 10291/IT3.L1/PT.01.03/P/B/2022.

Figure 1
Flow chart of articles selection process based on Preferred Reporting Item for Systematic Reviews and Meta-Analysis (PRISMA) protocol.
Figure 2
Funnel plot for milk yield.
Table 1
Articles included in the meta-analysis
No. Reference Experiment Animal breed Initial body weight (kg) Age (d) Extrusion heat (°C) Feed ingredients
1. [41] In vivo Holstein NA 116.00±64.00 DIM 120 Linseed
2. [42] In vivo Friesian 155.00
NA 90 Corn
3. [43] In vivo
In situ
Holstein NA NA NA Soybean
4. [44] In vivo
In situ
Friesian NA 80.00±41.00 DIM NA Soybean
5. [45] In situ Chilean Holstein NA NA 140 Dehulled lupin
6. [46] In vivo
In situ
Holstein 650.00±23.00 45.00 – 50.00 DIM 195 Whole horse bean
7. [27] In vivo
In situ
Holstein 40.30±0.63 1 of birth 150±2 Soybean meal
8. [47] In vivo Holstein NA NA 152 Whole cottonseed
9. [48] In vivo
In situ
Holstein 616.00 91.00 DIM NA Pima cottonseed cake
10. [49] In vivo Holstein 550.00 65.30 DIM 141 Soybean meal
In situ 65.70 DIM
11. [50] In vivo Holstein NA 43.00±23.00 DIM 150 Full-fat soybean
12. [51] In vivo Holstein 672.00±54.00 213.00±40.00 DIM NA Linseed – wheat
13. [23] In vivo
In situ
Holstein NA 35.00±10.00 of postpartum 120
14. [35] In vivo Holstein 712.00±54.00 90.00±31.00 DIM 160 WDDGS – pea
In situ 161 WDDGS – canola meal
15. [52] In vivo Italian Holstein NA 99.00±55.00 DIM NA Corn
16. [53] In vivo Holstein NA NA 105 Sorghum
118 Soybean
17. [54] In vivo Holstein 644.00±40.00 NA 120 Linseed
18. [55] In vivo
In situ
Holstein 548.10±66.90 74.00±12.00 DIM NA Canola seed
19. [56] In vivo
In situ
Holstein – Friesian 610.00 90.00 142 Rapeseed
20. [57] In vivo Holstein 648.00±46.00 61.00±4.00 DIM NA Linseed
Montbeliardes 646.00±51.00 76.00±5.00 DIM
21. [58] In vivo Friesian 546.00 NA NA Pea
22. [12] In vivo Holstein 650.00±54.70 141.00±31.00 DIM 149 Soybean meal
In situ 171
23. [28] In vivo Holstein 595.00±32.00 225.00±17.00 DIM 155 Flaxseed
24. [59] In vivo Holstein 595.00±32.00 225.00±17.00 DIM 155 Flaxseed
25. [60] In vivo Holstein NA −15.00 of postpartum 149 Soybean
26. [61] In vivo Holstein 565.00±54.00
21.00±3.00 of postpartum 160 Soybean meal
27. [62] In vitro NA NA NA 149 Soybean
28. [63] In vivo Holstein 565.00 21.00 of postpartum NA Soybean
29. [64] In vivo Lithuanian Black-and-White 590.00±20.00 30.00±6.00 DIM 135 – 155 Faba bean
30. [65] In vivo Danish Holstein 655.00±57.00 209.00±98.00 DIM 90 Wheat
115 Wheat – Soybean meal Maize
Maize – Soybean meal
31. [8] In vivo Holstein 672.00±54.00 213.00±40.00 DIM NA Linseed
32. [66] In vivo Italian Holstein 604.00±109.00 140.00±25.00 DIM NA Pea
33. [6] In vivo Holstein 754.00±58.00 65.00±21.00 DIM 140 Faba bean – Linseed
160 Lupin seed – Linseed
34. [67] In vivo Holstein 690.00±29.00 96.00±27.00 DIM 140 Fava bean
35. [68] In vivo Holstein 712.70±92.30 116.50±17.50 DIM NA Flaxseed – Pea
Flaxseed – Fava bean (containing tannin)
36. [69] In vivo Holstein 713.00±50.00 NA 155 Flaxseed
37. [70] In vivo Holstein 450.00 NA 116
Whole soybean
38. [71] In vivo Holstein 660.00±55.00 119.00±23.00 DIM NA Canola meal
In situ 694.00±56.00 220.00±71.00 DIM
39. [72] In vivo Holstein 584.00±15.00 14.00 of postpartum 140 Pea
40. [73] In vivo Holstein
Brown Swiss
NA NA NA Soybean
41. [74] In vivo Holstein NA 106.00±49.70 DIM 121 Corn
42. [75] In vivo Holstein 534.00±52.00 104.00±5.00 DIM NA Soybean
43. [76] In vivo Holstein NA 91.00 DIM NA Soybean/soybean meal
44. [77] In vivo Holstein NA 121.00±5.00 DIM NA Soybean
In situ 112.00±11.00 DIM
45. [20] In vivo
In situ
Holstein NA 103.00±20.00 DIM 200 Corn
46. [78] In situ Holstein 558.00±14.00 NA 140 Whole soybean
Soybean meal
Whole soybean – maize
47. [79] In vivo Holstein 575.00 112.00±15.00 DIM 130 Soybean meal
48. [80] In vivo Holstein NA 70.00 DIM 150 Soybean
49. [81] In vivo Holstein NA 189.00±57.00 DIM NA Soybean
Brown Swiss 126.00±49.00 DIM
50. [82] In vivo
In situ
Chinese Holtein 596.00±19.00 150.00 DIM NA Soybean
51. [83] In vivo Holstein 42.00±0.50 1 of birth NA Full-fat soybean
52. [84] In vivo Holstein NA 7 of birth 120 Corn
53. [85] In vivo
In vitro
Holstein NA 36.00 DIM NA Soybean

DIM, day in milk; WDDGS, wheat dried distillers’ grains with soluble.

Table 2
Descriptive statistics of database
Variables Unit NC Mean Min Max SD

Unextruded Extruded Unextruded Extruded Unextruded Extruded Unextruded Extruded
Dairy performance
 Dry matter intake (DMI) kg/d 84 16.37 16.21 0.98 0.93 28.10 29.10 1.42 1.45
 Body weight (BW) kg 50 389.32 390.66 22.00 41.60 728.00 741.00 30.64 29.89
 Body condition score (BCS) point 27 2.94 2.96 2.10 2.20 3.40 3.40 0.25 0.25
 Milk yield kg/d 51 31.72 32.47 20.20 18.00 45.90 44.40 4.77 4.76
 4% FCM yield kg/d 32 28.92 28.88 20.30 18.40 42.60 43.70 4.27 4.27
Milk composition
 Lactose concentration g/kg 40 47.47 47.49 40.50 43.20 52.10 51.90 1.55 1.58
 Fat concentration g/kg 46 35.94 33.20 7.90 3.17 48.00 48.80 3.98 4.22
 Protein concentration g/kg 49 31.14 30.49 28.50 27.50 37.00 35.90 2.00 1.95
 Dry matter (DM) kg/kg 42 0.60 0.61 0.23 0.13 0.76 0.83 0.05 0.05
 Organic matter (OM) kg/kg 52 0.62 0.63 0.12 0.19 0.77 0.79 0.05 0.05
 Crude protein (CP) kg/kg 52 0.49 0.55 0.02 0.15 0.98 0.97 0.04 0.04
 Neutral detergent fiber (NDF) kg/kg 30 0.49 0.49 0.08 0.09 0.55 0.54 0.03 0.03
 Acid detergent fiber (ADF) kg/kg 18 0.49 0.49 0.33 0.30 0.66 0.66 0.04 0.04
Ruminal fermentation
 Total volatile fatty acid (VFA) mmol/L 33 99.44 101.51 68.30 67.84 174.00 163.00 10.92 9.37
 Acetate1) 49 59.85 59.62 44.30 38.50 70.03 70.60 3.39 3.39
 Propionate 49 24.61 24.51 2.65 2.61 60.37 60.50 4.67 4.67
 Butyrate 47 11.11 11.72 1.21 1.11 15.10 18.70 2.12 2.06
 Iso-butyrate 31 1.72 1.62 0.24 0.25 12.80 13.50 0.32 0.32
 Iso-valerate 34 1.68 1.54 0.40 0.35 3.39 2.93 0.30 0.30
 Valerate 34 1.81 2.41 0.78 0.80 3.65 9.73 0.43 0.43

SD, standard deviation.

1) Individual VFAs are percent (%) of total VFA.

Table 3
Effects of feed extrusion on dairy performance and milk composition
Variables NC Estimate Lower bound Upper bound Std. error p-value τ2 Q Het. p-value I2
Dairy performance
 DMI 84 −0.124 −0.250 0.03 0.065 0.056 0.072 108.067 0.034 23.196
 BW 50 0.110 −0.016 0.236 0.064 0.087 0.000 46.602 0.571 0.000
 BCS 27 0.040 −0.141 0.221 0.092 0.664 0.000 18.724 0.848 0.000
 Milk yield 51 0.559 0.213 0.904 0.176 0.020 1.227 326.015 <0.001 84.663
 4% FCM yield 32 −0.014 −0.172 0.144 0.080 0.862 0.000 30.629 0.485 0.000
Milk composition
 Lactose concentration 40 0.403 0.023 0.784 0.194 0.038 1.067 184.792 <0.001 78.354
 Fat concentration 46 −0.629 −0.923 −0.336 0.150 <0.001 0.670 155.776 <0.001 70.470
 Protein concentration 49 −0.361 −0.627 −0.094 0.136 0.080 0.524 143.962 <0.001 66.658

DMI, dry matter intake; BW, body weight; BCS, body condition score; FCM, fat corrected milk.

Table 4
Effects of feed extrusion on digestibility and ruminal fermentation
Variables NC Estimate Lower bound Upper bound Std. error p-value τ2 Q Het. p-value I2
 DM 42 0.252 0.017 0.487 0.120 0.036 0.240 75.183 0.001 45.466
 OM 52 0.081 −0.134 0.296 0.110 0.461 0.249 92.553 <0.001 44.896
 CP 52 0.604 0.254 0.953 0.178 0.001 0.843 159.292 <0.001 67.983
 NDF 31 −0.085 −0.460 0.290 0.191 0.657 0.631 86.402 <0.001 65.278
 ADF 18 −0.014 −0.231 0.202 0.111 0.897 0.000 13.923 0.673 0.000
Ruminal fermentation
 Total VFA 33 0.240 −0.205 0.685 0.227 0.291 1.110 117.214 <0.001 72.700
 Acetate 49 0.022 −0.233 0.277 0.130 0.866 0.455 118.925 <0.001 59.638
 Propionate 49 −0.122 −0.303 0.058 0.092 0.185 0.093 63.097 0.071 23.926
 Butyrate 47 0.318 0.066 0.570 0.129 0.014 0.400 105.141 <0.001 56.249
 Iso-butyrate 31 −0.438 −0.844 −0.033 0.207 0.034 0.856 98.266 <0.001 69.471
 Iso-valerate 34 −0.572 −0.883 −0.261 0.159 <0.001 0.405 67.831 <0.001 51.350
 Valerate 34 0.680 0.210 1.150 0.240 0.005 1.422 143.544 <0.001 77.010

DM, dry matter; OM, organic matter; CP, crude protein; NDF, neutral detergent fiber; ADF, acid detergent fiber; VFA, volatile fatty acid.


1. Drackley JK. Calf nutrition from birth to breeding. Vet Clin North Am Food Anim Pract 2008; 24:55–86. https://doi.org/10.1016/j.cvfa.2008.01.001
crossref pmid
2. Palic D, Siebrits FK, Coetzee SE. Determining the optimum temperature for dry extrusion of full-fat soyabeans. S Afr J Anim Sci 2009; 39:Suppl 169–72.

3. Firkins JL, Eastridge ML, St-Pierre NR, Noftsger SM. Effects of grain variability and processing on starch utilization by lactating dairy cattle. J Anim Sci 2001; 79:E218–38. https://doi.org/10.2527/jas2001.79E-SupplE218x
4. Rowe JB, Choct M, Pethick DW. Processing cereal grains for animal feeding. Aust J Agric Res 1999; 50:721–36. https://doi.org/10.1071/AR98163
5. Samadi , Yu P. Dry and moist heating-induced changes in protein molecular structure, protein subfraction, and nutrient profiles in soybeans. J Dairy Sci 2011; 94:6092–102. https://doi.org/10.3168/jds.2011-4619
crossref pmid
6. Mendowski S, Chapoutot P, Chesneau G, et al. Effects of replacing soybean meal with raw or extruded blends containing faba bean or lupin seeds on nitrogen metabolism and performance of dairy cows. J Dairy Sci 2019; 102:5130–47. https://doi.org/10.3168/jds.2018-15416
crossref pmid
7. Livingstone KM, Humphries DJ, Kirton P, et al. Effects of forage type and extruded linseed supplementation on methane production and milk fatty acid composition of lactating dairy cows. J Dairy Sci 2015; 98:4000–11. https://doi.org/10.3168/jds.2014-8987
crossref pmid
8. Martin C, Rouel J, Jouany JP, Doreau M, Chilliard Y. Methane output and diet digestibility in response to feeding dairy cows crude linseed, extruded linseed, or linseed oil. J Anim Sci 2008; 86:2642–50. https://doi.org/10.2527/jas.2007-0774
crossref pmid
9. Sánchez-Meca J, Marín-Martínez F. Meta analysis. Peterson P, Baker E, McGaw B, editorsInternational encyclopedia of education. Elsevier; 2010. 274–82. https://doi.org/10.1016/B978-0-08-044894-7.01345-2
10. Rosenthal R. The file drawer problem and tolerance for null results. Psychol Bull. 1979. 86:638–41. https://psycnet.apa.org/doi/10.1037/0033-2909.86.3.638
11. Ruppar T. Meta-analysis: How to quantify and explain heterogeneity? Eur J Cardiovasc Nurs 2020; 19:646–52. https://doi.org/10.1177/1474515120944014
crossref pmid
12. Giallongo F, Oh J, Frederick T, et al. Extruded soybean meal increased feed intake and milk production in dairy cows. J Dairy Sci 2015; 98:6471–85. https://doi.org/10.3168/jds.2015-9786
crossref pmid
13. Hurtaud C, Faucon F, Couvreur S, Peyraud JL. Linear relationship between increasing amounts of extruded linseed in dairy cow diet and milk fatty acid composition and butter properties. J Dairy Sci 2010; 93:1429–43. https://doi.org/10.3168/jds.2009-2839
crossref pmid
14. Kozerski ND, Ítavo LCV, dos Santos GT, et al. Extruded urea-corn product can partially replace true protein sources in the diet for lactating Jersey cows. Anim Feed Sci Technol 2021; 282:115219 https://doi.org/10.1016/j.anifeedsci.2021.115129
15. Oliveira AS, Valadares RFD, de Campos Valadares Filho S, et al. Intake, apparent digestibility, milk composition and production of lactating cows fed four non protein nitrogen compounds levels. R Bras Zootec 2001; 30:1358–66. https://doi.org/10.1590/S1516-35982001000500032
16. de Oliveira MMNF, Torres CAA, Filho SDCV, Santos ADF, Properi CP. Urea for postpartum dairy cows: productive and reproductive performance. R Bras Zootec 2004; 33:2266–73. https://doi.org/10.1590/S1516-35982004000900012
17. Aquino AA, Botaro BG, Ikeda FDS, Rodrigues PHM, Martins MF, Santos MV. Effect of increasing dietary urea levels on milk yield and composition of lactating cows. R Bras Zootec 2007; 36:881–7. https://doi.org/10.1590/S1516-35982007000400018
18. Khan GQ, Prestløkken E, Lund P, Hellwing ALF, Larsen M. Effects of the density of extruded pellets on starch digestion kinetics, rumen fermentation, fiber digestibility and enteric methane production in dairy cows. J Anim Physiol Anim Nutr (Berl) 2023; 107:981–94. https://doi.org/10.1111/jpn.13787
crossref pmid
19. Sjaastad ØV, Sand O, Hove K. Physiology of domestic animals. 3rd edOtta, Norway: Scandinavian Veterinary Press; 2016.

20. Shabi Z, Bruckental I, Zamwell S, Tagari H, Arieli A. Effects of extrusion of grain and feeding frequency on rumen fermentation, nutrient digestibility, and milk yield and composition in dairy cows. J Dairy Sci 1999; 82:1252–60. https://doi.org/10.3168/jds.S0022-0302(99)75348-8
crossref pmid
21. Nocek JE, Braund DG. Effect of feeding frequency on diurnal dry matter and water consumption, liquid dilution rate, and milk yield in first lactation. J Dairy Sci 1985; 68:2238–47. https://doi.org/10.3168/jds.S0022-0302(85)81096-1
22. Yang CMJ, Varga GA. Effect of three concentrate feeding frequencies on rumen protozoa, rumen digesta kinetics, and milk yield in dairy cows. J Dairy Sci 1989; 72:950–7. https://doi.org/10.3168/jds.S0022-0302(89)79188-8
crossref pmid
23. Chouinard PY, Lévesque J, Girard V, Brisson GJ. Dietary soybeans extruded at different temperatures: milk composition and in situ fatty acid reactions. J Dairy Sci 1997; 80:2913–24. https://doi.org/10.3168/jds.S0022-0302(97)76257-X
crossref pmid
24. Block E, Muller LD, Griel LC, Garwood DL. Brown midrib-3 corn silage and heat extruded soybeans for early lactating dairy cows. J Dairy Sci 1981; 64:1813–25. https://doi.org/10.3168/jds.S0022-0302(81)82770-1
25. Xue B, Yan T, Ferris CF, Mayne CS. Milk production and energy efficiency of Holstein and Jersey-Holstein crossbred dairy cows offered diets containing grass silage. J Dairy Sci 2011; 94:1455–64. https://doi.org/10.3168/jds.2010-3663
crossref pmid
26. Fox PF, Uniacke-Lowe T, McSweeney PLH, O’Mahony JA. Dairy chemistry and biochemistry. 2nd edCham, Switzerland: Springer; 2015. https://doi.org/10.1007/978-3-319-14892-2

27. Berenti AM, Yari M, Khalaji S, Hedayati M, Akbarian A, Yu P. Effect of extrusion of soybean meal on feed spectroscopic molecular structures and on performance, blood metabolites and nutrient digestibility of Holstein dairy calves. Anim Biosci 2021; 34:855–66. https://doi.org/10.5713/ajas.19.0899
crossref pmid pmc
28. Gonthier C, Mustafa AF, Berthiaume R, Petit HV, Martineau R, Ouellet DR. Effects of feeding micronized and extruded flaxseed on ruminal fermentation and nutrient utilization by dairy cows. J Dairy Sci 2004; 87:1854–63. https://doi.org/10.3168/jds.S0022-0302(04)73343-3
crossref pmid
29. Kim MH, Yun CH, Lee CH, Ha JK. The effects of fermented soybean meal on immunophysiological and stress-related parameters in Holstein calves after weaning. J Dairy Sci 2012; 95:5203–12. https://doi.org/10.3168/jds.2012-5317
crossref pmid
30. Allan GL, Booth MA. Effects of extrusion processing on digestibility of peas, lupins, canola meal and soybean meal in silver perch Bidyanus bidyanus (Mitchell) diets. Aquac Res 2004; 35:981–91. https://doi.org/10.1111/j.1365-2109.2004.01114.x
31. Ruiz-Ruiz J, Martínez-Ayala A, Drago S, González R, Betancur-Ancona D, Chel-Guerrero L. Extrusion of a hard-to-cook bean (Phaseolus vulgaris L.) and quality protein maize (Zea mays L.) flour blend. LWT-Food Sci Technol 2008; 41:1799–807. https://doi.org/10.1016/j.lwt.2008.01.005
32. Ansia I, Drackley JK. Graduate student literature review: the past and future of soy protein in calf nutrition. J Dairy Sci 2020; 103:7625–38. https://doi.org/10.3168/jds.2020-18280
crossref pmid
33. Benchaar C, Bayourthe C, Moncoulon R, Vernay M. Ruminal digestion and intestinal absorption of extruded lupin seeds in lactating cows. Reprod Nutr Dev 1991; 31:655–65. https://doi.org/10.1051/rnd:19910605
crossref pmid
34. Benchaar C, Vernay M, Bayourthe C, Moncoulon R. Incidence of bean (Vicia faba) extrusion on starch and nitrogen intestinal flows in lactating cows. Reprod Nutr Dev 1992; 32:265–75. https://doi.org/10.1051/rnd:19920306
crossref pmid
35. Claassen RM, Christensen DA, Mutsvangwa T. Effects of extruding wheat dried distillers grains with solubles with peas or canola meal on ruminal fermentation, microbial protein synthesis, nutrient digestion, and milk production in dairy cows. J Dairy Sci 2016; 99:7143–58. https://doi.org/10.3168/jds.2015-10808
crossref pmid
36. Kristensen NB, Huntington GB, Harmon DL. Splanchnic carbohydrate and energy metabolism in growing ruminants. Burrin DG, Mersmann HJ, editorsBiology of growing animals. NY, USA: Elsevier; 2005. 3:p. 405–32.

37. Sakata T, Tamate H. Rumen epithelial cell proliferation accelerated by rapid increase in intraruminal butyrate. J Dairy Sci 1978; 61:1109–13. https://doi.org/10.3168/jds.S0022-0302(78)83694-7
crossref pmid
38. Dobson A, Sellers AF, Thorlacius SO. Limitation of diffusion by blood flow through bovine ruminal epithelium. Am J Physiol 1971; 220:1337–43. https://doi.org/10.1152/ajplegacy.1971.220.5.1337
crossref pmid
39. Schlau N, Guan LL, Oba M. The relationship between rumen acidosis resistance and expression of genes involved in regulation of intracellular pH and butyrate metabolism of ruminal epithelial cells in steers. J Dairy Sci 2012; 95:5866–75. https://doi.org/10.3168/jds.2011-5167
crossref pmid
40. Storm AC, Kristensen NB, Hanigan MD. A model of ruminal volatile fatty acid absorption kinetics and rumen epithelial blood flow in lactating Holstein cows. J Dairy Sci 2012; 95:2919–34. https://doi.org/10.3168/jds.2011-4239
crossref pmid
41. Akraim F, Nicot MC, Weill P, Enjalbert F. Effects of preconditioning and extrusion of linseed on the ruminal biohydrogenation of fatty acids. 1. In vivo studies. Anim Res 2006; 55:83–91. https://doi.org/10.1051/animres:2006006
42. Alvarado GC, Anrique GR, Navarrete QS. Effect of including extruded, rolled or ground corn in dairy cow diets based on direct cut grass silage. Chilean J Agric Res 2009; 69:356–65. https://doi.org/10.4067/S0718-58392009000300008
43. Annexstad RJ, Stern MD, Otterby DE, Linn JG, Hansen WP. Extruded soybeans and corn gluten meal as supplemental protein sources for lactating dairy cattle. J Dairy Sci 1987; 70:814–22. https://doi.org/10.3168/jds.S0022-0302(87)80078-4
44. Bailoni L, Bortolozzo A, Mantovani R, Simonetto A, Schiavon S, Bittante G. Feeding dairy cows with full fat extruded or toasted soybean seeds as replacement of soybean meal and effects on milk yield, fatty acid profile and CLA content. Ital J Anim Sci 2004; 3:243–58. https://doi.org/10.4081/ijas.2004.243
45. Barchiesi C, Williams P, Velásquez A. Lupin and pea extrusion decreases the ruminal degradability and improves the true ileal digestibility of crude protein. Cienc Investig Agrar 2018; 45:231–9.
46. Benchaar C, Vernay M, Bayourthe C, Moncoulon R. Effects of extrusion of whole horse beans on protein digestion and amino acid absorption in dairy cows. J Dairy Sci 1994; 77:1360–71. https://doi.org/10.3168/jds.S0022-0302(94)77075-2
crossref pmid
47. Bernard JK, Calhoun MC. Response of lactating dairy cows to mechanically processed whole cottonseed. J Dairy Sci 1997; 80:2062–8. https://doi.org/10.3168/jds.S0022-0302(97)76151-4
crossref pmid
48. Broderick GA, Kerkman TM, Sullivan HM, Dowd MK, Funk PA. Effect of replacing soybean meal protein with protein from upland cottonseed, Pima cottonseed, or extruded Pima cottonseed on production of lactating dairy cows. J Dairy Sci 2013; 96:2374–86. https://doi.org/10.3168/jds.2012-5723
crossref pmid
49. Chen KJ, Jan DF, Chiou PWS, Yang DW. Effects of dietary heat extruded soybean meal and protected fat supplement on the production, blood and ruminal characteristics of Holstein cows. Asian-Australas J Anim Sci 2002; 15:821–7. https://doi.org/10.5713/ajas.2002.821
50. Chen P, Ji P, Li SL. Effects of feeding extruded soybean, ground canola seed and whole cottonseed on ruminal fermentation, performance and milk fatty acid profile in early lactation dairy cows. Asian-Australas J Anim Sci 2008; 21:204–13. https://doi.org/10.5713/ajas.2008.70079
51. Chilliard Y, Martin C, Rouel J, Doreau M. Milk fatty acids in dairy cows fed whole crude linseed, extruded linseed, or linseed oil, and their relationship with methane output. J Dairy Sci 2009; 92:5199–211. https://doi.org/10.3168/jds.2009-2375
crossref pmid
52. Corato A, Segato S, Andrighetto I. Effects of extruded corn on milk yield and composition and blood parameters in lactating dairy cows. Ital J Anim Sci 2005; 4:166–8. https://doi.org/10.4081/ijas.2005.3s.166
53. Daniels LB, Winningham RM, Hornsby QR. Expansion-extrusion processed sorghum grain and soybeans in diets of dairy calves. J Dairy Sci 1973; 56:932–4. https://doi.org/10.3168/jds.S0022-0302(73)85280-4
54. Doreau M, Aurousseau E, Martin C. Effects of linseed lipids fed as rolled seeds, extruded seeds or oil on organic matter and crude protein digestion in cows. Anim Feed Sci Technol 2009; 150:187–96. https://doi.org/10.1016/j.anifeedsci.2008.09.004
55. dos Santos WBR, dos Santos GT, Neves CA, et al. Rumen fermentation and nutrient flow to the omasum in Holstein cows fed extruded canola seeds treated with or without lignosulfonate. R Bras Zootec 2012; 41:1747–55. https://doi.org/10.1590/S1516-35982012000700026
56. Ferlay A, Legay F, Bauchart D, Poncet C, Doreau M. Effect of a supply of raw or extruded rapeseeds on digestion in dairy cows. J Anim Sci 1992; 70:915–23. https://doi.org/10.2527/1992.703915x
crossref pmid
57. Ferlay A, Martin B, Lerch S, Gobert M, Pradel P, Chilliard Y. Effects of supplementation of maize silage diets with extruded linseed, vitamin E and plant extracts rich in polyphenols, and morning v. evening milking on milk fatty acid profiles in Holstein and Montbéliarde cows. Animal 2010; 4:627–40. https://doi.org/10.1017/s1751731109991224
crossref pmid
58. Focant M, van Hoecke A, Vanbelle M. The effect of two heat treatments (steam flaking and extrusion) on the digestion of Pisum sativum in the stomachs of heifers. Anim Feed Sci Technol 1990; 28:303–13. https://doi.org/10.1016/0377-8401(90)90161-Z
59. Gonthier C, Mustafa AF, Ouellet DR, Chouinard PY, Berthiaume R, Petit HV. Feeding micronized and extruded flaxseed to dairy cows: effects on blood parameters and milk fatty acid composition. J Dairy Sci 2005; 88:748–56. https://doi.org/10.3168/jds.s0022-0302(05)72738-7
crossref pmid
60. Guillaume B, Otterby DE, Stern MD, Linn JG, Johnson DG. Raw or extruded soybeans and rumen-protected methionine and lysine in alfalfa-based diets for dairy cows. J Dairy Sci 1991; 74:1912–22. https://doi.org/10.3168/jds.S0022-0302(91)78357-4
61. Harper MT, Oh J, Melgar A, et al. Production effects of feeding extruded soybean meal to early-lactation dairy cows. J Dairy Sci 2019; 102:8999–9016. https://doi.org/10.3168/jds.2019-16551
crossref pmid
62. Illg DJ, Stern MD, Mansfield HR, Crooker BA. Effects of extruded soybeans and forage source on fermentation by rumen microorganisms in continuous culture. J Dairy Sci 1994; 77:1589–97. https://doi.org/10.3168/jds.S0022-0302(94)77101-0
crossref pmid
63. Kim YK, Schingoethe DJ, Casper DP, Ludens FC. Supplemental dietary fat from extruded soybeans and calcium soaps of fatty acids for lactating dairy cows. J Dairy Sci 1993; 76:197–204. https://doi.org/10.3168/jds.S0022-0302(93)77338-5
crossref pmid
64. Kudlinskienė I, Gružauskas R, Daukšienė A, et al. Effect of extrusion on the chemical composition of the faba beans and its influence on lactation performance of dairy cows. Zemdirbyste 2020; 107:87–94. https://doi.org/10.13080/z-a.2020.107.012
65. Larsen M, Lund P, Storm AC, Weisbjerg MR. Effect of conventional and extrusion pelleting on postprandial patterns of ruminal and duodenal starch appearance in dairy cows. Anim Feed Sci Technol 2019; 253:113–24. https://doi.org/10.1016/j.anifeedsci.2019.04.012
66. Masoero F, Moschini M, Fusconi G, Piva G. Raw, extruded and expanded pea (Pisum sativum) in dairy cows diets. Ital J Anim Sci 2006; 5:237–47. https://doi.org/10.4081/ijas.2006.237
67. Mendowski S, Chapoutot P, Chesneau G, et al. Effects of pretreatment with reducing sugars or an enzymatic cocktail before extrusion of fava bean on nitrogen metabolism and performance of dairy cows. J Dairy Sci 2020; 103:396–409. https://doi.org/10.3168/jds.2019-17286
crossref pmid
68. Moats J, Mutsvangwa T, Refat B, Christensen DA. Evaluation of whole flaxseed and the use of tannin-containing fava beans as an alternative to peas in a co-extruded flaxseed product on ruminal fermentation, selected milk fatty acids, and production in dairy cows. Prof Anim Sci 2018; 34:435–46. https://doi.org/10.15232/pas.2018-01726
69. Mustafa AF, Gonthier C, Ouellet DR. Effects of extrusion of flaxseed on ruminal and postruminal nutrient digestibilities. Arch Anim Nutr 2003; 57:455–63. https://doi.org/10.1080/0003942032000161036
70. Orias F, Aldrich CG, Elizalde JC, Bauer LL, Merchen NR. The effects of dry extrusion temperature of whole soybeans on digestion of protein and amino acids by steers. J Anim Sci 2002; 80:2493–501. https://doi.org/10.1093/ansci/80.9.2493
crossref pmid
71. Paula EM, Broderick GA, Danes MAC, Lobos NE, Zanton GI, Faciola AP. Effects of replacing soybean meal with canola meal or treated canola meal on ruminal digestion, omasal nutrient flow, and performance in lactating dairy cows. J Dairy Sci 2018; 101:328–39. https://doi.org/10.3168/jds.2017-13392
crossref pmid
72. Petit HV, Rioux R, Ouellet DR. Milk production and intake of lactating cows fed raw or extruded peas. J Dairy Sci 1997; 80:3377–85. https://doi.org/10.3168/jds.S0022-0302(97)76313-6
crossref pmid
73. Ramaswamy N, Baer RJ, Schingoethe DJ, Hippen AR, Kasperson KM, Whitlock LA. Composition and flavor of milk and butter from cows fed fish oil, extruded soybeans, or their combination. J Dairy Sci 2001; 84:2144–51. https://doi.org/10.3168/jds.S0022-0302(01)74659-0
crossref pmid
74. Rezamand P, Andrew SM, Hoagland TA. The feeding value of extruded corn grain in a corn silage-based ration for high-producing Holstein cows and heifers during mid lactation. J Dairy Sci 2007; 90:3475–81. https://doi.org/10.3168/jds.2006-438
crossref pmid
75. Sadr-Arhami I, Ghorbani GR, Kargar S, Sadeghi-Sefidmazgi A, Ghaffari MH, Caroprese M. Feeding processed soybean to mid-lactation Holstein cows: ingestive behaviour and rumen fermentation characteristics. Ital J Anim Sci 2019; 18:696–703. https://doi.org/10.1080/1828051X.2018.1564378
76. Schingoethe DJ, Casper DP, Yang C, Illg DJ, Sommerfeldt JL, Mueller CR. Lactational response to soybean meal, heated soybean meal, and extruded soybeans with ruminally protected methionine. J Dairy Sci 1988; 71:173–80. https://doi.org/10.3168/jds.S0022-0302(88)79539-9
crossref pmid
77. Scott TA, Combs DK, Grummer RR. Effects of roasting, extrusion, and particle size on the feeding value of soybeans for dairy cows. J Dairy Sci 1991; 74:2555–62. https://doi.org/10.3168/jds.S0022-0302(91)78433-6
78. Solanas E, Castrillo C, Balcells J, Guada JA. In situ ruminal degradability and intestinal digestion of raw and extruded legume seeds and soya bean meal protein. J Anim Physiol Anim Nutr (Berl) 2005; 89:166–71. https://doi.org/10.1111/j.1439-0396.2005.00555.x
crossref pmid
79. Soltan MA. Rumen fermentation characteristics and lactation performance in dairy cows fed different rumen protected soybean meal products. Pak J Nutr 2009; 8:695–703. https://doi.org/10.3923/pjn.2009.695.703
80. van Dijk HJ, O’Dell GD, Perry PR, Grimes LW. Extruded versus raw ground soybeans for dairy cows in early lactation. J Dairy Sci 1983; 66:2521–5. https://doi.org/10.3168/jds.S0022-0302(83)82121-3
81. Whitlock LA, Schingoethe DJ, AbuGhazaleh AA, Hippen AR, Kalscheur KF. Milk production and composition from cows fed small amounts of fish oil with extruded soybeans. J Dairy Sci 2006; 89:3972–80. https://doi.org/10.3168/jds.S0022-0302(06)72440-7
crossref pmid
82. Ye JA, Wang C, Wang HF, et al. Milk production and fatty acid profile of dairy cows supplemented with flaxseed oil, soybean oil, or extruded soybeans. Acta Agric Scand A Anim Sci 2009; 59:121–9. https://doi.org/10.1080/09064700903082252
83. ZeidAli-Nejad A, Ghorbani GR, Kargar S, Sadeghi-Sefidmazgi A, Pezeshki A, Ghaffari MH. Nutrient intake, rumen fermentation and growth performance of dairy calves fed extruded full-fat soybean as a replacement for soybean meal. Animal 2018; 12:733–40. https://doi.org/10.1017/s1751731117002154
crossref pmid
84. Zhang YQ, He DC, Meng QX. Effect of a mixture of steam-flaked corn and soybeans on health, growth, and selected blood metabolism of Holstein calves. J Dairy Sci 2010; 93:2271–9. https://doi.org/10.3168/jds.2009-2522
crossref pmid
85. Schauff DJ, Clark JH, Drackley JK. Effects of feeding lactating dairy cows diets containing extruded soybeans and calcium salts of long-chain fatty acids. J Dairy Sci 1992; 75:3003–19. https://doi.org/10.3168/jds.S0022-0302(92)78064-3
crossref pmid

Editorial Office
Asian-Australasian Association of Animal Production Societies(AAAP)
Room 708 Sammo Sporex, 23, Sillim-ro 59-gil, Gwanak-gu, Seoul 08776, Korea   
TEL : +82-2-888-6558    FAX : +82-2-888-6559   
E-mail : editor@animbiosci.org               

Copyright © 2024 by Asian-Australasian Association of Animal Production Societies.

Developed in M2PI

Close layer
prev next