Comparative feeding value of steam-flaked triticale as a replacement for steam-flaked corn in finishing diets for feedlot cattle

ABSTRACT

Forty-eight crossbred steers (296 ± 5 kg) were used in a 155-day trial to compare the feeding value of steam-flaked triticale (SFT) with steam-flaked corn (SFC). Dietary treatments were: (1) basal finishing diet (BD), (2) 40% BD plus 60% SFT, and (3) 40% BD plus 60% SFC. Substitution of BD with SFT or SFC increased gain efficiency (P < .01), tended to increase average daily gain (ADG) (P = .07) and decrease dry matter intake (P = .11). The derived net energy for maintenance (NE_m) and net energy for gain (NE_g) values of SFT averaged 2.28 and 1.59 Mcal/kg, respectively. Four steers (442 ± 28 kg) were used in a 4 × 4 Latin square experiment to determine the effects of replacement of SFC with SFT on digestion. Treatments consisted of a SFC basal diet where SFT replaced 0, 32, 64, and 96% of SFC. Increasing level of SFT decreased total tract digestion of organic matter (OM) (linear component, P = .03), acid detergent fiber (ADF) (linear component, P < .01), and digestible energy (DE) (linear component, P < .01). The replacement DE value for SFT averaged 3.88 Mcal/kg, corresponding to NE_m and NE_g values of 2.18 and 1.50 Mcal/kg, respectively. It is concluded that the replacement net energy (NE) value of SFT is 92–96% that of SFC.

KEYWORDS:

• Triticale
• corn
• cattle
• performance
• digestion

1. Introduction

Triticale is an inter-generic hybrid between wheat and rye. Its crude protein content, although quite variable (8–24%, Farell et al. 1983; Royo et al. 1993; Goonewardene et al. 1994; Wojtkowiak et al. 2014), is generally greater than that of either wheat or rye. Agronomic performance of improved triticale hybrids is comparable to wheat (Royo & Pares 1996). Hill and Utley (1989) observed a 5% decrease in dietary TDN when triticale replaced 50% of cracked corn in a finishing diet for feedlot cattle. However, in a short-term 63-day feeding trial, average daily gain (ADG) and gain efficiency of feedlot heifers were not affected by the replacement. In contrast, Yazdani and Hajilari (2009) in an 83-day feeding trial observed greater ADG and gain efficiency of feedlot steers fed a ground corn-based diet than for those fed a ground triticale-based finishing diet. Prado et al. (2000) in an 84-day feeding period observed that replacement of ground sorghum with 0%, 33%, 66%, or 100% triticale did not affect ADG or gain efficiency of feedlot bulls. Zobell et al. (1990) observed that partial or complete replacement of ground barley with ground triticale did not affect ADG or gain efficiency of feedlot heifers in a trial of 120-day. To our knowledge, there is no published research evaluating the comparative feeding value of steam-flaked triticale (SFT) in finishing diets for feedlot cattle. The objective of the present study was to evaluate the comparative digestible energy (DE) and net energy (NE) value of SFT versus steam-flaked corn (SFC) in growing finishing diets for feedlot cattle.

2. Materials and methods

2.1. Trial 1

Forty-eight medium-frame crossbred (approximately 25% Brahman blood with the remainder represented by Hereford, Angus, Shorthorn and Charolais breeds in various proportions) steers with an average weight of 296 ± 5 kg were used in a 155-day trial to evaluate the comparative feeding value of SFT as a partial replacement for SFC. Composition of the experimental diets is shown in Table 1. Dietary treatments were: (1) basal finishing diet, (2) 40% basal diet plus 60% SFT, and (3) 40% basal diet plus 60% SFC. This treatment design allows for the estimation of the NE value of SFT both directly, using the substitution and indirectly, using the replacement techniques. SFC was prepared by steaming corn at atmospheric pressure (steam chest set at 102°C) before rolling to a mean density of 0.27 kg/L. The retention time of corn in the steam chamber was maintained at approximately 34 min. The SFC was then allowed to air-dry before use in the diet formulation. SFT was prepared in a similar manner, except that retention time of triticale in the steam chamber was approximately 18 min and flake density was 0.26 kg/L. Steers were blocked by weight and allotted to six pens (eight steers/pen, two pens/treatment), equipped with automatic waterers and fence-line feed bunks. Upon initiation of the study and then subsequently at day 56, steers were implanted with Synovex-S (Zoetis Inc., New York, NY). Hot carcass weights (CWs) were obtained from all steers at time of slaughter. Estimates of ADG and energy gain were based on shrunk body weight (SBW), assuming that SBW is 96% of full weight (NRC 1996). Final body weight was adjusted for CW by dividing it by 0.64 (decimal fraction of average dressing percentage, where dressing percentage = 100 × CW/SBW). The estimation of dietary NE was performed by means of the quadratic formula: , where x = NE_m (net energy for maintenance), a = −0.41 EM, b = 0.877 EM + 0.41 DMI + EG, and c = −0.877 DMI, where EM (energy required for maintenance, Mcal/day) = 0.077SBW^0.75, DMI = observed average dry matter intake (kg/day), and . Dietary NE_g (net energy for gain) was derived from NE_m by the equation: NE_g = 0.877 NE_m – 0.41 (Zinn et al. 2008a).

Table 1. Composition of experimental diets fed to steers (Trial 1).

Item	Treatments
	100% Basal	40% Basal	40% Basal
		60% SFT	60% SFC
Ingredients (%, DM basis)
Alfalfa hay	15.00	6.00	6.00
Sudan grass hay	10.00	4.00	4.00
SFC	60.88	24.35	83.40
SFT	0	59.05	0
Cottonseed meal	6.55	2.63	1.63
Cane molasses	6.00	2.40	2.40
Limestone	0.80	0.80	0.80
Urea	0	0	1.00
Dicalcium phosphate	0.27	0.27	0.27
Trace mineral salt^a	0.50	0.50	0.50
Lasalocid (mg/kg)	30	30	30
Nutrient composition, DM basis^b
NE (Mcal/kg)
Maintenance	2.00	2.02	2.19
Gain	1.35	1.37	1.52
DE (Mcal/kg)	3.57	3.61	3.81
Crude protein (%)	12.8	12.3	13.1
Ether extract (%)	3.6	2.7	3.91
Calcium (%)	0.72	0.51	0.50
Magnesium (%)	0.20	0.19	0.15
Phosphorus (%)	0.36	0.42	0.35
Potassium (%)	1.11	0.69	0.63

^aTrace mineral salt contained: CoSO₄, 0.068%; CuSO₄, 1.04%; FeSO₄, 3.57%; ZnO, 0.75%; MnSO₄, 1.07%; KI, 0.052%; and NaCl, 93.4%.

^bBased on tabular values for individual feed ingredients (NRC 1984) with exception of supplemental fat which was assigned NE_m and NE_g values of 6.03 and 4.79 Mcal/kg, respectively (Zinn 1988).

Data were analysed as a completely random design using individual pens as the experimental unit (Statistix 9, Analytical Software, Tallahasse, FL). Treatment effects were tested using F test statistic for the following orthogonal contrasts: basal vs. basal plus test grain, and SFT vs. SFC.

2.2. Trial 2

Four crossbred steers (442 ± 28 kg) were used in a 4 × 4 Latin square experiment to determine the effect of SFC replacement with SFT on characteristics of digestion. Compositions of experimental diets are shown in Table 2. Treatments consisted of a SFC basal diet where SFT replaced 0%, 32%, 64%, and 96% of SFC. Chromic oxide (0.40%, dry matter (DM) basis) was included in diets as a digesta marker. Steers were maintained in individual pens (3.9 m²) with access to water at libitum. DMI was restricted to 5.9 kg/day (1.3% of SBW). Daily feed allowance was offered in equal portions at 0800 and 2000 daily. The four experimental periods consisted of a 10-day diet adjustment period followed by a 4-day collection period. During the collection period faecal samples were taken from all steers, twice daily as follows: day 1, 1050 and 1450; day 2, 0900 and 1500; day 3, 0730 and 1330, and day 4, 0600 and 1200, respectively. Individual samples consisted of approximately 200 g (wet basis) of faecal material. Samples from each steer and within each collection period were composited for analysis. Feed and faecal samples were prepared for analysis by oven-drying at 70°C and then grinding in a laboratory mill. Samples were then oven dried at 105°C until no further weight loss occurred and stored in tightly sealed glass jars. Samples were subjected to the following analysis: DM (oven-drying at 105°C until no further weight loss), ash, Kjeldahl N (AOAC 2000), acid detergent fiber (ADF) (Goering & Van Soest 1970), starch (Zinn 1990), chromic oxide (Hill & Anderson 1958), and gross energy (GE) (adiabatic bomb calorimetry). Faecal excretion of DM was calculated based on marker ratio using chromic oxide. Treatment effects on digestion were analysed as a 4 × 4 Latin square design. Treatment effects were tested using orthogonal polynomial for linear and quadratic components (Statistix 9, Analytical Software, Tallahasse, FL).

Table 2. Composition of experimental diets fed to steers (Trial 2).

Item	SFT (%)
	0	23	46	69
Ingredients (%, DM basis)
Alfalfa hay	10.50	10.50	10.50	10.50
Sudan grass hay	7.00	7.00	7.00	7.00
SFC	71.75	48.75	25.75	2.75
SFT	0	23.00	46.00	69.00
Cottonseed meal	4.10	4.10	4.10	4.10
Cane molasses	4.20	4.20	4.20	4.20
Limestone	0.80	0.80	0.80	0.80
Dicalcium phosphate	0.27	0.27	0.27	0.27
Trace mineral salt^a	0.50	0.50	0.50	0.50
Urea	0.48	0.48	0.48	0.48
Chromic oxide	0.40	0.40	0.40	0.40
Lasalocid (mg/kg)	30	30	30	30
Nutrient composition, DM basis^b
NE (Mcal/kg)
Maintenance	2.07	2.00	1.93	1.85
Gain	1.42	1.36	1.29	1.23
DE (Mcal/kg)	3.66	3.57	3.48	3.39
Crude protein (%)	12.9	13.5	14.1	14.7
Ether extract (%)	3.7	3.2	2.7	2.2
Ash (%)	6.0	6.0	6.0	6.0

^aTrace mineral salt contained: CoSO₄, 0.068%; CuSO₄, 1.04%; FeSO₄, 3.57%; ZnO, 0.75%; MnSO₄, 1.07%; KI, 0.052%; and NaCl, 93.4%.

^bBased on tabular values for individual feed ingredients (NRC 1984) with exception of supplemental fat which was assigned NE_m and NE_g values of 6.03 and 4.79 Mcal/kg, respectively (Zinn 1988).

3. Results and discussion

3.1. Trial 1

Nutrient composition and test weights of triticale and corn used in this study are shown in Table 3. Compared with tabular values (NRC 1984), triticale used in this study was lower in crude protein (12.1% vs. 17.6%), but similar in ether extract (2.1% vs. 1.7%) and ash (2.1 vs. 2.0).

Table 3. Nutrient composition of triticale and corn used in Trials 1 and 2.

Item	Triticale	Corn
Dry matter (%)	93.8	90.2
Ash (%)	2.1	1.3
ADF (%)	3.8	3.0
Ether extract (%)	2.1	3.8
Starch (%)	67.1	72.9
Crude protein (%)	12.1	9.7
Test weight (kg/L)
Whole	0.68	0.71
Steam-flaked	0.26	0.27

Treatment effects on cattle growth-performance and estimated dietary NE are shown in Table 4. The substitution of basal diet with SFT and SFC increased gain efficiency (P < .01), associated with a tendency for increased ADG (P = .07) and decreased DMI (P = .11). Gain efficiency tended to be greater (P = .07) for SFC than for SFT. Substitution of basal diet with SFT and SFC increased (P < .01) estimated dietary NE_m and NE_g. Observed dietary NE values of the basal diet and basal diet plus 60% SFC were in close agreement (98% and 101%, respectively) with expected based on diet formulation and tabular values of feed ingredients (Table 1; NRC 1984).

Table 4. Treatment effects on growth-performance of feedlot steers and NE value of the diet (Trial 1).

Item	Treatments			P-value		SEM
	100% Basal	40% Basal	40% Basal	Basal vs. SFT, SFC	SFT vs. SFC
		60% SFT	60% SFC
Days on test	155	155	155
Initial weight (kg)^a	294	293	302	.46	.18	4
Final weight (kg)^a	466	474	497	.01	.01	3
CW	298	303	317	.01	.01	2
ADG (kg)	1.11	1.17	1.26	.07	.14	0.03
DMI (kg/day)	7.74	7.16	7.42	.11	.34	0.16
ADG/DMI	0.144	0.164	0.169	<.01	.07	0.001
Diet NEm (Mcal/kg)	1.96	2.16	2.22	<.01	.20	0.02
Diet NEg (Mcal/kg)	1.31	1.49	1.54	<.01	.20	0.02
Observed/expected dietary NE
Maintenance	0.98	1.07	1.01	.04	.01	0.01
Gain	0.99	1.09	1.02	.04	.01	0.01

^aInitial and final weights were reduced 4% to adjust for digestive tract fill. Final weights were carcass adjusted (CW/0.64, average dressing percentage).

There are no previously published studies comparing SFT with SFC in finishing diets for feedlot cattle. In 63-day feeding trial, Hill and Utley (1989) observed that ADG and gain efficiency of feedlot heifers were not affected by the replacement of cracked corn with triticale. In contrast, in an 83-day finishing study, Yazdani and Hajilari (2009) observed greater ADG and gain efficiency of feedlot steers fed a ground corn-based diet than for those fed a ground triticale-based diet.

The NE values of SFT can be estimated using both the substitution and replacement techniques. In the case of the substitution technique, the NE_m and NE_g values for SFT are determined as follows: NE SFT = (NE basal plus SFT diet – 0.40 NE basal diet)/0.60, where 0.40 and 0.60 are the proportions of basal diet and SFT, respectively. Accordingly, the NE_m and NE_g values for SFT are 2.29 and 1.60, respectively. In a similar manner, the substitution NE_m and NE_g values for SFC are 2.39 and 1.69, respectively. These values correspond closely with tabular NE values (2.38 and 1.68 Mcal/kg, respectively; NRC 1984), and previous growth-performance trials evaluating the NE value of SFC (2.46 and 1.74, Mcal/kg, respectively; Zinn et al. 2011).

Using the replacement technique, the NE_m value of SFT can be determined as follows: NE_m SFT = 2.38–(NE_m basal plus SFC diet–NE_m basal plus SFT diet)/0.60, where 2.38 is the tabular NE_m value for SFC (NRC 1984) and 0.60 is the proportion of grain used in the replacement. Accordingly, the comparative NE_m value of SFT is 2.28 Mcal/kg, and the corresponding NE_g value is 1.59 Mcal/kg. Thus, both approaches (substitution and replacement techniques) corroborate well in estimates of NE values for SFT.

Observed dietary NE_m value of the basal diet plus 60% SFT was 7% greater than expected. There are no previously reported studies with which to compare the NE_m and NE_g values for SFT derived in the present study. The NRC (1996) does not provide tabular values for triticale, either dry-processed or steam-flaked. As with other small grains (wheat, oats, and barley), the NRC (1984) likewise does not provide values for SFT. Their tabular NE_m and NE_g values for triticale ‘grain’ are 2.06 and 1.40 Mcal/kg, respectively, approximately 90% of that derived in the present study.

Part of the greater observed NE values for triticale observed in the present study may be attributable to steam-flaking. For example, Zinn (1994) observed that flaking wheat increased its NE_m and NE_g values from 2.18 and 1.50, respectively, to 2.28 and 1.59 Mcal/kg, respectively. The NE values obtained for steam-flaked wheat in that study closely compare with that of SFT in the present experiment. Consistently, an increase in NE_m and NE_g for steam-flaked vs. dry-rolled has been observed in barley (Zinn 1993), corn (Zinn et al. 1998), and sorghum (Zinn et al. 2008b).

3.2. Trial 2

The influence of SFC replacement with SFT on characteristics of digestion is shown in Table 5. Across treatments, starch digestion averaged 99% and was not affected (P = .57) by replacement of SFC with SFT. However, an increasing level of SFT substitution for SFC decreased digestion of organic matter (OM) (linear component, P = .03) and ADF (linear component, P < .01), but tended to increase apparent N digestion (P = .09). Consistently SFC has shown lower total tract N digestion than SFW (Zinn 1992) and SFB (Zinn 1993). This latter effect is expected due to the increasing level of dietary N brought about by the replacement (NRC 1985).

Table 5. Treatment effects on characteristics of digestion.

Item	SFT (%)				P-value
	0	23	46	69	Linear	Quadratic	SEM
Intake (g/day)
DM^a	5826	5864	5870	5893	.04	.69	17
OM	5530	5552	5559	5571	.11	.77	15
ADF	656	663	656	647	.48	.41	10
Starch	3039	2846	2859	2795	<.01	.07	28
N	109	120	127	136	<.01	.47	1
GE (Mcal)	25.7	25.6	24.3	25.3	<.01	.73	0.1
Faecal excretion (g/day)
OM	843	919	894	986	.02	.79	30
ADF	367	394	386	433	<.01	.35	10
Starch	23.1	27.1	22.6	24.7	.97	.72	2.4
N	22.0	24.6	22.8	24.0	.47	.57	1.2
GE (Mcal)	4.53	4.85	4.70	5.16	.06	.70	0.2
Total tract digestibility (%)
OM	84.8	83.4	83.9	82.3	.03	.79	0.5
ADF	44.0	40.6	41.0	33.1	<.01	.27	1.2
Starch	99.2	99.0	99.2	99.1	.59	.57	0.1
N	79.8	79.5	82.0	82.3	.09	.80	1.1
DE (%)	82.4	81.1	81.5	79.6	.04	.71	0.7
DE (Mcal/kg)	3.63	3.55	3.51	3.42	<.01	.94	0.03

^aDry matter intake was restricted to 1.3% of BW daily.

The DE value of the 0% SFT supplemented diet (3.63 Mcal/kg) compared closely with expected (3.66 Mcal/kg) based on diet formulation and tabular values for individual feed ingredients (Table 2). As with Trial 1, the DE value of SFT can be estimated using the replacement technique: SFT, Mcal/kg = 4.19 + (DE SFT diet–DE SFC diet)/replacement level, where 4.19 is the tabular DE value for SFC (NRC 1984). Accordingly, the DE value for SFT averaged 3.88 Mcal/kg (3.84, 3.93, and 3.88 Mcal/kg, for the 23%, 46%, and 69% replacement levels, respectively). Given that the relationship between DE and NE_m (NE_m, Mcal/kg = 0.708 DE–0.568; NRC 1996), the corresponding NE_m and NE_g values SFT in this trial averaged 2.18 and 1.50 Mcal/kg, respectively, approximately 96% of that observed based on growth-performance in the Trial 1.

4. Conclusion

The feeding value of SFT corresponds to 96% the net energy value of SFC. Hence, gain efficiency will be correspondingly lower for SFT than for SFC-based diets.

Disclosure statement

No potential conflict of interest was reported by the authors.