Niger oil cake
Niger oil cake is a good protein supplement in ruminant diets. It is mainly used in sheep and goat diets for growth or fattening, and to a lesser extent in dairy and beef cattle diets. In most cases, niger oil cake is used to supplement low quality forages (protein content < 7% DM). This supplementation has a positive effect on the digestibility of cell wall constituents which creates a positive effect in the rumen and allows better fibre degradability (Butterworth et al., 1986). It also has a positive effect on diet and forage DM digestibility, provided dietary energy is sufficient as observed with dairy cows, goats, and sheep studies (Kebede et al., 2009; Nuwanyakpa et al., 1987). All results presented and discussed below come from studies done in Ethiopia.
Dairy cows
In Ethiopia, it was reported that some farmers prefer to feed niger oil cake rather than linseed cake for milk production because cows fed with the latter become fat, and milk production decreases (Gebremedhin et al., 2009). When Friesian x Zebu dairy cows (404-430 kg, 107 days in milk) were fed for 3 months with ad libitum low quality hay plus molasses-urea block supplemented with 1 or 2 kg/d of niger oil cake, average milk yield was not different between the two levels of niger oil cake (3.8-3.9 L/d) and neither was milk composition (Little et al., 1987). When indigenous dairy cows (232 kg, lactation stage not indicated) were fed on pasture for 45 days and supplemented with niger oil cake or commercial concentrate, at the same rate of 0.25 kg/kg milk, average daily milk yield (1.6 to 1.5 kg) and milk composition were identical. Even though the commercial concentrate contained 50% less protein, milk yield was not different, probably because the concentrate contained 75% maize grain and 25% niger oil cake (Kebede et al., 2009). This agrees with the observation mentioned above, where niger oil cake supplemented at 1 kg/d gave a response of 0.260 kg/L milk, and 2 kg/d without more energy did not result in higher milk yield (Little et al., 1987). Recent observations of dairy cow diets in the Tigray region suggested that niger cake enhanced milk yield when included at 10% of the diet in combination with 9-20% atella as a supplement to a wheat bran/barley straw-based diet (Alemayehu Tadesse et al., 2016).
Beef cattle
When Arsi oxen (Bos indicus) were fed on low quality teff straw and supplemented with 2 kg/d niger oil cake, 1 kg/d niger oil cake plus 1 kg/d molasses or 1.5 kg/d maize grain plus 73 g/d urea, daily weight gain increased with the protein intake. The daily weight gain was 517 g/d with 2 kg niger oil cake and 322 g/d with 1 kg/d niger oil cake plus molasses. However, the diets were not isonitrogenous and the differences could be due to this effect (Mengistu, 2003). When young Borana x Jersey bulls or heifers were fed ad libitum with haricot bean straw alone or supplemented with either niger oil cake (1.09 kg DM/d) or linseed cake (1.20 kg DM/d), daily weight gain increased with both supplements from 122 to 525 and 695 g/d in bulls, and from 167 to 430 and 582 g/d in heifers, respectively. The straw DM intake increased with the two supplements from 2.78 to 3.01 and 3.10 kg/d. Although weight gains were higher with linseed cake, niger oil cake was more cost-effective. However, these results must be viewed with caution because the diets were probably not isonitrogenous, as niger oil cake is often lower in protein than linseed cake, and niger oil cake was also supplemented at a lower amount (1.09 vs. 1.20 g/d) (Tolla et al., 2001). However, in both experiments, the daily weight gain was almost the same for males supplemented with 2 kg/d niger oil cake: 517 and 525 g/d.
Sheep
Because niger oil cake is a good source of protein for diets based on poor quality forages, a good source of energy (e.g. maize grain, wheat bran, possibly spineless cactus) must be provided to enhance the positive effect of niger oil cake on growth and digestibility. Adding an energy supplement with niger oil cake (50 to 117 g/d) increased the daily weight gain of lambs (16-17 kg) up to 53-54 g/d (Kabaija et al., 1989; Osuji et al., 1993; Gebremariam et al., 2006; Lamaro et al., 2016). When niger oil cake was included at 25 or 67% in a concentrate, fed at increasing levels (150 to 400 g/d) as a supplement to low or medium quality hay offered to males (17-18 kg), DM digestibility and daily weight gain increased (Hagos et al., 2009; Asmare et al., 2010). Niger oil cake replaced cottonseed cake in a concentrate offered to growing lambs fed with straw ad libitum, and resulted in a daily weight gain of 23 g/d (Alem et al., 2011). When niger oil cake replaced cottonseed cake or groundnut cake as a protein supplement in an isonitrogenous diet based on straw and spineless cactus offered to fattening males, the daily weight gain was lower than with the two other supplements, although DM digestibility was highest with niger oil cake (Degu et al., 2009). Niger oil cake gave the same daily weight gain (73.4 g/d) as wheat bran (70.1 g/d) offered at the same level (300 g/d) in a diet based on low quality hay (Bishaw et al., 2008). Rice bran could not replace niger oil cake at the same level because of its low protein content (one third of niger oil cake) (Nega et al., 2009).
Table 1. Effect of niger oil cake supplementation in sheep
| Animal type and breed |
Experiment |
Level of niger cake (on as fed basis unless specified) |
Main results |
Reference |
Male
(17 kg)
local |
Wheat straw (2.5% CP) supplemented with WB (150 g/d) and various amounts of NC and LL leaves |
110 to 200 g/d |
Straw DMI slightly increased when LL replaced NC from 23 to 66% on DM basis; DWG was higher only with 66% LL (59 vs. 53 g/d). Total DMD was not different at any % replacement, but crude protein digestibility was higher at 66% (75 vs. 69%). |
Tesfay et al., 2013 |
Male
(17 kg)
Adilo |
Low quality hay (2.8% CP) supplemented with 200 g/d of a mixed concentrate including various proportions of NC in place of pigeon pea leaves |
0, 15, 28 or 43 g DM/d |
Different niger cake proportions into the concentrate had no effect on DMI, DMD or DWG. |
Nurfeta et al., 2013 |
Rams
(18 kg)
Afar fat tail |
Low quality hay (5.8% CP) supplemented with increasing levels (150, 250, 350 g/d) of concentrate including 25% NC |
38, 62.5 or 87.5 g/d |
Increasing levels of concentrates decreased hay DMI at the highest level (519 vs. 384 g/d) and DMD of the diet at all levels (67-68% vs. 50%). Supplements at all levels increased DWG from -2 g/d to 43-67 g/d. |
Hagos et al., 2009 |
Male
(17 kg)
Farta |
Medium quality hay (9.2% CP) supplemented with 200 to 400 g/d of concentrate including 67% NC |
150, 225 or 300 g DM/d |
Increasing levels of concentrates decreased hay DMI and increased diet DMD. 200 g of concentrate highly increased DWG from 3 to 38 g/d up to 72 g/d with the highest level. |
Asmare et al., 2010 |
Lambs
(15 kg) Ethiopian Highland |
Straw (3.4% CP) supplemented with 300 g/d of concentrate including WB and either NC or CSC as nitrogen source |
78 g/d |
There was no difference between NC or CSC on straw DMI (332 g/d), DWG (23 g/d), diet DMD (54.5%) or feed conversion efficiency (22.4). |
Alem et al., 2011 |
Male
(21 kg)
Tigray Highland |
Medium quality hay (7.9% CP) supplemented with 172 g of spineless cactus plus CSC, NC or GNC as protein supplement |
195 g DM/d |
Hay DMI was not modified by supplementation except with NC which decreased it from 524 to 380 g/d. DMD was higher with NC and GNC supplements (64-66% vs. 57%). DWG was higher with CSC and GNC (69 and 57 g/d) than with NC (35 g/d) or without supplement (20 g/d). |
Degu et al., 2009 |
Male
(19 kg)
Farta |
Medium quality hay (7% CP) supplemented at the same level with NC or RB |
300 g/d |
Hay DMI decreased (from 610 to 402-420 g/d) with both NC and RB. Diet DMD and DWG were higher with NC (65% and 57.8 g/d) than with RB (52% and 5.6 g/d) supplement. But RB had a lower CP content (110 vs. 312 g/kg DM). |
Nega et al., 2009 |
Male
(17 kg)
Farta |
Low quality hay (3.6% CP) supplemented at the same level with NC or WB |
300 g/d |
Hay DMI decreased from 541 to 488 (WB) and 366 g/d (NC). Diet DMD tended to be higher with NC (64.9%) and WB (61.5%) than with hay alone (52.8%). NC or WB increased DWG from -9.1 g/d to 73.4 g/d (NC) or 70.1 g/d (WB). |
Bishaw et al., 2008 |
Lambs
(16 kg)
Menz |
Maize stover (3.8% CP) supplemented (isonitrogenous) with CSC, SFC or NC with (50 g/d) or without corn grain |
114 g/d |
The protein source (with or without maize grain) had no effect on maize stover DMI. Adding maize grain increased the DWG with all protein supplements (44 to 54 g/d). |
Osuji et al., 1993 |
Male
(17 kg) Hararghe Highland |
Maize stover (4.6% CP) supplemented with NC (60 g/d) or 150, 250 or 350 g of concentrate (2/3 WB and 1/3 NC) |
50 to 117 g/d |
DMD of the diet supplemented with NC alone was lower than with all levels of concentrate (60.8 vs. 70.5%) and DWG was much lower (-19 vs. 60 g/d). |
Lamaro et al., 2016 |
Ewes
(23 kg)
Menz |
Grazing poor quality pasture (4,4% CP) + NC alone or with molasses urea block |
100 g/d |
No effect of any supplement on body weight change and reproduction results. Stocking rate and biomass availability are not indicated. |
Kabaija et al., 1989 |
Male
(17 kg) Highland |
Tef straw (7.6% CP) and spineless cactus pads in various proportions supplemented with NC |
61 g/d |
DWG and DMD without cactus were low (23.6 g/d and 51%) but higher when cactus replaced half the straw (52.9 g/d and 64%). |
Gebremariam et al., 2006 |
CP: crude protein; CSC: cottonseed cake; DMD: dry matter digestibility; DMI: dry matter intake; DWG: daily weight gain; GNC: groundnut cake; LL: Leucaena leucocephala; NC: niger oil cake; SFC: sunflower cake; RB: rice bran; WB: wheat bran
Goats
When niger oil cake was included at 20% in a concentrate, offered as a supplement to young fattening goats (14 kg) for 4 months, daily weight gain was higher when the ratio of concentrate:forage was the highest (80:20). There were no effects on carcass quality or composition (Sebsibe et al., 2007). When niger oil cake was compared (in isonitrogenous diets) with cottonseed cake and linseed cake as a supplement to medium quality hay (10% protein) fed to Sidawa growing males (16 kg), there was no difference in hay DM intake (52-59 g DM/kg W0.75) or diet DM digestibility (58 to 67%). However, daily weight gain was lower with niger oil cake: 28 g/d compared to 60-62 g/d with the two other cakes (Alemu et al., 2010).
Forage
Information about the use of the niger plant as forage is limited. Early experiments reported that niger plants could be cut at the flowering stage and fed as green fodder to sheep. They were reported to be unpalatable to cattle unless chopped and made into silage. An alternative use was as fencing around fields (Chavan, 1961; Melaku, 2013). Recently it has been suggested that from its chemical composition and in vitro analysis, niger could be used as a valuable forage provided it was cut no later than the shooting stage, because in vitro digestibility decreases with increasing maturity (Peiretti et al., 2015).
