END OF FEEDING TRIAL REPORT FOR THE ASESSEMENT OF THE FFECT OF

SWEETPOTATO VINES SILAGE ON LACTATING ANKOLE X FRESIAN CROSS

BRED DAIRY COWS

BY

1Nampijja Z.; 1Lutwama V.; 2Kyalo, G.; 2Mayanja S.; 3Grant F.; 4Kabirizi J.; 5Namagembe A.; 6Lugoloobi S.; 6Wasswa R. and 1Galla N.A

1Makerere University, Uganda; 2International Potato Centre (CIP), Uganda; 3CIP- Tanzania; 4Kyakuwa Farm, Uganda; 5National Livestock Resources Research Institute, Uganda; 6Sight

Farm, Nakyesasa, Wakiso district;

Table of Contents

List of tables....................................................................................................................................3

Summary of results..........................................................................................................................4

Background......................................................................................................................................5

Objectives.....................................................................................................................................5

Materials and methods.....................................................................................................................6

Description of experimental site..................................................................................................6

Experimental animals and experimental design...........................................................................6

Experimental diets........................................................................................................................8

Sweetpotato vine silage production..........................................................................................8

Chloris gayana (rhodes grass) hay...........................................................................................9

Homemade dairy pellets...........................................................................................................9

Chemical analysis......................................................................................................................10

Statistical analyses.....................................................................................................................10

Results............................................................................................................................................11

Chemical composition of the feedstuffs.....................................................................................11

Dry matter intake and live weight changes................................................................................12

Milk yield and composition.......................................................................................................13

Cost of supplementation.............................................................................................................14

Discussion......................................................................................................................................15

Conclusion and recommendation..................................................................................................16

Acknowledgements........................................................................................................................16

References......................................................................................................................................17

2

LIST OF TABLES

Table 1: Allocation and changeover of experimental diets.............................................................7

Table 2: Chemical composition (as offered) of the mineral blocks used in supplementing the

experimental cows*.........................................................................................................................8

Table 3: Simple formula for making homemade dairy pellets........................................................9

Table 4: Chemical composition (g/kg DM) of the feeds used in feeding the lactating dairy cows

.......................................................................................................................................................11

Table 5: Dry matter intake and live weight changes of cows fed the experimental diets.............12

Table 6: Milk yield and composition from cows fed the experimental diets................................13

Table 7: Economics of supplementing dairy cows with varying levels of SPVS.........................14

3

Summary of results

Seasonal feed shortages coupled with the high prices of feed supplements are key constraints to

investment and profitability of smallholder dairy production in Uganda. This study was

conducted to evaluate the effect of sweetpotato vine silage (SPVS) supplementation on lactating

Ankole x Fresian crossbred dairy cattle. Four primiparous cows in their early lactation were

randomly allotted to a basal diet of Chloris gayana hay supplemented with dairy pellets and four

graded levels of SPVS (0, 10, 20 and 30% of the daily ration) in a 4X4 Latin square design. The

animals were given a one-week adaptation period followed by a two weeks’ data collection

period for each diet. Dry matter intake (DMI), live weight changes, milk yield and composition

were determined. Dry matter intake improved with addition of SPVS with intake being highest in

cows that were fed the highest SPVS level (P < 0.05). In vitro organic matter digestibility

increased with SPVS supplementation level. Animals fed diets with 0, 10 and 20% SPVS levels

of supplementation lost weight, however, there were no significant differences (P ≥ 0.05) in body

weight changes with increasing supplementation level. Milk yield increased with SPVS

supplementation although there were no significant differences between the different SPVS

supplementation levels. Milk fat differed (P ≤ 0.05) with supplementation, but there was no

consistent trend observed. Considering profit margins, supplementing dairy cows with SPVS at a

level of 10% of their daily feed intake was most profitable and yielded Uganda shillings 1,290 on

daily basis. In conclusion, SPVS supplementation improved digestibility, DMI and milk yield

but supplementation beyond 10% of the daily feed intake was not cost effective.

4

Background

The seasonal variability in quantity and quality of milk produced by smallholder dairy farmers is

affected by many factors among which is feed quality and quantity. The dry seasons experienced

in Uganda greatly impact on both the quality and quantity of the feed resource base for dairy

animals resulting into reduced productivity and profitability. However, Uganda is among the top

countries in Africa in production of sweetpotatoes (SP) whose residues can be used as animal

feed. Sweetpotato vine silage contributes 40% of the feed resource during the dry season. The SP

vines are bulky, highly perishable and a lot is wasted despite their potential contribution to the

feed resource base for smallholder zero grazing systems.

Sweet potato vine (SPV) silage technology as a technique for prolonging the shelf life of SPV

was tested in Masaka and Kamuli districts under CIP-led RTB ENDURE project as one of the

interventions to reduce feed cost and feed shortage and improve pig production in smallholder

pig production systems in Uganda. The results showed improved performance of pigs fed sweet

potato silage supplemented with a homemade concentrate (Mutetikka et al., 2016). Reports from

dairy farmers in Wakiso, Mukono and Masaka districts showed that dairy farmers had resorted to

supplementation of their lactating dairy cows with SPV silage to buffer variation in quality and

quantity of feed during the prolonged drought. The used SPV silage to improve the diet of their

animals reported to have observed increase in milk yield (Daaki, 2018; personal

communication). However, no research has been conducted in Uganda to assess performance of

lactating dairy cows fed Sweetpotato Vine Silage (SPVS). There was therefore a need to conduct

on-farm trials to verify farmers’ observations.

Objectives

To determine the effect of supplementing crossbred dairy cows with SPV silage on milk

yield, milk composition and live weight gains.

To disseminate information on production and utilization of SPSV technology to dairy

cattle farmers.

5

Materials and methods

Description of experimental site

The study was conducted at Site Farm located in Nakyesasa village, Busukuma sub-county,

Wakiso District. The District lies in the Central region and about which is about 18 Km from

Kampala city along the Kampala- Busiika road. Selection of the farm was based on; willingness

of the farm owner to participate in the study; willingness of the farm owner to allow other

farmers to visit the experimental site for purposes of monitoring and evaluation of the trial and to

learn from participating farmer; having sweetpotato as one of the major crops grown on the farm;

having at least four early lactating mono-porous crossbred dairy cows.

Experimental animals and experimental design

Four lactating crossbreed Friesian dairy cows with exotic blood level of about 83% (first calving)

in their early lactation (3 months after calving) with an average milk yield of 9.21 ± 1.68 liters

per day and average body weight of 422.92 ± 26.15 kg were identified for use in the feeding

trial. Four diets were offered to the animals in a 4 x 4 Latin Square change over design with four

periods each lasting two weeks. Animals were given an adaptation period of one week before the

start of data collection for every period. Apart from the adaptation week before the

commencement of the experiment, were all animals fed on six (6kg) of SPVS, the rest of the

adaptation periods animals were fed on the treatments diets that they received during the data

collection periods. The basal diet consisted of Rhodes grass hay which was offered to ad libitum

to the experimental animals. Each of the animals was supplemented with four (4kg) of dairy

pellets in addition to the SPVS treatment diets so as to provide at least above 12 % CP required

for moderate levels of production (ARC, 1980). The SPVS was offered at 0, 10, 20 and 30% of

the total daily intake. The percentage inclusions translated into 0, 6kg, 12kg, 18kg of SPVS

representing diet I, II, III, IV respectively. The SPVS was offered to the animals following the

order indicated in Table 1 below. The SPVS was offered routinely at 10: 00am while Dairy

pellets were offered in equal proportions just before milking both at 5:00 am and 4:00 pm, and

were consumed during the milking period. Before adding each day's ration, the leftover feed was

removed and weighed. The daily feed intake was determined by subtracting the refused feed of a

6

given day from the total feed offered that day. Feeds were sampled and taken to the laboratory

for chemical analyses.

Table 1: Allocation and changeover of experimental diets

Diets (Based on SPVS supplementation)

Animal Name Period 1 Period 2 Period 3 Period 4

Juliet

Natendo

Nabukenya

Namwanje

II

I

IV

III

III

IV

I

II

IV

III

II

I

I

II

III

IV

The animals were enclosed in individual kraals and were treated against internal and external

parasites before commencement of the experiment and throughout the experimental period. The

animals had free access to clean drinking water and mineral block licks (chemical composition

presented in Table 2). Milking was done twice a day at 5:00 am and at 4:00 pm and the total

daily yields were recorded. Milk samples were collected during the second week of data

collection on each diet, mixed thoroughly and taken to the laboratory to be analysed for protein,

milk fat, total solids and ash. The live body weight changes (kg) of the animals in each treatment

were determined by taking initial weights after the adaptation period for the animals in each

treatment, and subtracting it from the final weights at the end of each data collection period.

7

Table 2: Chemical composition (as offered) of the mineral blocks used in supplementing the

experimental cows*

Ingredient Level (%)

Phosphorus 0.20

Calcium 0.14

Magnesium 0.50

Iron 0.15

Cobalt 0.005

Copper 0.03

Iodine 0.015

Manganese 0.02

Zinc 0.03

Selenium 0.001

Sodium 38

*As guaranteed by the manufacturers Supplied by Coopers Uganda Limited, Kampala (Uganda).

Experimental diets

Sweetpotato Vine silage production

Sweetpotato vines were purchased from both Owino market in Kampala district and farmers’

fields in Seguku and Nakyesasa villages, Wakiso district. After harvesting, the vines were wilted

for 2 to 3 hours depending on the source. Vines from the market already had lower moisture

content compared to those from the field. The wilted material was chopped using a motorized

forage chopper to length of about 2 cm for ease of compaction so as to increase the quality and

storability of silage. It is easier to displace air during ensiling when small pieces are cut. The

chopped sweetpotato vines were weighed and spread on a tarpaulin to be mixed thoroughly with

maize bran. Maize bran was added to chopped vines in a ratio of 1: 10. Maize bran was used

instead of molasses because the bran reduces the quantity of effluent from the sweetpotato silage

(Kabirizi et al., 2017). The mixture was put in polythene tube silos in small quantities and

compressed until the bag was full. The bags were firmly tied with a sisal string excluding the air

8

in order to encourage anaerobic fermentation. The polythene tubes silos were stored in a well-

ventilated store free from rodents until they were ready for use.

Chloris gayana (Rhodes grass) hay

Rhodes grass hay was purchased from the National Livestock Resources Research Institute

(NaLIRRI) in Wakiso district. At the institute the grass was cut when about 10% of the crop had

flowered. The cut material was left in the field to dry for 2 days. The dry grass was raked into

heaps and later baled using a simple bottomless wooden baling box.

Homemade dairy pellets

The pellets were produced using maize bran, cotton seed cake, mineral premix, Calliandra leaf

hay meal and molasses in proportions shown in Table 3. The different ingredients were

thoroughly mixed and after mixing, the mash was delivered to the pellet mill feeder for pelleting.

The extruded pellets had a moisture content of 16-17%, these were then dried to a moisture

content below 12%.

Table 3: Simple formula for making homemade dairy pellets

Ingredient Quantity (kg)

Maize bran 52

Cotton seed cake 18

Mineral premix 2

Calliandra calothyrsus leaf hay 9

Molasses (liters) 18

9

Chemical analysis

Feed samples were oven dried at 600C for 48 hours in a forced draught oven and then ground

through a 1mm sieve for chemical analyses. Dry matter, ash and nitrogen (Kjeldahl-N) in feeds

and refusals as well as milk composition (CP, butterfat and total solids) were determined

according to procedures outlined by AOAC (1990). Acid detergent fibre, NDF and acid insoluble

ash were determined according to procedures outlined by Van Soest and Robertson (1985).

Statistical analyses

The effects of the levels of SPVS on feed intake, body weight changes and milk yield and

composition were tested using Analysis of Variance (ANOVAs) of the General Linear Models

Procedure (GLM) in SAS (1990) for a balanced 4x4 Latin square design using the model below:

Xijk = + i + j + k + ijk; i , j and k = 1 ......a

Where: Xijk = the kth observation on the response variable under the ith treatment

= Over all mean

i = Treatment effect (i = 1…4)

j = Period effect (j = 1…4)

k = Animal effect (k = 1…4)

ijk = Random error effect

Differences among treatment means were compared using Tukey’s test of SAS (1990).

10

RESULTS

Chemical composition of the feedstuffs

Chemical composition of the different diet ingredients is presented in Table 4. Dry matter, NDF

and ADF levels of the ingredients were highest in the Rhodes grass hay (RGH). Sweetpotato

vine silage had a noticeably higher CP level than dairy pellets, and both had high ME levels.

Table 4: Chemical composition (g/kg DM) of the feeds used in feeding the lactating dairy

cows

RGH SPVS Dairy pellets

Proximate Component

Dry matter 830 266 680

Crude Protein 75 194 148

Neutral detergent fiber 780 333 157

Acid detergent fiber 441 186 59

Acid detergent lignin 137 59 40

Ash 104 85 74

ME (MJ/kg DM) 198 772 795

RGH = Rhodes grass hay, SPVS = sweetpotato vine silage

11

Dry matter intake and live weight changes

Intake of CP, NDF, ME and digestibility of the diets were observed to increase as the level of

SPVS supplementation increased (Table 5). There was a general DMI increase with increasing

levels of SPVS supplementation. Dry matter intake was recorded to be lowest at D0 and highest

at D30. There was a general body weight loss from D0 to D30, though a gain in body weight at

diet D30 was recorded. In vitro organic matter digestibility increased with level of

supplementation.

Table 5: Dry matter intake and live weight changes of cows fed the experimental diets

Diets

Parameter D0 D10 D20 D30 SEM

Dry matter intake (kg/day)

Rhodes grass hay 4.1 4.2 4.3 4.4 0.24

Sweetpotato vine silage 0.0 1.6 3.2 4.8 0.00

Dairy Pellets 2.7 2.7 2.7 2.7 0.00

Total DMI 6.8 d 8.5c 10.2b 11.9a 0.24

Total CP intake 0.7 1.0 1.3 1.7 0.02

Total ME intake 44.8 63.4 82.1 101.1 0.72

Total NDF intake 3.7 4.2 4.8 5.5 0.19

Total ADF intake 2.0 2.3 2.6 3.0 0.11

IVOMD (g/kg) 442.1 510.4 549.6 566.0 13.9

Total DMI (%BW) 1.6 2.0 2.4 2.8

Average final weights (Kg) 

Live weight changes

414.8

-5.59c

415.4

-1.19a

418.9

-0.29a

432

1.52b

4.87

0.39

Diets D0, D10, D20 and D30 had sweetpotato vine silage at 0, 10, 20 and 30% levels, respectively. a,b,c,d Means

within a row with different superscripts differ significantly (P < 0.05). SEM = Standard error of the mean.

Calculated based on digestibility of individual ingredients.

12

Milk yield and composition

Daily milk yield increased with supplementation although there was no significant difference (P

≥ 0.05) with increasing levels of SPVS supplementation. Milk yield was lowest at D0 and

highest at D10 (Table 6).

There were significant differences (P < 0.05) in butter fat and total solids in milk from cows

across all the diets however, FCM increased and no significant difference (P ≥ 0.05) was

recorded between the levels of SPVS supplementation (Table 4).

Table 6: Milk yield and composition from cows fed the experimental diets

 Parameter   Diets      

Milk yield (kg)

D0 D10 D20 D30 SEM

Daily yield 8.3 b  10.0a 9.8 a 9.9 a 0.26

Fat corrected milk 9.21b 10.21a 10.76a 10.82a 0.28

Milk composition (%)

Total solids 12.9 12.8 12.9 12.8 0.10

Butter fat 4.7a 4.1b 4.7a 4.6ab 0.14

Solids-not-fat 8.2b 8.6a 8.2b 8.2b 0.06

Diets D0, D10, D20 and D30 had sweetpotato vine silage at 0, 10, 20 and 30% levels, respectively. a,b Means within

a row with different superscripts differ significantly (P < 0.05). SEM = Standard error of the mean.

13

Cost of supplementation

The cost of feeding increased with levels of supplementation which resulted into negative profits

at higher SPVS supplementation (Table 7). On the other hand, additional income due to

supplementation increased at D10 and thereafter decreased with incremental SPVS

supplementation levels. The most profitable level of supplementation was achieved when diet

D10 was fed.

Table 7: Economics of supplementing dairy cows with varying levels of SPVS

Diets

Cost of

supplementation

Increase in milk

yield Additional income Profit

D0 0 0 0 0

D10 1410 1.8 2700 1290

D20 2820 1.5 2250 -570

D30 4230 1.6 2400 -1830

Cost of producing SPVS is Ushs 235/kg and price of milk is Ushs 1500/liter

14

Discussion The recorded crude protein content (194g/kg) in this study was higher than what was earlier reported (Khalid et al. 2013, Negesse et al. 2016, Lutwama et al. 2016). These variations are attributable to difference in varieties, foliage to stem ratio and part of the vines that are being ensiled (Aregheore, 2004; Zereu et al. 2014). The dry matter level of 226g/kg in SPVS is within the range reported by (Murugan et al. 2012). The high CP and dry matter levels reported in this study therefore makes SPVS a good feed resource and supplement for diets with limiting protein (Nambi-Kasozi et al. 2016).

Dry matter intake as a percentage of body weight was lowest in cows fed diet D0 possibly due to either rumen fill or limitation of intake as a result of low palatability of the Rhodes grass hay. Dry matter intake and digestibility of the diets increased with supplementation level due to the increase in organic matter digestibility contributed by the SPVS. High In vitro organic matter digestibility of SPVS subsequently improves intake of the basal diet to enhance rumination and raise the rumen pH. These observations are in agreement with Megersa et al. 2012; Ali et al. (2019)

The observed loss of average body weight over the feeding period despite the increasing ME values as the supplementation levels were increased is in agreement with what was earlier reported by Gross et al. (2011). These observations are due to the DMI, milk yield and body weight changes which usually occur in the first phase (4 months) of lactation in primiparous cattle. The weight loss could probably be attributed to a potential negative energy balance or taken as a normal phenomenon in premiparous lactating cows that are experiencing increasing levels of milk yield (Poncheki et al., 2015).

Milk yield was higher and similar in cows fed the different SPVS supplementation levels. This result is due to increased DMI intake hence more nutrient ingestion and nitrogen utilization with increasing SPVS supplementation (Ali et al. 2019). Butter fat content improved with SPVS supplementation though there were no consistent results within levels of supplementation. This can be as a result of increasing levels of fibrous material in the diets known to balance the acetate to propionate levels in the rumen liquor as acetate is a major milk fat precursor ( Kawas and Mahgoub, 2005).

15

Conclusion and recommendation

From this study it can be concluded that SPVS can be used to improve the quality of feed, feed

intake, productivity and quality of milk and profitability as well as buffering the feed shortages

among smallholder dairy farming communities. Sweet potato vine silage has a high crude protein

content which makes it a suitable supplement for lactating dairy animals being fed protein

deficient diets. Supplementing lactating dairy animals with up to 10% SPVS increases body

weight gain and milk yield resulting into a profitable dairy enterprise. Supplementing dairy

animals beyond 10% of the daily feed intake would increase milk yield and body weight but

would not be cost effective.

Farmers should produce SPVS and supplement the basal diet at 10% in order to enjoy the

following benefits;

• An improvement on the nutritional content of the animal diet,

• An increase in milk yield which translates into increased profits,

• Sustaining milk production through the dry spells, periods of feed scarcity and,

• Maintaining the body condition scores of the animals

Acknowledgements

The study was supported by the International Potato Center (CIP), conducted by Bavubuka

Twekembe youths and Kyakuwa Farm and hosted by Sight farm.

16

References

Ali, A. I. M., Wassie, S. E., Korir, D., Merbold, L., Goopy, J. P., Butterbach-bahl, K., … Schlecht, E. (2019). Utilization and Reduced Enteric Methane Emissions.

AOAC (Association of Official Analytical Chemists). (1990). In: Official Methods of

Analysis15th Ed. AOAC Inc., Arlington, Virginia 22201 USA.

ARC. (1990). The Agricultural Research Council (ARC). The Agricultural Research Council (ARC). Retrieved from http://www.arc.agric.za/

Aregheore, E. M. (2004). Nutritive value of sweet potato (Ipomea batatas (L) Lam) forage as goat feed: Voluntary intake, growth and digestibility of mixed rations of sweet potato and batiki grass (Ischaemum aristatum var. indicum). Small Ruminant Research, 51(3), 235–241. https://doi.org/10.1016/S0921-4488(03)00198-6

Ashiono lG.B. A, 2J.0. Ouda, 3T.E. Akuja, lJ.K. Kitilit, lR. G. I. and ’s. G. (2006). Effect of Potato Vines and Sorghum Silage on Cattle Milk Productivity. Asian Journal of Plant Sciences 5 (1): 81-84,2006. https://doi.org/10.3923/ajps.2006.81.84

Balikowa, D. (2011). A Review of Uganda ’ s Dairy Industry. A Review of Uganda’s Dairy Industry, 3202(March), 89.

Close, W., & Menke, K. H. (1986). Selected Topics in Animal Nutrition Universitat. Hohenheim, 170(85).

Dione, M. M., Pezo, D., Kyalo, G., Mayega, L., Nadiope, G., & Lukuyu, B. (2015). Perception and practices of farmers on the utilization of sweetpotato, and other root tubers, and banana for pig feeding in smallholder crop-livestock systems in Uganda. Livestock Research for Rural Development, 27(11).

Etela, I., Oji, U. I., Kalio, G. A., & Tona, G. O. (2008). Studies on sweet potato forage and dried brewers’ grains as supplements to green panic for Bunaji cows. Tropical Grasslands, 42(4), 245–251.

Gross, J., van Dorland, H. A., Bruckmaier, R. M., & Schwarz, F. J. (2011). Performance and metabolic profile of dairy cows during a lactational and deliberately induced negative energy balance with subsequent realimentation. Journal of Dairy Science, 94(4), 1820–1830. https://doi.org/10.3168/jds.2010-3707

Kabirizi, J. M., Lule, P., Kyalo, G., Mayanja, S., Ojakol, J. F., Mutetikka, D., … Lukuyu, B. (2017). Sweetpotato Silage Manual for Smallholder Farmers Expanding Utilization of Roots, Tubers and Bananas and Reducing Their Postharvest Losses Sweetpotato Silage Making Manual for Smallholder Farmers 1, (February).

17

Kabunga, N. (2015). Improved Dairy Cows in Uganda: Pathways to Poverty Alleviation and Improved Child Nutrition. European Journal of Nutrition & Food Safety, 5(5), 886–887. https://doi.org/10.9734/ejnfs/2015/21146

Katongole, C. B., Bareeba, F. B., Sabiiti, E. N., & Ledin, I. (2008). Nutritional characterization of some tropical urban market crop wastes. Animal Feed Science and Technology, 142(3–4), 275–291. https://doi.org/10.1016/j.anifeedsci.2007.09.002

Katongole, Constantine Bakyusa, Sabiiti, E., Bareeba, F., & Ledin, I. (2011). Utilization of market crop wastes as animal feed in urban and peri-urban livestock production in Uganda. Journal of Sustainable Agriculture, 35(3), 329–342. https://doi.org/10.1080/10440046.2011.554318

Kawas Lu, C. D., R., J., & Mahgoub, O. G. (2005). Fibre digestion and utilization in goats. Small Ruminant Research, 60(1-2 SPEC. ISS.), 45–52. https://doi.org/10.1016/j.smallrumres.2005.06.035

Khalid, A., Elamin, K., Amin, A., Eldar, A., Mohamed, M., Hassan, H., & Mohammed, M. (2013). Effect of Feeding Sweet Potato (Ipomoea batatas) Vines Silage on Performance and Milk Production of Nubian Goats. Journal of Veterinary Advances, 3(5), 153. https://doi.org/10.5455/jva.0130517045658

Lukuyu, B. A., Kitalyi, A., Franzel, S., Duncan, A., & Baltenweck, I. (2009). Constraints and options to enhancing production of high quality feeds in dairy production in Kenya, Uganda and Rwanda. ICRAF Working Paper no. 95. Nairobi, Kenya: World Agroforestry Centre., 34. https://doi.org/10.5716/WP16449.PDF

Lutakome, P., Kabi, F., Tibayungwa, F., Laswai, G. H., Kimambo, A., & Ebong, C. (2017). Rumen liquor from slaughtered cattle as inoculum for feed evaluation. Animal Nutrition, 3(3), 300–308. https://doi.org/10.1016/j.aninu.2017.06.010

Lutwama. V, Gumisiriza. M, Dr. Kabirizi. J, N. Z. and K. M. (2016). Evaluation of Nutritional Quality of Silage From Sweet Potato Vines , Napier Grass and Their Mixtures As. International Journal of Agriculture and Environmental Research, 02(06), 1696–1708.

Kiggundu M., Kabi F., Mette V., Nalubwama S., C. O. (2014). Management and use of dairy cattle feed resources on smallholder certified organic pineapple farms in Central Uganda. Journal of Agriculture and Environment for International Development, 108(2), 207–225. https://doi.org/10.12895/jaeid.20142.253

Megersa, T., Urge, M., & Nurfeta, A. (2012). Effects of feeding sweet potato (Ipomoea batatas) vines as a supplement on feed intake, growth performance, digestibility and carcass characteristics of Sidama goats fed a basal diet of natural grass hay. Tropical Animal Health and Production, 45(1), 593–601. https://doi.org/10.1007/s11250-012-0264-4

Mugerwa, Swidiq., Kabirizi, J. M., Nanyenya, William., Matovu, M., & Komutunga, Everlyne., Mubiru, Drake N., Agona, Ambrose., Zziwa, E. (2013). Simulation of Methane Emissions from Stall Fed DairyAnimals under Different Dietary Strategies in Uganda. Frontiers in

18

Science, 3(1), 1–5. https://doi.org/10.5923/j.fs.20130301.01

Murugan, S., Paramasivam, S. K., & Nedunchezhiyan, M. (2012). Sweet Potato as animal feed and fodder. Fruit, Vegetable and Cereal Science and Biotechnology, 6(Special Issue 1), 106 0 114.

Nambi-Kasozi, J., Sabiiti, E. N., Bareeba, F. B., Sporndly, E., & Kabi, F. (2016). Effects of inclusion levels of banana (Musa spp.) peelings on feed degradability and rumen environment of cattle fed basal elephant grass. Tropical Animal Health and Production, 48(4), 693–698. https://doi.org/10.1007/s11250-016-0999-4

Negesse, T., Gebremichael, G., & Beyan, M. (2016). Supplementary effect of Sweet Potato (Ipomoea batatas) Silage on Growth Performance and Carcass Traits of Local Lambs Grazing Natural Pasture in Tembaro District, Southern Ethiopia. International Journal of Environment, Agriculture and Biotechnology, 1(3), 457–465. https://doi.org/10.22161/ijaers/3.10.23

Okalebo, J. R. (1993). Laboratory methods of soil and plant analysis: a working manual. Unesco/Rosta.

Phesatcha, K., & Wanapat, M. (2012). Performance of lactating dairy cows fed a diet based on treated rice straw and supplemented with pelleted sweet potato vines. Tropical Animal Health and Production, 45(1), 533–538. https://doi.org/10.1007/s11250-012-0255-5

Poncheki, J. K., Canha, M. L. S., Viechnieski, S. L., & de Almeida, R. (2015). Analysis of daily body weight of dairy cows in early lactation and associations with productive and reproductive performance. Revista Brasileira de Zootecnia, 44(5), 187–192. https://doi.org/10.1590/S1806-92902015000500004

SAS. (2001). Statistical Analysis System, User’s guide, version 8.2. SAS Institute Inc., Cary, NC, USA.

Semwogerere, F., Kigozi, A. & Kabi, F. (2016). Effect of supplementing steers with graded levels of concentrate on rumen environment and degradation kinetics of Chloris gayana hay, 14(14), 237–245.

The Republic of Uganda. (2012). Uganda Vision 2040, 1–120.

Tilley, J. M. A., & Terry, R. A. (1963). a Two‐Stage Technique for the in Vitro Digestion of Forage Crops. Grass and Forage Science, 18(2), 104–111. https://doi.org/10.1111/j.1365-2494.1963.tb00335.x

Van Soest, P. J., Robertson, J. B., & Lewis, B. A. (1991). Methods for Dietary Fiber, Neutral Detergent Fiber, and Nonstarch Polysaccharides in Relation to Animal Nutrition. Journal of Dairy Science, 74(10), 3583–3597. https://doi.org/10.3168/jds.S0022-0302(91)78551-2

Yacout, M., Khayyal, A. A., AM, S., & Khalel, M. (2016). Introduce Sweet Potato Vines as Good Roughage for Small Ruminants. EC Veterinary Science, 2(4), 184–204.

19

Zereu, G., Negesse, T., & Nurfeta, A. (2014). Chemical composition and in vitro dry matter digestibility of vines and roots of four sweet potato (Ipomoea batatas) varieties grown in Southern Ethiopia. Tropical and Subtropical Agroecosystems, 17(3), 547–555.

20