Livestock Husbandry: Pig Feed Improvement

		Pig Feed Improvement through Enhanced Use of Sweet Potato Roots and Vines in Northern and Central Vietnam
		Contents:
		INTRODUCTION
		PART I -SELECTING AND GROWING SWEET POTATO FOR LIVESTOCK
		1	Technology for growing dual-purpose and forage-purpose sweetpotato in the Northern Midlands of Vietnam
		2	Technology for growing dual-purpose and forage-purpose sweetpotato in the Red River Delta of Vietnam
		3	Technology for growing dual-purpose and forage-purpose sweetpotato in North-Central Vietnam
		PART II - SWEETPOTATO ROOT AND VINE PROCESSING AND FEEDING TO PIGS
		1	Sweetpotato vine and root ensiling methods and use of silage as pig feed
		2	Feed crops and their processing and storage methods
		3	Composition of concentrate feed mixtures (basal feed) and the rations for pigs for various weight categories
		Technical supplement: Some principles of pig nutrition in the tropics

2 Technology for growing dual-purpose and forage-purpose sweetpotato in the Red River Delta of Vietnam

2.1 Characteristics of the Red River Delta

2.1.1 Soils

The Red River Delta was deposited by the Red River and the Thai Binh River, resulting in fertile alluvial soils. Total land area of the Red River Delta is 1,250,000 ha., of which Agricultural land occupies 721,321 ha. (57%). Of the total agricultural land, 643,021 ha is cultivated annually, leaving only 11% to fallow. Rice cultivation, as the most important crop, occupies 91% of annual crop land area.

2.1.2 Climatic conditions

The Red River Delta has a monsoon climate. The average temperature between November and April is 15-18°C, with the coldest months in January and February, when it can drop to as low as 5-9°C. There are two distinct seasons a year: dry season from November to April and rainy season from May to October. The average rainfall is 1,800-2,000 mm, mainly concentrated during the rainy season, when it usually storms and floods the delta between July and October.

2.1.3 Population and density

The small area of the Red River Delta boasts a big population of 14,800,100, with the majority (78.9 %) residing in rural areas. Due to the high population density, agricultural land per capita averages only 553 m2. The Kinh people comprise the majority of the population in the area.

2.1.4 Crops and production systems

Sweetpotato is planted in winter between two rice crops to serve a feed source for animal production in fresh and processed form. The agriculture rotation systems are as below.

- On secondary land:

Winter/Spring sweetpotato - Sesame - Autumn/Winter sweetpotato
Spring groundnut - Sesame - Autumn/Winter sweetpotato
Winter/Spring sweetpotato - Sesame - Autumn groundnut

- One rice crop with two secondary crops:

Winter/Spring sweetpotato - Main winter rice
Spring sweetpotato - Early winter rice - Potato
Spring sweetpotato - Early winter rice - Winter sweetpotato
Spring groundnut - Early winter rice - Winter sweetpotato
Winter sweetpotato - Winter rice seedling - Late winter rice

- Two rice crops with a winter crop:

Late spring rice - Early winter rice - Winter sweetpotato

2.2 Geographical location

The Red River Delta of Vietnam consists of the following provinces: Hai Phong, Hai Duong, Hung Yen, Ha Tay, Ha Noi, Nam Dinh, Ha Nam, Thai Binh and Ninh Binh. The following recommendations also apply to some neighbouring provinces that share similar topographical and soil characteristics.

2.3 Recommended sweetpotato varieties suitable for root and vine dual-purpose and their characteristics.

2.3.1 The characteristics of yield, agronomic performance, and growing period

Distinguishing characteristics	Varieties
	Hoang long	Nr.8	KL5	KL6	KB1
Root yield (ton/ha)	16-18	18-20	22-27	24-28	16-30
Vine yield (ton/ha)	17-20	18-20	20-25	21-25	18-20
Root DM yield (ton/ha)	4.59	5.65	6.25	6.35	6.46
Root starch yield (ton/ha)	3.93	4.84	5.25	5.18	5.34
Season suited to planting	Winter	Winter, spring	Winter, spring	Winter, spring	Winter, spring
Tolerance performance:
Drought tolerance	Fair	Fair	Good	Fair	Fair
Submergence tolerance	Poor	Poor	Poor	Poor	Poor
Cold tolerance	Medium	Fair	Good	Fair	Fair
Leaf insect tolerance	Fair	Fair	Fair	Fair	Fair
Weevil tolerance	Medium	Fair	Fair	Fair	Fair
Growing time (days)	100-120	100-120	100-120	100-120	100-120

2.3.2 The characteristics of utilization, vine, root and storage

Distinguishing characteristics	Varieties
	Hoang long	Nr.8	KL5	KL6	KB1
Root palatability:
For humans (boiled)	High DM	High DM	High DM	Med. DM	High DM
For pigs (cooked)	Good	Good	Good	Good	Good
Vine palatability:
For humans (boiled)	Bitter	Med. sweet	Sweet	Sweet	Med. sweet
For pigs (fresh)	Bitter (Should be cooked)	Med. sweet (Should be cooked)	Sweet	Sweet	Med. sweet
Method of storage:
Time (month)	3	3-4	3-4	3-4	3-4
Way to store	Dried	Dried	Dried	Dried	Dried
Roof morphology
Color of skin	Light red	Red-Pink	Red-Pink	Red	White
Color of root flesh	Yellow	Ivory white	Ivory white	Ivory white	Ivory
Shape of root	Slender	Slender	Slender	Slender	Slender

2.4 Sweetpotato varieties suitable for forage purpose and their characteristics

2.4.1 The characteristics of yield, agronomic performance, and growing period

Distinguishing characteristics	Varieties
	Hoanglong	Nr.8	KL1	KL5	KL6
Fresh vine yield (ton/ha)	17-20	18-20	20-25	20-25	21-25
Fresh leaf yield (ton/ha)	11.75	12.50	14.25	13.50	13.25
Leaf DM yield (ton/ha)	2.30	3.25	3.80	3.90	3.01
Leaf CP yield (ton/ha)	0.34	0.49	0.54	0.58	0.48
Season suited for planting	Winter	Winter, spring	Winter, spring	Winter, spring	Winter, spring
Tolerance performance:
Drought tolerance	Fair	Fair	Fair	Fair	Fair
Submergence tolerance	Poor	Poor	Poor	Poor	Poor
Cold tolerance	Medium	Fair	Fair	Fair	Fair
Leaf insect tolerance	Fair	Fair	Fair	Fair	Fair
Weevil tolerance	Medium	Fair	Fair	Fair	Fair
Branching	Strong	Strong	Strong	Strong	Strong
Re-growing	Fair	Fair	Fair	Fast	Fair

2.4.2 The characteristics of utilization, vine, root and storage

Distinguishing characteristics	Varieties
	Hoang long	Nr.8	KL1	KL5	KL6
Vine palatability:
For humans (boiled)	Strong, a bit sweet	Med. sweet	Med. sweet	Sweet	Sweet
For pigs (fresh)	Strong, a bit sweet (Should be cooked)	Med. sweet	Med. sweet	Sweet	Sweet
Method of storage:
Time (month)	3-4	3-4	3-4	3-4	3-4
Way to store	Dried	Dried	Dried	Dried	Dried
Vine morphology:
Shape of leaf	Heart shape	Dentate	Heart shape	Dentate	Elliptical
Color of tender leaf	Purple	Light green	Light green	Light green	Light green
Color of adult leaf	Green	Green	Green	Green	Green
Color of stem	Violet	Purple green	Green	Green	Green

2.5 Technologies that can be applied to increase vine and root yield

2.5.1 Selecting the appropriate variety

USE purpose	Spring crop	Winter crop
Dual purpose	Nr.8,KB1,KL5,KL6	Nr.8,KB1,KL5,KL6,Hoanglong
Forage purpose	Nr.8,KL1,KL5,KL6	Nr.8,KL1,KL5,KL6,Hoanglong

2.5.2 Planting season

Spring crop

Winter crop

Planting season

10 February-25 February

25 September-25 October

Favorable conditions

Unfavorable conditions

From planting to harvesting the temperature and moisture are fairly suitable for growing sweetpotato.
Need to avoid plants submerged in water and over-producing vines at the end of the season

At the start of winter high mois ture and temperature create good conditions for vine growth.
At the end of the dry season low temperature and moisture prevent good root development.

2.5.3 Soil characteristics

	Spring crop	Winter crop
Proper soil type	Mixed sandy, light loamy, riverside, gar den, along canals and dikes	Mixed sandy, light loamy, riverside, garden, along canal and dikes
Land type	High land, upland, well drained	High land, upland, and middleland

2.5.4 Soil preparation

	Spring crop	Winter crop
Requests and ways	Plough deep to prepare beds	Plough deep to prepare beds
Size of beds	1.1 -1.2m wide, 0.4-0.45m high	1.1 -1.2m wide, 0.4-0.45m high
Distance between beds	10-30 cm	10-30 cm
Direction of beds	East-West	East-West

2.5.5 Planting method

	Spring or winter crops
Vegetative multiplication	Cut 1st and 2nd sections for multiplication purpose. Plant in distance of 15x20 cm.
Multiplication method of planting material from root	Choose standard breeding roots and keep in the house. The shoots can be planted as planting material. Plant in density of 5-7 roots/m 2.
Preparation before cutting planting material	At least 45 days after multiplication, vines can be cut for planting.
Standards of good planting material	The 1st and 2nd section of an adult stem.
Method of cutting planting material	Depends on characteristics of the variety (selective cutting of vines from certain plants of each bed).
Length of stem (cm)	25-35
Number of nodes/stem	5-7
Planting method	One row in the middle of the bed
Density (stem/m of bed)	4-5

2.5.6 Fertilization

	Spring or winter crop
Ratio and total amount of fertilizers (kg/sao)	300 - 500 kg manure 4 - 5 kg urea (N) 12 - 15 kg Super phosphate (P) 4 kg potassium chloride (K)
Basic fertilization	Mix manure with P, put in the furrow and cover with soil from the bed. Then, top it off with 1 kg of urea.
First additional fertilization Timing Amount (kg/sao)	At 25 - 30 days after planting 2-3 kg urea mixed with 3 kg potassium chloride
Second additional fertilization Timing Amount (kg/sao)	At 2-3 days after pruning the stems 0.5-1 kg urea

2.5.7 Cultivation technology

	Spring crop	Winter crop
Pinching off young shoots	At 25-30 days after planting (several days before or after the 1 st additional fertilization) cut the tops to help branching and optimise vegetative development.	At 25 days after planting (several days before or after the 1 st additional fertilization) cut the tops to help branching and optimise vegetative development.
Re-mounding the bed for weed control	At 25-30 days after planting, hoe deeply into soil, turn up the bed slightly linking this activity with the 1 st additional fertilization. At 10-1 5 days after the 1 st addi tional fertilization, hoe, turn up soil slightly.	At 25 days after planting, hoe soil deeply, turn and earth up the bed slightly, in combination with the 1 st additional fertilization. At 10-15 days after the 1 st addi tional fertilization, hoe, turn slightly and earth up the bed highly.
Irrigation	Keep soil moist for 2-3 days after planting so that the stems can re- grow. Irrigate 2-3 days after turning up the bed and 1 st additional fertiliza tion application. At 45-50 days after planting if too much vine during the first period, some stems should be cut and stems should be lifted to break excessive roots.	Keep soils moist for 2-3 days after planting so that the stems can re- grow. Irrigate, flood 1/2-1/3 of the furrows, keep soil moist when weather is dry. At 45-50 days after planting if too much vine during the first period, some stems should be cut and stems should be lifted to break

2.5.8 The vine-cutting method for forage varieties

	Spring crop	Winter crop
First vine harvest
Time to start harvest Harvesting criteria	At 40-45 days after planting Cut 1/3-1/4 of the length of the longest vine	At 40-45 days after planting Cut 1/3-1/4 of the length of the longest vine
Subsequent vine harvests	Every 7-10 days after the first harvest depending on the rains.	Every 10 days after the first harvest depending on the rains.
	Cut 1/3-1/4 of the length of the longest vine.	Cut 1/3-1/4 of the length of the longest vine.
	Nitrogen should be added after each cutting (0.5 - 1.0 kg urea / sao).	Nitrogen should be added after each cutting (0.5 - 1.0 kg urea / sao).
	Cut stems every 10-15 days until the last harvest.	Cut stems every 10-15 days until the last harvest.
	Depending on vegetative growth, cut 2-3 longest stems, up to 4 stems if much growth, leaving 15-20 cm. More stems can be cut near the end harvest	Cut 2-3 longest stems of a plant, leaving 15-20 cm. Irrigate while applying additional fertilizer after cutting.

2.5.9 Main insects and protection

	Spring or winter crop
Weevil	Use traps (For example: chopped sweetpotato pieces) to lure adult weevils to come to lay eggs, then get the traps to kill larvae. Mound high beds and keep soil moist to reduce weevil damage. Use biological control such as introduction of natural enemies, manipulation of habitat, conservation of natural enemies through avoidance of pesticide use or trap weevils to eliminate them.
Sweetpotato Hornworm (Agnus convolvuli)	Sweetpotato rotating with paddy rice helps eliminate insects. Leaf-eating caterpillar can be caught by hand.
Scrap	Planting tolerant varieties is the best protection from scrap. Check and eliminate the attacked plants
Black rot	Restrict irrigation during the final period. Rotate sweetpotato with other crops in paddy fields, or plant on highlands.

2.5.10 Harvest

	Spring crop	Winter crop
Root harvest
Time to harvest	120 days after planting	100 days after planting
Day to harvest	Dry and sunny days	Dry and sunny days
Methods to harvest	Plough with buffalo or hoe. Avoid damaging roots	Plough with buffalo or hoe. Avoid damaging roots
Vine harvesting
Time to harvest	Start to harvest vine for animal feed at 45-50 days after planting	Start to harvest vine for animal feed at 45-50 days after planting
Day to harvest	Every 7-1 0 days after the first vine harvesting	Every 7-10 days after the first vine harvesting

2.5.11 Storage

	Spring or winter crop
Storage of roots
Methods to store roots	Clean soil or sand from roots, keep in dry, airy, and cool places
Some remarks during storage	Check regularly to eliminate rotting roots
Storage of vine
Methods to store vine	Drying or ensiling
Storage duration	3-4 months
Some remarks during storage	After 14 days ensiled feed can be fed to pigs. It can be stored for at least 4-5 months. It has the typical smell and taste of ensiled feed. Check the bags regularly to make sure of anaerobic condition to avoid rotting and molding.

2.5.12 Recommended utilization

	Spring or winter crop
Vine	The soft and sweet vine can be used as vegetable for humans or forage for animals
Root	Roots can be boiled or dried for human consumption or animal feed