African Journal of Pig Farming Vol. 1 (4), pp. 042-047, December, 2013. Available online at 
www.internationalscholarsjournals.org © International Scholars Journals 
 
 
 

 

 

Full Length Research Paper 
 

Seasonal changes in body condition scores of pigs and 

chemical composition of pig feed resources in a semi-

arid smallholder farming area of Zimbabwe 
 

Orbert C. Chikwanha
1
, Tinyiko E. Halimani

1
, Michael Chimonyo

2*
, Kennedy Dzama

3
 and 

Evison Bhebhe
4
 

 
1
Department of Animal Science, Faculty of Agriculture, University of Zimbabwe, 

P. O. Box MP 167, Mount Pleasant, Harare, Zimbabwe. 
2
Department of Livestock and Pasture Science, Faculty of Science and Agriculture, University of Fort Hare, P. Bag 

X1314, Alice 5700, Eastern Cape, South Africa. 
3
Department of Animal Sciences, Stellenbosch University, P. Bag X1 Matieland, South Africa. 

4
Department 

of Paraclinical Veterinary Studies, University of Zimbabwe, P. O. Box MP 167, Mount Pleasant, Harare,  
Zimbabwe. 

 
Accepted 23 August, 2013 

 
There are few studies quantifying the productivity of rural pigs and evaluating the nutritive value of 
non-conventional feeds, such as weeds. The objectives of this study were to determine changes in 
body condition scores of boars and lactating sows and investigate changes in the chemical 
composition of commonly used pig feed resources in a smallholder farming area of Zimbabwe. Body 
condition scores (BCS) were measured monthly between October and April. Commelina benghalensis 
(wandering jew) and Richardia brasiliensis (Mexican clover) were collected monthly, between October 
and March, for proximate and amino acid analysis. Sows had lower BCS than boars (P<0.05). The 
Neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents of C. benghalensis were lower 
(P<0.05) than those of R. brasiliensis. C. benghalensis had about twice the amount of crude protein 
(CP) compared to R. brasiliensis. Lysine, methionine and cysteine, which are the most important amino 
acids in pig nutrition, were similar in groundnut hulls and R. brasiliensis. C. benghalensis had higher 
(P<0.05) levels of threonine, tryptophan, isoleucine, leucine, histidine, phenylalanine, tyrosine, valine, 
arginine, serine, aspartic acid, glutamic acid, glycine and alanine than R. brasiliensis. The proportion of 
essential amino acids (EAA) was significantly higher (P<0.05) in R. brasiliensis. A further study to 
determine the digestibility and growth performance of pigs fed on these non-conventional diets is 
needed. 

 
Keywords: Rural pig production, body condition scoring, Commelina benghalensis, proximate analysis, 

Richardia brasiliensis 
 
 
INTRODUCTION 
 
Rural pig farmers in southern Africa rely on locally 

available feed resources to feed their animals. There is a 

general perception that feed supplies are seasonal and 
inadequate to meet pig maintenance and production feed 
 
 
 
*Corresponding author. E-mail: mchimonyo@ufh.ac.za 

 
 
 
requirements throughout the year in rural areas 
(Mashatise et al., 2005). However, there have been few 
attempts to quantify the productivity of local pigs, and the 
nutritive value of the common feeds that they consume, in 
order to improve smallholder pig production. It is as-
sumed that animal performance during the wet season is 
high (Mhlanga et al., 1999; Holness et al., 2005). The 
influence of the production systems that the farmers use 
has often been ignored. There has been inadequate re- 



Chikwanha et al.         042 

 
 
 

Table 1. Pig body condition scoring system used. 
 

Body condition score Description Assessment of fat cover 

0 Emaciated Exposed, no cover on bones 

1 Poor Bones prominent, little cover 

2 Moderate Bones easily felt without palm pressure 

3 Good Bones only felt with firm palm pressure 

4 Fat Bones cannot be felt with firm palm pressure 

5 Grossly fat Further deposition of fat impossible 

Source: Holness (1991).   
 
 
 
search on locally available, non-conventional feed resour-
ces and their potential value as pig feeds (Ly, 1993; 
Lekule and Kyvsgaard, 2003). Efforts have been put into 
utilising non-conventional feedstuffs for pigs, including 
legume tree leaves (Halimani et al., 2005), and maize 
cobs (Chimonyo et al., 2006; Chimonyo and Dzama, 
2007). Attempts should be made to identify locally avail-
able feed resources for each area. The lack of informa-
tion on changes in nutritive value during the growing sea-
son, when the bulk of the feeds are available, hampers 
the development of appropriate conservation strategies to 
maintain or produce pigs across the dry season, when 
both feed quantity and quality are low. Use of non-con-
ventional feed resources is particularly impor-tant since 
cereal grains are needed for human consump-tion and 
are not readily available for feeding pigs, espe-cially in 
rural areas of developing countries. There is a need to 
identify locally available non-conventional feed resources 
(for example weeds) for pigs and characterise their 
nutritive value including amino acid profiles. A ba-lanced 
and optimal proportion of amino acids are required for 
efficient protein deposition in the pig, along with a 
sufficient supply of energy (Grala et al., 1999; Kyriazakis 
and Whittemore, 2006). Nutritional status of rural pigs can 
be assessed by monitoring body weight changes and 
nutritionally-related blood parameters. Be-cause scales 
are often not available in rural areas, adap-tation of the 
body condition scoring system, widely used in cattle, has 
been successful in assessing the perfor-mance of pigs 
(Maes et al., 2004).  
The objectives of the current study were to determine 
changes in body condition scores of boars and lactating 
sows during the rainy season when feed is not likely to be 
a constraint, and investigate changes in the chemical 
composition of commonly used pig feed resources in a 
smallholder farming area of Zimbabwe during the rainy 
and post-rainy seasons. The hypotheses tested were that 
the body condition and chemical composition of the com-
monly used feed resources do not change with during the 
rainy ad post-rainy seasons. 

 
 
 
MATERIALS AND METHODS 
 
Study site 
 
The study was conducted in Chinyuni Ward of Chirumanzu district, 
in the Midlands Province, about 30 km to the north of Masvingo, 
Zimbabwe. It is located 19º34' S and 30º45' E, at an altitude of 
between 1300 to 1440 m above sea level. The district lies in Natural 
Region III, a semi-arid agro-ecological zone where farming opera-
tions are extensive. The area receives mean annual rainfall of 650 
to 800 mm. The mean maximum temperature ranges from 25 to 
39ºC in cold (May to August) and hot seasons (September to No-
vember), respectively. The area experiences frequent seasonal 
droughts and severe dry spells during the growing season, which 
makes it generally unsuitable for cropping. The farming systems are 
largely based on livestock and drought-resistant fodder and food 
crop production. 

 
Selection of pigs 
 
Forty-five lactating sows and 11 mature boars were selected for 
body condition scoring from 38 households. The sows were nursing 
piglets ranging from one week to three weeks old. Body condition 
scoring was done during the growing season (October 2005 to April 
2006), the period when the majority of the sows are lactating. The 
selection of households was based on farmers with at least one 
mature pig. Pig identification was reliant on farmers’ knowledge of 
their pigs, as is common practice in smallholder farming areas. 
These pigs were mostly free ranging and occasionally offered a 
supplementary diet of local feed resources when available. No 
commercial feeds, drugs or medicines were used but there was 
limited knowledge and use of ethno-veterinary medicine. The body 
condition scores (BCS) were measured using the scoring system 
from 0 to 5, as shown Table 1. The assessment was based on the 
fat cover on the spine and transverse spinal process, and was 
assessed at the end of the month. One trained person assessed the 
condition of the pigs throughout the study. 
 
 
Feed sample collection 
 
In a separate trial, the weeds commonly used by farmers in feeding 
their pigs were sampled for nutritive evaluation. The weeds, 
Commelina benghalensis (wandering jew) and Richardia brasilien-

sis (Mexican clover), were collected on a monthly basis from five 

crop fields of one hectare each every month from October 2005 to 

  



043          Afr. J. Pig Farming 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
Figure 1. Changes in body condition of pigs over time. 

 

 
March 2006. Samples were cut at a height of 50 mm above the 
ground, air dried for 14 days and ground through a 2 mm sieve and 
stored at air temperature to await analyses. The plants were picked 
from four quadrants from each of the fields, two at the end and two 
at the middle of the field. About 100 g of maize dried brewers’ grain 
and groundnut hulls were also collected every month throughout the 
study period from farmers’ households. 

 
Chemical analyses 
 
The dried brewers’ grain and groundnut hulls were analyzed for 
amino acid composition. Weed samples were analysed for dry 
matter (DM), crude protein (CP), ash and ether extract (EE) as 
described by AOAC (1990). Neutral detergent fibre (NDF) and acid 
detergent fibre (ADF) analyses were done according to the method 
described by Goering and Van Soest (1970). Amino acid profiles of 
R. brasiliensis, C. benghalensis and maize brewers’ dried grain and 
groundnut hulls were conducted at the Agricultural Research 
Council, Irene, South Africa. Amino acid analyses involved acid 
hydrolysis, pre-column derivatisation, separation by HPLC and 
detection using fluorescence detector, as described by Einarsson et 
al. (1983). Tryptophan was analysed using enzymatic hydrolysis, 
separation by HPLC and detection using fluorescence detector, as 
described by De Vries et al. (1980). Cystine was analysed as 
described by Gehrke et al. (1985). The protein value was estima-
ted by calculating the extent of deficit of each essential amino acid, 
in relation to that present in the ideal protein, using the egg as the 
standard.  

Gross energy of the feeds was determined using the bomb 

calorimeter at the Institute of Mining Research, University of Zimba-
bwe, using methods described by AOAC (1990). All analyses were 
performed in triplicate. 

 
 

 
Statistical analyses 
 
The BCS of the pigs were tested for normality, and were skewed, 
even after transformation; they were then subjected to the Fried-

man procedure (SAS, 1996) and analysed using the following linear 
model: 
 
Yij = µ + Mi + Eij; 
 
where: Yij = change in body condition score; µ = overall mean 

common to all observations; Mi = effect of the i
th

 month (October… 

April); Eij = random error distributed as N (0,I 
2

E).  
The nutrient compositions of the feed resources were analysed 
using the PROC MIXED procedure of SAS (1996). The linear model 
used was:  
Yijk = µ + Mi + Wj + Mi * Wj + Eijk; 
 
where: Yijk = Response variable (DM, CP, Ash, ADF, NDF and EE, 
amino acids); µ = Overall mean common to all observations; M i = 

fixed effects of the i
th

 month (October… April); W j = fixed effects of 

the j
th

 weed (j = C. benghalensis and R. brasiliensis); Mi * Wj= inter-
action of month and weed; Eijk = random error distributed as N (0,I 
2

E). 
 
Pair-wise comparisons between least square means were 

performed using the PDIFF statement in SAS (1996). 

 
RESULTS 
 
Body condition scoring 
 
Figure 1 illustrates the changes in the mean BCS for the 
lactating sows and boars. During October and November, 
the BCS of lactating sows were higher (P<0.05) than for 
boars. However, from December up to the end of the end 
of April, the BCS was significantly lower for lactating sows 
than boars. The sows maintained their condition during 
this period, while boars showed a marked increase 
(P<0.05) in condition. The main feeds that the pigs recei-
ved during trial period were groundnut hulls, brewer’s 
dried grain and weeds (C. benghalensis and R. Brasilien-
sis). The chemical composition of these feedstuffs was, 
therefore, evaluated. 
 
Dry matter, ether extract and ash contents 
 
Table 2 shows DM, EE, ash, NDF, ADF and gross energy 
contents of C. benghalensis and R. brasiliensis. Both 
month of sampling and species of weed influenced 
(P<0.05) chemical composition. Across the six months, R. 
brasiliensis had a significantly higher DM than C. ben-
ghalensis. Within each weed, DM content was constant 
(P>0.05) throughout the sampling period.  

Ether extract contents were significantly affected by 
month, weed species and the interactions between the 
two. As with DM, in R. brasiliensis EE content remained 

constant throughout the monitoring period. The EE con-
tent for C. benghalensis fluctuated but was consistently 
higher (P<0.05) than for R. brasiliensis. R. brasiliensis 
had treble the amount of ash (P < 0.05) compared to C. 



Chikwanha et al.         044 

 
 
 
Table 2. Dry matter (DM, g/kg), crude protein (CP) and ether extract (EE) content, ash, neutral detergent fibre (NDF), acid 

detergent fibre (ADF) (g/kg) and gross energy (GE) (MJ/kg) of Commelina benghalensis (CB) and Richardia brasiliensis 

(RB) on DM basis. 
 

Component      Month      

 Weed October  November December   January  February  March SEM 
DM CB 823.7

a
  823.0

a
 820.5

a
   825.8

a
  823.3

a
  821.3

a
 52.06 

 RB 873.4
b
  872.2

b
 868.4

b
   868.5

b
  872.3

b
  869.8

b
  

CP CB 208.6
b
  207.9

b
 218.6

c
   225.0

c
  227.3

c
  237.4

c
 15.42 

 RB 100.8
a
  106.3

a
 109.9

a
   104.8

a
  111.9

a
  134.7

a
  

EE CB 18.4
c
  18.5

c
 18.2

c
   18.7

cd
  19.3

d
  18.5

c
 0.21 

 RB 16.0
a
  16.2

a
 15.9

a
   16.5

b
  16.4

b
  16.2

a
  

Ash CB 22.6
a
  25.4

b
 23.9

a
   22.6

a
  23.8

a
  25.3

b
 1.90 

 RB 75.9
e
  65.2

cd
 63.7

c
   65.5

d
  62.8

c
  63.6

c
  

NDF CB 408.0
a
  403.8

a
 482.8

d
   401.9

a
  402.0

a
  411.6

a
 24.27 

 RB 492.0
c
  498.3

c
 471.6

b
   482.8

b
  470.0

b
  467.6

b
  

ADF CB 196.1
a
  195.2

a
 187.2

a
   184.8

a
  185.4

a
  188.0

a
 10.25 

 RB 389.1
b
  387.4

b
 391.9

b
   387.4

b
  388.9

b
  387.6

b
  

GE (MJ/kg) CB 13.1
c
  11.8

b
 14.4

c
   7.6

a
  14.9

c
  13.9

c
 1.16 

 RB 14.0
c
  16.0

d
 10.6

b
   14.2

c
  14.8

c
  15.7

d
  

 
abcd

 Values with different superscripts for each component are different (P < 0.05). 
 

 
benghalensis . The mean ash contents were 66.1 and 

23.9 g/kg for R. brasiliensis and C. benghalensis, res-

pectively. The ash content, however, did not show con-

sistent patterns within each weed. 

 
Neutral and acid detergent fibre contents and gross 

energy levels 
 
The NDF and ADF contents of C. benghalensis were 
lower (P<0.05) than those of R. brasiliensis. The diffe-

rences in fibre contents were more marked for ADF than 
NDF. R. brasiliensis had higher (P<0.05) energy levels 
than C. benghalensis . The highest gross energy levels of 
R. brasiliensis were recorded in November, while the 
highest gross energy levels for C. benghalensis were 

recorded in February. Brewers’ dried grain had the high-
est gross energy (19.3 MJ/kg), which did not vary across 
the sampling period. 
 
 
Crude protein and amino acid profiles 
 
As shown in Table 2, C. benghalensis had about twice 
the amount of CP than R. brasiliensis . The CP content 
remained constant at a mean of 108.1 g/kg for R. brasi-
liensis, but increased (P<0.05) from October to March for 
C. benghalensis. The highest CP content, observed in 

March, was 237 g/kg. The amino acid content of the 
feeds (weeds, brewers’ dried grain (BDG) and groundnut 
hulls (GNH) is shown in Table 3. Brewers’ dried grain had 
the highest CP content of 219.5 g/kg, followed by C. 

 

 
benghalensis, R. brasiliensis and groundnut hulls had the 
least CP content. Brewers’ dried grain had the highest 
concentration of most of the individual amino acids. 
Levels of lysine, methionine and cysteine, which are the 
most important amino acids in pig nutrition, were similar 
in groundnut hulls and R. brasiliensis. C. benghalensis 
had higher (P<0.05) levels of threonine, tryptophan, iso-
leucine, leucine, histidine, phenylalanine, tyrosine, valine, 
arginine, serine, aspartic acid, glutamic acid, glycine and 
alanine than R. brasiliensis. The proportion of essential 
amino acids (EAA) was significantly higher (P<0.05) in R. 
brasiliensis. No differences (P>0.05) existed in the ratio 
between EAA and non-essential amino acids (NEAA) 
between C. benghalensis and groundnut hulls. Levels of 
HO-proline were less than all other amino acids in all 
feedstuffs.  

Table 4 shows the protein value of selected essential 
amino acids in the four feeds. The values for lysine, 
methionine, cysteine, threonine and isoleucine were high-
est for brewer’s dried grain. The C. benghalensis had 

higher (P<0.05) values for these amino acids than 
groundnut hulls and the highest tryptophan value of the 
four feeds. 

 
DISCUSSION 
 
Although the use of body condition scoring in assessing 
nutritional status of pigs is not common, it has been 
shown to correlate well with the total amount of body fat 
(Maes et al., 2004). Measurement of back fat levels con-
stitutes an important tool to evaluate the total amount of 

  



045          Afr. J. Pig Farming 
 

 
 

Table 3. Amino acid content (g/kg) for Commelina benghalensis, Richardia brasiliensis, brewers’ dried grain 

(BDG) and groundnut hulls (GNH). 
 

Amino acid R. brasiliensis C. benghalensis BDG GNH SEM 

Lysine 6.7
a
 9.0

b
 11.2

c
 6.8

a
 0.76 

Methionine + Cysteine 2.9
a
 3.1

a
 11.1

b
 2.2

a
 1.82 

Threonine 3.0
a
 4.6

b
 7.4

c
 2.9

a
 0.55 

Tryptophan 1.1
a
 2.6

b
 1.3

ab
 0.8

a
 0.08 

Isoleucine 3.9
a
 5.6

b
 10.3

c
 3.7

a
 0.67 

Leucine 6.1
a
 9.0

b
 30.5

c
 6.0

a
 0.85 

Histidine 4.2
a
 5.1

a
 12.3

b
 4.1

a
 0.45 

Phenylalanine + Tyrosine 8.1
a
 11.9

b
 36.6

c
 8.7

a
 0.96 

Valine 4.4
a
 6.1

b
 11.6

c
 4.4

a
 0.53 

Arginine 4.2
a
 7.6

b
 10.1

c
 5.6

a
 1.12 

Serine 3.2
a
 5.3

b
 9.7

c
 3.5

a
 0.62 

Aspartic acid 8.9
a
 21.4

c
 12.8

b
 9.6

a
 1.46 

Glutamic acid 7.8
a
 12.7

b
 36.7

c
 8.0

a
 0.86 

Glycine 3.5
a
 5.3

b
 7.2

c
 3.3

a
 0.37 

Alanine 4.0
a
 6.2

b
 15.6

c
 3.2

a
 0.42 

Proline 3.1
a
 5.0

b
 16.5

c
 5.1

b
 0.53 

HO-Proline 0.4
a
 0.7

a
 0.7

a
 2.8

b
 0.26 

EAA: NEAA 1.04
c
 0.92

b
 0.84

a
 0.93

b
 0.05  

abcd
 Values with different superscripts within row differ (P < 0.05). 

 

 
Table 4. Protein value of R. brasiliensis (RB), C. benghalensis (CB), and brewers’ dried 

grain (BDG) and groundnut hulls (GNH). 
 

   Protein value   

Amino acid RB CB BDG GNH SM
1
 CM

1
 

Lysine 9.6
a
 12.9

b
 16.0

b
 9.7

a
 17.1 25.7 

Methionine + Cysteine 7.3
b
 7.8

b
 27.8

c
 5.5

a
 30.0 30.0 

Threonine 6.7
a
 10.2

b
 16.4

c
 6.4

a
 26.7 31.1 

Tryptophan 7.3
b
 17.3

c
 8.7

c
 5.3

a
 26.7 33.3 

Isoleucine 9.8
a
 14.0

b
 25.8

c
 9.3

a
 35.0 35.0 

 
1
Protein values for sunflower meal (SM) and cottonseed meal (CM) were derived from 

Kyriazakis and Whittemore (2006). 
abcd

 Values with different superscripts within row differ 
(P < 0.05). 

 
 
of body fat, especially in rural areas where weighing sca-
les, among other important equipment, are rarely availa-
ble. Maes et al., (2004) also showed that the number of 
stillborn piglets increased with decreasing back fat 
thickness at the end of gestation.  
The marked decline in BCS values for lactating sows 
from October onwards indicates that most of them recei-
ve inadequate nutrient during confinement. During con-
finement, the pigs were supplied with feed once a day 
(Chikwanha, 2006). The steady decline in the condition of 
the lactating sows is as a result of suckling. In Chiru-
manzu district, as in many other rural areas of southern 

 
 
Africa, pigs scavenge for feeds during the dry season, 
and are confined during the rainy season to prevent them 
from destroying field crops (Mashatise et al., 2005; Chik-
wanha, 2006). The commonly held view that pigs get 
adequate nutrients during the rainy season does not 
apply in Chirumanzu. The reasons why boars had low 
BCS in October is not clear. It could be possible that 
boars mate more females than is recommended, since 
the boar to sow ratio is extremely low in rural areas 
(Chiduwa, 2006). There is a need to conduct more stu-
dies in characterizing rural production systems to develop 
sustainable and profitable pig enterprises that reduce po- 



Chikwanha et al.         046 
 
 

 
verty among the poor. The steady increase in condition of 
boars from December indicates that nutritional status was 
improving, suggesting that their maintenance and produc-
tion nutrient requirements were easily met during confine-
ment.  

The nutritional quality of the commonly used feed 
resources was evaluated for their chemical composition. 
The feed resources that were predominantly fed to pigs 
throughout the year included C. benghalensis, R. brasi-
liensis, maize suckers, kitchen swill, maize cobs, vegeta-
bles, groundnut hulls, watermelons, hominy chops, brew-
ers’ dried grain, pumpkins and some unidentified weeds. 
However, the chemical composition and amino acid 
profiles of the other feed resources are available in the 
literature, and for this reason only C. benghalensis, R. 
brasiliensis, brewers’ dried grain and groundnut hulls 
were collected and analysed.  

The observation that R. brasiliensis had a significantly 
higher DM than C. benghalensis was expected. C. Ben-
ghalensis is a watery weed that has no distinct stem. The 
lack of month effects on the DM content within each weed 
demonstrates the high potential of these weeds as 
livestock feeds as most forages show an increase in DM 
as the season progresses (Soest, 1987). Ether extract 
contents also remained constant across the trial period. 
C. benghalensis had a consistently higher EE content 
than for R. brasiliensis , suggesting that the former con-
tains a higher capacity to supply energy to pigs. On the 
other hand, R. brasiliensis had markedly higher ash con-
tent than C. benghalensis. These findings suggest that 
both weeds can complement each in supplying adequate 
nutrients to pigs (Halimani et al., 2005).  

As expected, there was a considerable increase in fibre 
content for both weeds as they matured, which can have 
serious implications on the intake and digestibility of 
forages (Van Soest, 1987). However, local pigs have the 
capacity to utilize diets with higher fibre content than 
European breeds, such as the Large White (Kanengoni et 
al., 2002; 2004). The marked difference between the two 
weeds in fibre content should be noted. Differences in 
gross energy levels were also observed. However, there 
is need to determine the digestibility and utilization of the 
nutrients.  

The relatively high CP content of the feeds under inves-
tigation imply that these weeds can be conserved for dry 
season of feeding pigs, and be used as protein supple-
ments. This would require harvesting the weeds during 
the rainy season or to conserve them through silage or 
hay making. Interestingly, C. benghalensis has a relative-
ly higher CP than most leguminous leaf meals.  

The high CP levels of BDG agree with the study of Yaa-
kugh and Tegbe (1990), who obtained 21% CP. The high 
CP levels of BDG agree with the study of Yaakugh and 
Tegbe (1990), who obtained 21% CP. The resultant ami-
no acid products are either end products of bacteria or or 
other micro-organisms produced during the fermentation 

 

  
 
 
 
process, or from microbial matter attached to fibres in the 
brewers’ grains. Our findings are consistent with those of 
Varvikko (1986), who demonstrated that resi-dues of 
vegetable feed supplements in nylon bags could be 
markedly contaminated by microbes during rumen 
incubation. Fermentation during the brewing process mi-
mics rumen fermentation and, therefore, has a better 
amino acid profile.  

Tryptophan quantities in R. brasiliensis and brewers’ 
dried grain fall in the lower range of requirements for 
weight gain and feed efficiency for pigs. The required 
levels range from 0.13 to 0.19% (NRC, 1998). However, 
C. benghalensis has a surplus of tryptophan. The amino 
acid profile for C. benghalensis and R. brasiliensis exhibi-
ted the usual profile of green plants (D’Mello, 1995), 
whereby the ratio of glutamic acid and aspartic acid are 
higher in both weeds in comparison to the other amino 
acids. The high amino profile was expected since brew-
ers’ dried grain is an end product of microbial fermenta-
tion and is most likely to have higher nutrient concentra-
tion as compared to the other feeds. The quantities of as-
partic and glutamic acid were highest in C. benghalen-sis, 
R. brasiliensis and groundnut hulls. Although, the feeds 
tested have reasonably high levels of CP, all the 
individual essential amino acids are below the ideal re-
quirements (Holness, 1991). Brewers’ dried grain had an 
essential amino acid to non- essential amino acid (EAA: 
NEAA) ratio almost similar to that observed by Wang and 
Fuller (1989) for optimum dietary amino acids for growing 
pigs.  

Yaakugh and Tegbe (1990) reported on the use of BDG 
as a potential feed for pigs. The high nutritive value of 
BDG makes it a more appropriate option for farmers and 
will also serve to reduce the competition for the same 
feed resources, especially cereals, between humans and 
pigs. The high protein content of C. benghalensis can 
complement the high- energy content in BDG. The supply 
of BDG is, however, intermittent since their availability 
depends on the number of people participating in brew-
ing. Usually each household brews beer about four times 
a year and produces an estimated 25 kg of brewers’ grain 
each time and, therefore, with these quantities it can only 
be used to alleviate food shortages. C. benghalensis and 
R. brasiliensis are troublesome weeds that need remov-
ing. Feeding them to pigs repays the labour involved and 
provides useful feed. The integration of animal production 
using agricultural by- products ensures that animals play 
a complementary role, rather than a competitive role with 
man in meeting their feed requirements. The use of diver-
se feed resources will ensure that pigs are able to meet 
their feed requirements (Kyriazakis and Whitte-more, 
2006).  

Of the four feedstuffs tested, brewers’ dried grain had 

slightly higher amino acid content than the other 

fermentation high potential as alternative feed resources 

for pigs. The low amino acid content does not meet the 



047          Afr. J. Pig Farming 
 
 
 
optimal pattern of essential amino acids required in the 
diet for efficient protein deposition in the pig (Grala et al., 
1999) . However, in terms of protein value (PV), the four 
feeds have relatively lower PVs in comparison to both 
sunflower meal and cottonseed meal (Kyriazakis and 
Whittemore, 2006) as shown for some of the individual 
essential amino acids. From these findings, it can be 
seen that BDG is close to those of sunflower meal and 
cottonseed meal. Although weeds have a relatively low 
PV, under smallholder conditions they are usually fed 
fresh to the pigs. The only major limitation when fed fresh 
is the high water content, which can reduce intake (Ly, 
1993). There is now a need to conduct further research to 
assess the performance when pigs are given the weeds 
fresh, rather than dry. 
 
Conclusions 
 
Lactating sows lost body condition during the rainy 
season. The feeds tested are not able to meet the amino 
acids requirements for growth. Therefore, there is a need 
to include these feeds in least cost feed diet formulation 
based on the use of locally available feed resources. 
There is also a need to conduct digestibility and growth 
performance trials with pigs fed on the non-conventional 
diets. 

 
ACKNOWLEDGEMENTS 
 
We thank farmers in Chirumanzu district for co-operating 
and keeping records for their pigs. Funding was provided 
by the Regional Universities Forum for Capacity Building 
in Agriculture (RUFORUM) Grant Number 2005 RU CG 
018. We also thank the Department of Livestock Produc-
tion and Development, Government of Zimbabwe, for 
participating in the project. The amino acid profiles were 
analysed at the Animal Nutrition Institute at the Agricul-
tural Research Council, Irene, South Africa. 

 
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