This dissertation is the product of two behaviour studies and an in vitro fermentation trial. Both behaviour studies were conducted at the Ashburton Racehorse-Training Centre in Ashburton, near Pietermaritzburg in KwaZulu- Natal. The first behaviour study evaluated differences in behaviours obtained through feeding either twice or four times daily. This trial showed (P<O.OO1) that horses fed twice a day spend a greater proportion of their day in stereotypic or vice-like behaviours. Horses eating four times a day ate less hay (P<O.OO1) and more concentrate (P<O.05) than horses being fed twice a day. Horses in both yards ate more hay (P<O.05) when exercise intensity was increased. Defecation frequency was higher on days when exercise intensity was high (P<O.05) and in the yard where horses were fed four times per day (P<O.O1). Faecal weight was greater (P<O.05), horses lay down more frequently (P<O.05), spent more time eating concentrate (P<O.OO1) and less time eating hay (P<O.OO1) when horses were fed four times per day. Fillies spent more time (P<O.05) eating hay than geldings. The second behaviour study was conducted within one yard only and considered the effects of changes in management strategies on the incidence of stereotypic behaviour. The results did not indicate that changes in management related to exercise intensity would have an effect on behaviours exhibited. However this trial did demonstrate that a reduction in feed intake on days when exercise is reduced will reduce the incidence of stereotypic behaviours. Horses reduced the time spent eating hay when exercise was reduced except that when feeding frequency was reduced in conjunction with reduced exercise, more time was then spent eating hay (P<O.OO1). It was found that fillies spent more time licking surfaces (P<O.OO1) and weaving (P<O.O1) than geldings, which were more aggressive (P<O.OO1) and ate more bedding (P<O.05) than the fillies. All the horses were more alert (P<O.OO1) on days of moderate exercise except when feed was reduced in conjunction with reduced exercise, so that horses were less alert (P<O.OO1) and more time resting (P<O.OO1). The in vitro study was conducted at the department of Animal and Poultry Science at the University of KwaZulu-Natal, Pietermaritzburg. This was a dilution trial, using different ratios of maize and Eragrostis curvula. It was shown that as the proportion of maize in the ration was increased so the digestibility and the degradability of the ration increased (P<O.OO1). It was also shown that the adapted two stage digestion techniques described by Tilley & Terry (1963) had lower supernatant pH levels than the samples that underwent microbial digestion only. This was accounted for by a problem with the methodology. The trial had hoped to show a dramatic decrease in pH and increased rates of gas production when the maize portion of the sample was increased. From the results established during this trial it is clear that application exists in the adoption of this method in in vitro feed analysis in the horse industry.· The behaviour studies significantly linked the incidence of stereotypic behaviour to feeding and nutritional management in racehorses. Some explanations of the noted behaviours can be elucidated through the development of in vitro protocols, where hindgut pH, degradability and fermentation of different ration mixtures elicit responses in physical terms. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

This study presents a production function analysis of fresh milk producers in the Highlands of Eritrea for the year 2002, dealing with the most important factors of production. Most dairy farmers are located in the Central Zone and Southern Zone (Mendefera and Dekemhare) areas of the Highlands of Eritrea. To ensure representative production functions, the Highlands of Eritrea were divided into three respectively homogenous study areas, namely Central Zone, Mendefera and Dekemhare. Most data for this study were collected by survey using a questionnaire, as dairy farms' recorded data were scarce. The annual milk yield record and purchased concentrates per farmer were obtained from their respective milk collecting centres and Dairy Associations belonging to each study area. Basically, an attempt was made to pool the data of the three study areas, using dummy variables to test if the three study areas' regressions have a common intercept and a common slope. However, from the analysis, the intercept and slope dummy coefficients for the pooled data were found to be statistically significant at the 1 % and 5% levels of probability. Thus, it was not economically as well as statistically practical to pool the three areas' data to determine a common function that represents the sample dairy farmers of the Highlands of Eritrea as a whole. For this reason, a separate analysis was conducted for each study area. The analysis used the Cobb-Douglas function (double-log) form using multiple regressions. However, while analysing the data using ordinary least squares (OLS) regressions, strong intercorrelations were encountered among some factors of production. These intercorrelations resulted in some of the parameters having negative production coefficients where, a priori, all such coefficients are assumed to be non-negative. Thus, to tackle the multicollinearity problem, a ridge regression technique was used at different levels of the biasing constant, c, where the regression coefficients in the ridge trace start to stabilize and the variance inflation factor (VIF) of each parameter and the average of the VIFs are close to one. The final fitted model includes those variables, which were significant at the 1 % and 5% levels of probability. However, for the Mendefera study area those variables significant at 10% level of probability were included as their t-statistic values were considerably greater than one and nearly significant at the 5% level of probability. From the regression coefficients of the final fitted model for each study area, the elasticities of production with respect to the factors of production, ceteris paribus, were estimated. The highest response in production to a one percent change, ceteris paribus, is due to milking cows followed by concentrates and labour for the Central Zone Dairy farmers . However, for the Southern Zone (Mendefera and Dekemhare) the highest response next to milking cows came from forage and labour. The regression coefficients of all the factors of production in each study area were greater than zero and less than one, implying rational use of the resources. However, the sum of the elasticities of production was found to be greater than one for each area of production, indicating increasing returns to scale. Components of the production function and cost calculations including marginal product (MP), values of marginal product (VMP), marginal rate of substitution (MRS), least-cost combinations of inputs, profit maximizing combinations of inputs and the short-run cost functions for each category within the sample of dairy farmers in each study area were estimated. All the VMP's of the resources for the Central Zone dairy farmers were found to be greater than the corresponding unit price of the resources. This implies that the resources are utilized inadequately. However, for the Southern Zone (Mendefera and Dekemhare) the variable concentrates is over-utilized, as the VMP is less than the unit price of the input. The marginal rate of substitution of concentrates for forage, ceteris paribus, showed that the Central Zone sample dairy farmers were utilizing the two resources almost equally. But for the Southern Zone sample dairy farmers the MRS of the mentioned resources showed a higher dependence on concentrates than forage. From the least-cost combination of concentrates and forage analysis it was found that none of the sample of dairy farmers was allocating resources on a least-cost basis. The profit maximizing combination of inputs showed generally a considerable improvement of milk yield and margins for all the sample of dairy farmers relative to the present situations. However, the profit maximizing criteria (i.e. VMPx = Px), assumes perfect knowledge, a risk free environment and competitive marketing systems. This has to be considered when advising sample farmers as to the optimal combination of concentrates and forage. The short-run cost function also indicates use of resources at below optimum levels. When the average variable cost of the resources is less than the unit price of output, then use of the resources is in the rational area of production. Based on the analysis of the three study areas, the average variable cost of the lower one-third group of sample dairy farmers of the Southern Zone was found to be greater than the unit price of output. This means that the farmers were not covering the short-run costs of production. The MC of concentrates for the lower one-third group of sample dairy farmers was found to be greater than the price per litre of fresh milk in the Southern Zone. This implies more than optimum use of the input (i.e. where MC = Py). / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.

The effect of untreated roughages on digestibility and rumen fill of the gut was reviewed as physical mechanism influencing the regulation of roughage intake. The review of literature also focused on identifying factors that affect the way in which urea-ammoniation alters the roughage intake, digestibility and performance of ruminant animals. Trials were carried out with fistulated cows to address to what extent concentrate proportion and urea-ammoniation affected microbial colonization and degradation of roughage diets in the rumen. One interest of this study was to develop a model that would help to predict the benefit associated with urea-treatment of roughages. The first trial (Chapter 3) investigated the effect of urea-ammoniation of roughage and concentrate proportion of the diet on degradation of roughages, and the benefit associated with the treatment of roughages. Four rumen-fistulated Jersey cows were fed on a basal diet composed of either urea treated (3 kg of urea per 100 kg of straw) or untreated Eragrostis curvula hay. These basal diets were supplemented with concentrate composed of maize meal (78%) and cotton seed cake (22%). The concentrate contributed 0, 25, 50 and 75% of the total ration and hay the rest. The experiment consisted of 6 periods. Each period lasted 19 days, comprising 12 days of adaptation to the experimental diet followed by 6 days degradability measurements and 1-day rumen fluid collection. During each period the 4 Jersey cows were randomly allocated to 4 of the 8 dietary treatments, ensuring that each diet was fed to 3 animals during the entire experimental period. The experimental roughages used in this trial were wheat (Triticum sativum) straw, barley (Hordeum Vulgare) straw, coastcross (k11) (Cynodon hybrid) hay, veld hay (natural grass), oat (Avena sativa) straw, oat (Avena sativa) hay, maize (Zea mays) stover, kikuyu (Pennisetum clandestinum) grass, weeping love grass (Eragrostsis curvula) and Italian rye (Lolium multiflorum) grass. Each roughage (sample) was subdivided into two equal portions, one of which was then treated with urea. The urea solution was prepared by dissolving 30 g of urea in 0.4 liter of water. The solution was fully distributed over I kg of roughage. Treated roughages were sealed tightly and stored at room temperature for 5 weeks in plastic bags. Immediately after opening, the different roughages, including the untreated ones, were sun dried, chopped fine by hand and ground through a 2-mm screen in a laboratory mill. About 3 g of each sample was weighed into labeled nylon bags. The bags were tied to a stainless steel disc with 10 evenly spaced small holes drilled through the periphery of the disc serving as anchor points. The bags were incubated (in duplicate per time interval) in the rumen for 120, 96, 72, 48, 24, 12, 6 and 3 h, sequentially. The treated samples were incubated in animals fed treated hay, while untreated samples were incubated in animals given untreated hay. Immediately after removal from the rumen, the bags, including the 0 hour ones, which had not been incubated but soaked in warm water for I hour, were washed in 6 cycles (each lasting 4 minutes) in a semi-automatic washing machine. The washed bags were then dried in a forced draught oven at 60 degrees C for 48 hours, cooled in a desicator and weighed. The pH of the rumen fluid ranged between 6.5 and 6.8 for all diets. Rumen ammonia concentration was higher (P<0.002) when the basal diet consisted of urea treated hay. Increasing the concentrate proportion in the diet had the desired effect of increasing rumen ammonia concentration without severely affecting pH. Urea-ammoniation increased (P<O.OOO1) the slowly degradable fraction (B), potential degradability (PD), effective degradability (ED) of dry matter and neutral detergent fiber (NDF), decreased (P>0.05) lag time (LT) but had no effect on the rate of degradation (c) of dry matter. Concentrate proportions affected (P<0.05) the slowly degradable fraction, potential degradability, lag time and effective degradability but had no effect (P>0.05) on the rate of degradation of dry matter (DM). Maximum and minimum values of the slowly degradable fraction, potential degradability and effective degradability of DM and NDF were obtained at the 25 and 75% concentrate levels, respectively. Within urea-ammoniation, roughage type affected (P<O.OO1) the B-fraction, PO and EO of OM and NDF degradation. Rate of degradation of DM of untreated roughages varied from 0.022 h(-1) in wheat straw to 0.087 h(-1) in rye grass, while for urea treated roughages it varied from 0.022 h(-1) in oat straw to 0.082 h(-1) in rye grass. Rye grass degraded almost three to four times faster than urea treated oat or untreated wheat straw. Urea-ammoniation was less effective in increasing DM and cell wall degradation rates (c) of rye grass compared to wheat straw. The results showed that low quality roughages such as wheat straw benefited relatively the most from urea-ammoniation. The effect of urea-ammoniation and dietary manipulation on microbial colonization (Chapter 4) of fiber particles in the rumen of animals was also investigated in two experiments. In Experiment 1, the cows were fed on rations comprising either urea-ammoniated or untreated Eragrostis curvula hay supplemented with concentrate at hay to concentrate ratio of 100:0, 75:25, 50:50, 25:75, resulting in eight different rumen environments. The experiment consisted of two periods. Each period lasted 12 days of adaptation to the experimental diet followed by one-day incubation of urea-ammoniated and untreated barley straw. Experiment 2 consisted of two urea-ammoniated (7.5 kg of urea per 100 kg of hay) hay levels (20 and 40% of the total ration) and concentrate levels (60 and 80%). Fistulated Jersey cows were adapted for 12 days after assigning to the dietary treatment. Feed was given at the rate of 9.0 kg day(-1) per animal portioned into equal meals of 4.50 kg each and offered at 08:00 and 16:00 every day. About 3 g of urea-ammoniated or untreated barley (Hordeum vulgare) straw, ground through a 2-mm screen, was weighed into a labelled nylon bag and incubated for 3, 6 or 12 h in the rumen of the fistulated cows. Microbes adhering to incubated fiber particles were examined under the Environmental Scanning Electron Microscopy (ESEM) and analysed on the image analyser. Depending on morphology , the microbes were divided into three groups: bacilli (rod), cocci (round) and others (spiral, fimbrea and cluster ; not specifically defined or undefined microbes). Urea-ammoniation of dietary roughage decreased (P<O.OO1) bacilli counts and total bacteria count but had no effect on count of the undefined group of microbes on fiber particles in the rumen of cows (Experiment 1). Concentrate proportions had no effect (P>0.05) on bacilli, cocci and total bacterial count on fiber particles. However, the results from electron micrograph observations revealed that the total bacterial count tended to decrease as the concentrate level increased in the diet of cows. Bacilli, cocci, undefined group of microbes and total count of microbes increased (P<0.05) as length of incubation increased. In Experiment 2, incubated feed, concentrate proportion and time of incubation had no effect (P>O.05) on bacilli , others (undefined group of microbes) and total count of fiber-adhering microbes in the rumen of cows. However, increasing concentrate in the diet of cows tended to decrease (P<O.07) the count of fiber-adhering cocci. The total count of microbes on fiber particles was higher in animals fed 80% concentrate as compared to 60% concentrate. The benefit derived from urea treatment in terms of B-fraction, effective degradability and potential degradability of DM and fiber of roughages increased with increasing the NDF content. Therefore, the important conclusions drawn from the results of the present study is that urea-ammoniation of roughages should be done strategically and that high quality roughages may give little return per unit of cost of ammoniation. This means that the benefit associated with urea-ammoniation would be justified for poor quality roughages only. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2003.

Nematode parasites have become the biggest problem for small ruminant production in South Africa due to their resistance to the commercial anthelmintics. Notable, wattle tannin has been used as an alternative strategy for control. However, the concentration and the frequencies can likely influence its effect on the parasites control. The objective of this study was to determine the degree of pasture infestation and nematode infection in sheep and goats, as well as investigate nematode resistance to the anthelmintics, and the potential of wattle tannin in nematode control. The first study dealt with the epidemiology of internal parasites. Eight Merino ewes and eight Nguni does averaged 7-18 months of age were observed for 1 year during the months of February 2008 to January 2009 at the University of KwaZulu-Natal Research Farm (Ukulinga). Egg count per gram (EPG) and coccidian oocysts per gram (OPG) were counted according to Mc Master Technique (Hansen & Perry, 1994) by magnifying parasitic eggs from monthly rectal faecal samples dissolved in saturated sodium chloride. Faecal samples also were cultured for 15 days to identify infective nematode larvae (L3) using Baermann technique. Herbage samples were collected monthly from four paddocks as well to count L3 on the pasture. Sheep live weight was also recorded monthly. Seasonal effects was significant (P<0.05) on the EPG, OPG, faecal culture L3 and pasture L3. A higher level of infection was observed in summer (wet) than in winter (dry season). Trichostrongylus spp larvae were the most prevalent larvae (26.5%) while Strongyloides, Haemonchus contortus, Nematodirus and Cooperia spp occurred in the faecal culture by percentage of 20.9%, 16%, 16% and 14.5%, respectively. For parasite resistance, Ivermectin 1% (IVM), Closantel 5% (CST) and a combination of Abamectin 0.08% and Praziquantel 1.5% (CPA) were evaluated. Twenty four sheep (12 females and 12 males) aged between 7-18 months were used for 21 days. Animals were naturally infested by gastro-intestinal parasites. EPG and faecal culture L3 were counted on day 0, 7, 14 and 21. Closantel was the most effective. Haemonchus spp. were least affected whilst Trichostrongylus spp. were the most affected by all drugs. In the third study, wattle tannins were evaluated as an alternative nematode control drug. Three experiments (Exp.) were conducted to determine the effect of tannin concentration (Exp.1 and 2) and frequency (Exp.3) on nematode parasites. In Exp.1, 0, 0.8, 1.6 and 2.4 g tannin/kg BW were drenched for three consecutive days per sheep (16 females and 8 males, aged 8-9 months) for 21 day. In Exp.2, 30 sheep (14 males and 16 females, aged 9-18 months) were randomly allocated into three tannin treatments (0, 0.8 and 1.6 g tannin/kg BW) and drenched for a day. In Exp.3, 26 sheep (11 males and 15 females aged 9-18 months) were divided into three groups of 9, 9, and 8 sheep each. These groups were drenched with 1.6 g tannins/kg BW/day; once, twice or thrice for the 3 groups respectively. For the three experiments, EPG and L3 larvae were counted in individual feacal samples. For all tannin treatments, EPG decreased (P<0.05) over time. Though the differences among tannin levels and frequencies varied (P<0.05) over time, EPG consistently decreased with increasing tannin level and frequency. Thus 1.6 and 2.4 g tannin /kg BW for 3 consecutive days had nearly similar effects on the EPG. The results of this study are rather inconclusive that weather conditions such as rainfall had a direct effect on internal parasites development. Nematode parasites at Ukulinga Research Farm were resistant to the commercial anthelmintics used. Drenching with 1.6g wattle tannin/kg BW over three successive days is enough to reduce EPG and reduce the degree of pasture contamination. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

The impact of within-litter weight variation on the productivity of pig enterprises is poorly understood. The objective of the study was to determine the effect of within-litter birth weight variation on litter performance at three weeks of age and at weaning. The study was conducted using records from 1 788 litters, collected between January 1998 and September 2010, from a pig herd at the Agricultural Research Council (ARC), Irene. The records consisted of piglet identity, breed of sow, breed of boar, parity number, date of farrowing, number of piglets born alive (NBA), individual piglet weight at birth, three weeks and at weaning. From these records, mean birth weight (MBWT), litter weight at birth (TBWT), within-litter birth weight coefficient of variation (CVB), minimum birth weight (MinB) and maximum birth weight (MaxB) were calculated. Mean weight at three weeks (MWTT), litter weight at three weeks (LWTT), within-litter weight coefficient of variation at three weeks (CVT), percent survival to three weeks (SURVT), mean litter weaning weight (MWWT), litter weight at weaning (LWWT), within-litter weaning weight coefficient of variation (CVW) and percent survival at weaning (SURVW) were computed as derivatives. The factors affecting CVB were analysed using the General Linear Model procedures (SAS, 2008). For the relationships between CVB and litter performance at three weeks and weaning, PROC STEPWISE was used. The PROC REG (SAS, 2008) was then used to test whether the relationships between CVB and CVT, SURVT, MWTT, LWTT, CVW, SURVW, MWWT, LWWT and LWWT. Multiparous sows farrowed litters with higher (P<0.05) CVB than gilts. The litter weight (TBWT) and NBA, fitted as covariates, also affected (P<0.05) CVB. The correlation between CVB and NBA was 0.30. The CVB had a linear relationship (P<0.05) with SURVT (SURVT = 83.21 - 0.20 CVB), CVT (CVT = 16.71 + 0.50 CVB), SURV (SURW = 87.9 – 0.04CVB) and CVW (CVW= 15.8 + 0.5CVB). An increase of CVT with CVB depended on parity (P<0.05). The rate of increase of CVT with CVB was highest in Parity 1 (b=0.41) followed by Parity 2 (b=0.36) then middle aged (Parity 3-5) sows (b=0.32). The CVB had no effect on MWTT, LWTT, MWWT and LWWT (P>0.05). The CVB was shown to be an important determinant of SURVT and SURVW. A uniform litter at birth is likely to lead to a homogenous litter at three weeks and weaning, thereby reducing costs of production. Pig producers should, therefore aim at producing homogenous litters at birth. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

The most successful method used for improving the growth rate of broilers is genetic selection. Improvements in nutrition, housing and disease resistance have been impressive, yet genetic selection is purported to have contributed the majority of the tremendous increase in growth rate that has taken place over the past 50 years (McKay, 2008). Many selection strategies are available, but not all are suitable, as the choice is dependent on the objective of the breeder. Selection strategies are bound to change over time as different traits become more important, and this has been the case in the broiler industry: focus was initially placed predominantly on growth rate, but the negative genetic correlation that exists between growth rate and reproductive and liveability traits has forced breeders to change their position, especially as growth rate has almost reached its upper limit and reproductive traits lag behind. This has resulted in a change from single trait to multiple trait selection. In the exercise reported here, four selection strategies commonly used for single trait selection, namely individual, between family, within family and family-index selection, were applied to a simulated broiler population using the Monte Carlo method of simulation, and constructed with the use of genetic parameters obtained from the literature. Theoretical and simulated methods of the four selection strategies were compared. A fifth selection strategy, index selection, was applied to represent multiple trait selection. The relative merit of each selection procedure was then compared, as well as the results obtained from the theoretical and simulated methods. Construction of the selection index was complex in comparison to single trait selection, as each trait included in the index had to be assigned an economic value. This value is representative of the relative importance of that trait to the overall profitability, or ability to save costs in the operation. Therefore traits favourable to profitability, or having the ability to reduce production costs, are given a heavier weighting and will consequently achieve a relatively larger improvement when applied to the selection index. A model was constructed using production rates, income and costs to represent the current overall economic situation in the industry. This was then used to determine cost economic values, which represent the saving in cost per unit improvement in each of the economically important traits, and revenue economic values, calculated as the value of each unit improvement attained in each of the economically important traits. Body weight remains the most profitable trait in a broiler enterprise; however breeder egg production is equally important as the industry would fail without sufficient day-old broilers. Therefore, it would be beneficial to determine whether current egg production levels could be maintained, or even improved, whilst improvement is made to the growth rate of the progeny. The above statement was found to be possible with the use of index selection. This multiple trait selection strategy proved capable of defying the negative genetic correlation that exists between body weight and egg production by improving egg production to 60 weeks by eight eggs, and body weight at 35 days by 259 grams. Furthermore, in some cases index selection was able to achieve improvements in some traits greater than those attained with single trait selection, whilst simultaneously improving certain negatively correlated traits. Index selection has illustrated its superiority over single trait selection strategies and its relative value to the poultry industry. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2009.

Infection of small ruminants by gastrointestinal nematodes (GIN) is a major health concern because they cause substantial economic losses, especially in the tropics and sub-tropics. For many years, control of GIN has been based upon use of anthelmintics. However, there is now a global challange because mutant GIN individuals can tolerate most of the widely used anthelmintics. Therefore, alternative control measures are needed. The objective of the study was to screen a number of plant species for their anthelmintic effects, and to evaluate selected strains of Bacillus thuringiensis (Berliner) and Clonostachys rosea (Schroers) for activity against sheep GIN. Subsequently, the combined treatments would test a dual control strategy for nematodes by using a combination of plant extracts with biocontrol agents. Ethanol extracts of 25 plant species were screened for their anthelmintic effects against Haemonchus contortus (Rudolphi 1803). Extracts of each plant were used in vitro at various concentrations (10, 20 and 30%) to treat 10 day faecal cultures. Five plants with high efficacies (Ananas comosus L. Merr., Aloe ferox Mill., Allium sativum Linn., Lespedeza cuneata Dum. Cours. and Warburgia salutaris Bertol.f. Chiov) were selected for further investigation, using ethanol, dichloromethane and water extracts at four concentrations (2.5, 5, 10 and 20%). Ethanol was the most effective solvent. Larval counts decreased as a result of increasing extract concentrations. An ethanolic extract of Lespedeza cuneata caused more than 70% mortality at all concentrations. In an in vivo study, the five plants A. comosus, A. ferox, A. sativum, L. cuneata and W. salutaris extracts were compared to a positive Control (Equimax®, a modern anthelmintic based on abamectin and praziquantel). Gender, eggs count (EPG₀) and initial body weights were used in assigning sheep (24 females and 24 males) to six groups. Each group was randomly assigned a treatment. Plant extracts were applied as an oral dose (100 mg kg⁻¹ BW), one dose per week per animal for 42 days (Phase 1). Subsequently, the same sheep were dosed for three consecutive days with the same treatments, keeping them in the same groups (Phase 2). Rectal faecal samples were taken for counting of eggs per gram of faeces (EPG) and L₃ larvae per gram (LPG) in faecal cultures. With application of plant extracts, the EPG count decreased with time (P<0.001), and the impact of the plant extracts increased (P<0.001) with time. Two extracts, from A. comosus and L. cuneata, were the most effective in Phase 1 (58% and 61% reduction of EPG, respectively,), and in Phase 2 (77% and 81% reduction of EPG, respectively). In a study on potential biocontrol agents, two strains of Bacillus thuringiensis (Bt) and one of Clonostachys rosea f. rosea (C. rosea), and compared with a diatomaceous earth (DE) product for their anthelmintic activity in sheep. Bacillus thuringiensis and C. rosea were fed to sheep at a rate of 1g kg⁻¹ BW, and DE was fed at 2% of sheep diet. The biocontrol treatments had no effect on EPG (P>0.05), but reduced GIN larvae per gram (LPG) (P<0.001) in faecal culture. Efficacy varied with time (P<0.001). By Day 7 Bt, C. rosea and DE had caused mortalities of GIN of 75.7, 86.9 and 60.6%, respectively. In addition, the efficacy of feeding 1g kg⁻¹ BW of C. rosea chlamydospores to sheep every day, every second day and every third day was tested. Daily feeding of fungal chlamydospores reduced LPG (a count of 12±1.67 GIN larvae) (P<0.001) more than feeding them the biocontrol agent every second day (39±0.77) or third day (58±1.77). By Day 12, feeding the biocontrol agent to sheep every day, every second day, or every third day caused mortality of GIN larvae of 90, 63 and 49%, respectively. Four dietary levels (treatments) of C. rosea (0.25g (F1), 0.5g (F2), 1g (F3) and control (C) of C. rosea product kg-1 BW) were tested. Treatments were each mixed with a complete diet and fed to sheep once daily for 10 weeks, according to body weights. Increased doses of the biocontrol agent reduced LPG (P<0.001), larval development (LD) (P<0.001), and increased efficacy (P<0.001). On Day 70, F1, F2, F3 and the Control controlled LD by 33.3, 72.3, 89.4 and 2.6%, respectively. Clonostachys rosea was effective in reducing third stage larvae (L₃) on pastures significantly (P<0.001) by Day 63 and Day 70. Ethanolic extracts of A. comosus, A. ferox, A. sativum, L. cuneata and W. salutaris all reduced egg production by GIN parasites of sheep. Feeding sheep cultured chlamydospores of a biocontrol fungus, Clonostachys rosea, reduced counts of nematode larvae in sheep; and 1g C. rosea chlamydospores kg⁻¹ BW daily was enough to reduce nematode infective larvae, therefore reducing the degree of pasture contamination. An initial trial showed that the combination of the two treatments of an A. comosus extract and C. rosea chlamydospores was more effective than either treatment on its own in controlling gastrointestinal nematodes in sheep. A long-term trial is being undertaken currently to confirm this finding. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.

Broiler production is an important animal production enterprise with potential to make high returns. Increasing feed efficiency and early body weight gain has always been a top priority in the broiler industry. The general objective of broiler nutrition is to maximise production performance and profitability . Nutrition is of major importance in raising chicken, and feed is a major input in poultry production systems, accounting for over 60% of total production costs in commercial poultry sector Renkema (1992). The cost of feed is therefore often a constraint especially in developing countries. For instance, Onyenokwe (1994) observed that high cost of feed ingredients in many African countries has caused many poultry farmers to abandon the industry. The continued rise in feed prices is due to competition for some of the ingredients with human e.g. sorghum, wheat and maize. Broiler farmers are therefore forced to use combinations of feed ingredients of low cost to obtain savings and avoid any further loss of profits. It is therefore important to give special attention to feed and feeding since the rate of feed consumption increases rapidly with advancing age of the birds and good nutrition is reflected in the bird's performance and its products. The profitability of a broiler enterprise depends on the efficient conversion of feed to meat. Broilers have the ability to convert the feeds into meat with a high efficiency. For instance Morris and Njuru (1990) reported that broilers have much higher daily rates of protein deposition than layer chicken strains. This implies that fast-growing strains would require greater daily protein intakes than slow-growing ones. In the past, the major criteria for assessing the performance of broilers has been growth rate and feed conversion ratio (FeR). Diet specifications and feeding programmes have been aimed at maximising these two parameters whereby overall flock performance is calculated based on the total weight of chicken produced from total feed deliveries. With the new developments in understanding of nutritional factors affecting broiler growth and carcass composition, it is now possible to apply sophisticated and yet efficient approaches to feeding broilers. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Summary: Swaziland has long had a disparity between the supply and demand of milk. Even at present milk production continues to be less than the market demand. The quantitative contribution of smallholder dairy farmers to local milk production remains unknown because of poor record keeping. This study was aimed at attaining a clear understanding of the dynamics of smallholder dairying in Swaziland, including the identification and understanding of the constraints faced by farmers in dairying, with the hope of devising workable solutions to them. A sample of 118 smallholder dairy farms were covered in this study, with a total herd of 306 lactating cows, comprising mainly of Jerseys and Holstein Friesians, with some cross breeds. There were no significant differences in mean milk yield/cow with respect to farmer gender (P > 0.05) and Agro-ecological zone location (P > 0.05) of the farms. Milking frequency had a significant effect on milk yield, since cattle milked once a day had lower (P < 0.05) milk yields than those milked twice a day. The cattle had extensively long calving intervals i.e. 448 ± 166 days, ranging from 292 to 1082 days. Low milk yield and poor reproductive performance of cattle were found to be mainly due to poor nutrition, breeding practices and stock quality. These are primarily a result of insufficient farmer training and inadequate technical assistance, scarce availability of quality stock, lack of investment resources and market support that includes favourable milk prices for farmers to make money. This performance of the Swazi smallholder dairy herd was then evaluated by comparing it to the performance of a larger, well-managed herd of known pedigree. Lactation records from 252 Jersey cows and 108 Holstein Friesian cows were obtained from Cedara Agricultural Research Institute, covering the periods; July, 2002 to July, 2004 and November, 2002 to April, 2004, respectively. Cows were grouped by parity and calving season and the gamma function proposed by Wood (Y = An(b) e(-cn)) was used to fit standard lactation curves on group data. The curve parameters A and b increased with parity, while that of c and s (persistency of lactation at peak) decreased, producing standard lactation curves save for the Holstein Friesian summer calvers, which produced atypical curves. The R(2) values (goodness of fit) increased with parity. Animal parity and calving season were found to influence the peak and shape of the lactation curves and their parameter estimates. The performance of the Swazi smallholder herd showed a mean deviation of the observed daily milk yield of the Holstein Friesian breed from the expected yield to be - 3.47 (SD 6.052) kg and that of the Jersey breed was - 16.92 (SD 5.473) kg. The mean proportional deviation of observed milk yield from the expected yield for the Holstein Friesian breed was - 0.3 (SD 0.37) and that of the Jersey breed to be - 0.6 (SD 0.19). The proportional milk yield deviation of the Holstein Friesian breed can be explained using the equation Y = O.1322(SE = 0.1293) x - 2.3581 (SE = 0.20639), where x = expected milk yield and Y is the proportional deviation of the observed milk yield deviation from the expected milk yield. With respect to the smallholder Jersey breed, no relationship was found that could explain the proportional milk yield deviation. The smallholder herd was shown to be underperforming, considering the potential for higher milk yields of the two breeds. In the quest to gain a greater understanding of the dynamics of smallholder dairying, the sample of 118 farmers was further analysed using multivariate statistics to categorise them based on their herd sizes, herd structures, management and success perceptions in dairying. The analysis produced three clusters (categories): cluster 1 had the largest herd sizes and poor milk production efficiency; cluster 2 had intermediate herd sizes, the highest number of farmers and more efficient milk production per cow. This cluster, however, had the highest proportion of calf mortalities. Cluster 3 had the smallest herd size, the lowest calf to cow ratio and the second highest calf mortality. Record keeping across all clusters was very poor and the average milk yield per cow was generally low. Most of the farmers do not appreciate the importance of annual calving of their cows as an integral part of the success of their dairy projects and winter feed supplementation is very poor across all the clusters. There remains a great need for the enlightenment of the farmers on the importance of good nutrition, breeding, calf rearing and record keeping in successful dairying. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Feeding of lespedeza to sheep and goats, besides supplying protein, could be a possible alternative remedial control measure against gastro-intestinal parasites in sheep and goats. However, the feeding behaviour of individual animals and their feed intake are likely to influence t its effect on the parasites. This study was conducted to determine the different feeding behaviour of sheep and goats on Sericea lespedeza and its effect on faecal egg count. The first part dealt with behaviour of animals feeding on lespedeza or leucaena within the rangeland while for parasitic response they were fed on lespedeza or veld hay. During feeding behavior, three sheep and three goats averaged 2- 3 years of age were observed for 30 days during the months of March and April 2006. Activities such as browsing, grazing and idling were recorded after every two minutes for every animal while following animals at a distance of five meters. Feed intake was determined by recording the number of bites made by each animal for a period of ten minutes and by estimating the weight of forage eaten. More (P<0.001) browsing time was observed on goats at both lespedeza and leucaena plot than on sheep, with goats consistently spending longer time browsing than sheep on both lespedeza and leucaena than sheep between 7.00 and 14.00h. More of the browsing time of goats was spent on leucaena than on lespedeza. The longest time of grazing by animals was on the lespedeza plot than on leucaena plot, with sheep grazing for a longer (P<0.001) time than goats. The biggest difference in grazing time for sheep at the lespedeza and leucaena occurred during morning hours. Animal type and interaction of feed animal type significantly affected idling time with goats Idling for a longer (P<0.001) time than sheep at both the lespedeza and leucaena plots. Feeding rate (bite/min) for both sheep and goats were similar on both lespedeza and leucaena plots. Intake rates were higher (P<0.01) for both sheep and goats on leucaena than on lespedeza, with sheep having higher (P<0.01) intake rates than goats on both plots. Animals had the fastest bite rate and intake rate during midday (12.00h) and lowest rates at 14.00h. The highest intake rate occurred on leucaena in the morning and afternoon, but lower than lespedeza during midday. For parasites response twelve sheep and twelve goats aged between 3 and 4 years were used in a study that lasted 60 days. Animals were naturally infested by gastro-intestinal parasites. Egg count was done according to McMaster egg count technique (Ministry of Agriculture, Fisheries and Food, 1977) by magnifying parasitic eggs from faecal samples dissolved in saturated sodium chloride. During feacal egg count, the effect of animal on feed intake was highly significant (P<0.001) with sheep consuming more of each kind of feed (lespedeza or hay) than goats. Live weight of animals decreased during the early period of feeding, beyond which it remained stable. Egg count varied significantly (P = 0.015) among periods of sampling, a general trend indicating a decrease from day 0 to day 46 beyond which egg count tended to increase. When regression analysis was done to determine the effect of the previous week’s intake, it was observed that increased intake during the previous week was associated with depression in egg count, the effect attaining significance (P<0.05) for both sheep and goats on hay and for sheep on lespedeza. The results of this study are rather inconclusive about the effect of supplementing small ruminants with Sericea lespedeza hay on gastro-intestinal parasites, owing to variation associated with intake of lespedeza and hay, thus warranting further investigation. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.