Utilisation of indigenous knowledge to control gastrointestinal nematodes in Southern Africa.

Gastrointestinal nematodes (GIN) exacerbate the impact of droughts on the survival of cattle. The inadequacies of the conventional system make it increasingly important to explore indigenous knowledge (IK) to create drought-tolerant and GIN resilient herds. The objective of the study was to assess the indigenous strategies for controlling GIN during droughts. Face-to-face interviews with experts on IK were conducted to give insight into the importance, methods and ranking of GIN control. The experts identified 86 cattle that were used to test their assertions. The control methods used were identifying cattle that were susceptible to high GIN loads using predisposing factors, diagnosis of GIN burdens using faecal appearance, and treatment using phytotherapy. Experts ranked predisposing factors as the most critical control strategy and identified body condition, class, sex, coat colour, pregnancy status and lactation status as predisposing factors to high GIN burdens. Thin, older, dark-coloured cattle, as well as pregnant and lactating cows, were considered susceptible to GIN. However, pregnancy status, coat colour and sex were significantly associated with high GIN burdens. Cows were 2.6 times more likely to have high GIN burdens than bulls. Dark-coloured cattle were 3.5 times more likely to have high GIN burdens than light-coloured ones, and the likelihood of pregnant cows was 4.9 times higher than non-pregnant cows. A dark-coloured pregnant cow was extremely susceptible to high GIN burdens. In conclusion, knowledge of predisposing factors informs selection decisions when purchasing foundation stock. Cattle that are susceptible to high GIN loads are prioritised during droughts or culled where resources are scarce.

Relationship between faecal egg count and health status in Nguni goats reared on semi-arid rangelands.

Gastrointestinal parasitism is a major constraint to goat productivity, particularly in resource-limited production systems. The objective of the study was to determine the relationship between faecal egg count and the health status of different classes of Nguni goats. Body condition score (BCS), packed cell volume (PCV), FAMACHA score, and faecal egg count (FEC) were measured in 120 goats of different classes (weaners, does and bucks) across seasons. The identified gastrointestinal nematodes (GIN) were Strongyloides (30 %), Haemonchus contortus (28 %), Trichostrongylus sp. (23 %), Oesophagostomum sp. (17 %) and Ostertagia (2 %), which showed higher prevalence at the hot-wet season compared to other seasons. An interaction (P<0.05) between class and season on BCS was observed. Lower PCV were observed in weaners (24.6 ± 0.79) in the post-rainy season, whereas does 27.4 ± 0.86 and bucks (29.3±1.03) had the highest PCV in the same season. Higher FAMACHA scores were observed in the hot seasons for all goat classes, while lower in the cool-dry season. Linear relationships between FAMACHA scores and FEC were observed in all seasons. The rate of change in FAMACHA score was higher in the post-rainy season (P<0.01) than in other seasons as FEC increased in weaners and does. Bucks had a higher rate of change in FAMACHA in the hot-wet season (P<0.0001) as FEC increased. The rate of BCS decline was higher in the post-rainy season in weaners and does (P<0.01) and bucks (P<0.05) than in other seasons. The decline in PCV was faster during the wet than in the dry seasons. It can be concluded that class and season affected BCS, FAMACHA, and PCV. A linear relationship between FEC and FAMACHA score suggests that FAMACHA could be a good indicator of GIN burden.

Factors influencing the integration of indigenous and conventional knowledge of water security for livestock.

Farmers have developed indigenous knowledge (IK) on predictive and adaptation strategies to sustain water security. The objective of the study was to determine factors that influence the integration of IK and conventional knowledge (CK) to ensure water security for livestock. Focus group discussions and semi-structured interviews were used to gather data. Farmers in Musina and uMhlabuyalingana use IK indicators to predict rain for water security. Farmers in uMhlabuyalingana predicted rain using wind movement more than their counterparts in Musina (P < 0.05). Taboos were used (P > 0.05) in both Musina and uMhlabuyalingana to ensure water security. Cultural prohibitions were used more in uMhlabuyalingana to cope with water shortages than in Musina (P < 0.05). Boreholes, home taps and municipal water were not properly maintained (P > 0.05). Socio-economic factors had greater influence on the integration of IK and CK. Males were 2.24 times likely to support integration of IK and CK compared to women. Adults were 7.1 times likely to support integration of IK and CK compared to those that were younger. Farmers were open to the integration of conventional and indigenous knowledge to ensure water security. Promoting the integration of IK and CK enables stakeholders to gain access to valuable information which can, in turn, promote sustainable community development.

Growth performance of South African Windsnyer pigs to the dietary inclusion of Amarula oil cake.

Dietary inclusion of Amarula oil cake (AOC) in pig diets can ease pressure of relying on non-native feed sources and benefit the swine industry. The study was conducted to determine the growth performance of Windsnyer pigs fed increasing levels of AOC. Twenty-five clinically growing male boars with an initial body weight of 19.92 ± 8.74 kg were used in the study that lasted 6 weeks. All pigs were allocated to diets in a completely randomised design. Five experimental diets were formulated to contain 0, 50, 100, 150 and 200 g/kg DM of AOC. Average daily feed intake (ADFI), average daily gain (ADG), feed conversion ratio (FCR), scaled average daily feed intake (SADFI), scaled average daily gain (SADG) and body weight (BW) were calculated weekly. The diet affected ADFI, ADG, FCR and SADG (P < 0.05). Scaled average daily feed intake was not affected by the diet (P > 0.05). There was a significant interaction between AOC inclusion and weeks of feeding on ADFI, ADG and FCR (P < 0.05). Age of pigs decreased FCR quadratically (P < 0.001). A quadratic relationship between ADFI and increasing levels of AOC was observed (P < 0.05). Average daily gain, FCR and SADG decreased linearly with increasing AOC levels (P < 0.05). Using the broken stick analyses, the maximum inclusion of AOC was 102.17 g/kg DM. Amarula oil cake can be incorporated in diets of Windsnyer pigs up to 100 g/kg DM without constraining growth performance.

Runs of homozygosity analysis of South African sheep breeds from various production systems investigated using OvineSNP50k data.

BACKGROUND: Population history, production system and within-breed selection pressure impacts the genome architecture resulting in reduced genetic diversity and increased frequency of runs of homozygosity islands. This study tested the hypothesis that production systems geared towards specific traits of importance or natural or artificial selection pressures influenced the occurrence and distribution of runs of homozygosity (ROH) in the South African sheep population. The Illumina OvineSNP50 BeadChip was used to genotype 400 sheep belonging to 13 breeds from South Africa representing mutton, pelt and mutton and wool dual-purpose breeds, including indigenous non-descript breeds that are reared by smallholder farmers. To get more insight into the autozygosity and distribution of ROH islands of South African breeds relative to global populations, 623 genotypes of sheep from worldwide populations were included in the analysis. Runs of homozygosity were computed at cut-offs of 1-6 Mb, 6-12 Mb, 12-24 Mb, 24-48 Mb and > 48 Mb, using the R package detectRUNS. The Golden Helix SVS program was used to investigate the ROH islands. RESULTS: A total of 121,399 ROH with mean number of ROH per animal per breed ranging from 800 (African White Dorper) to 15,097 (Australian Poll Dorset) were obtained. Analysis of the distribution of ROH according to their size showed that, for all breeds, the majority of the detected ROH were in the short (1-6 Mb) category (88.2%). Most animals had no ROH > 48 Mb. Of the South African breeds, the Nguni and the Blackhead Persian displayed high ROH based inbreeding (FROH) of 0.31 ± 0.05 and 0.31 ± 0.04, respectively. Highest incidence of common runs per SNP across breeds was observed on chromosome 10 with over 250 incidences of common ROHs. Mean proportion of SNPs per breed per ROH island ranged from 0.02 ± 0.15 (island ROH224 on chromosome 23) to 0.13 ± 0.29 (island ROH175 on chromosome 15). Seventeen (17) of the islands had SNPs observed in single populations (unique ROH islands). The MacArthur Merino (MCM) population had five unique ROH islands followed by Blackhead Persian and Nguni with three each whilst the South African Mutton Merino, SA Merino, White Vital Swakara, Karakul, Dorset Horn and Chinese Merino each had one unique ROH island. Genes within ROH islands were associated with predominantly metabolic and immune response traits and predomestic selection for traits such as presence or absence of horns. CONCLUSIONS: Overall, the frequency and patterns of distribution of ROH observed in this study corresponds to the breed history and implied selection pressures exposed to the sheep populations under study.

In vitro efficacy of plant extracts against gastrointestinal nematodes in goats.

Farmers use plant extracts as a potential source of anthelmintic compounds against gastrointestinal nematodes in goats. The objective of the study was to investigate the in vitro anthelmintic activity of aqueous (cold and boiled) and methanolic extracts of Cissus quadrangularis Linn., Aloe marlothii A. Berger, Albizia anthelmintica Brongn., Cissus rotundifolia (Forssk.) Vahl., Sclerocarya birrea (A. Rich.) Hochst, and Vachellia xanthophloea (Benth.) P.J.H. Hurter plants against gastrointestinal nematodes (GIN). Plants were used in two forms: dry and fresh. Decoction (boiled water), infusion (cold water), and methanolic extracts at concentrations of 8, 16, 24, 32, and 40% v/v were tested in vitro on mortality of L3 nematodes. Linear relationships were observed between larvae mortality and extract concentration of the boiled fresh form of C. rotundifolia (P < 0.01), fresh form of cold-water of A. marlothii (P < 0.05), fresh form of cold-water and methanolic C. quadrangularis (P < 0.01), dry form of cold-water and methanolic S. birrea (P < 0.0001), and dry form of cold-water and fresh form of methanolic V. xanthophloea (P < 0.05). Quadratic relationships were observed between larvae mortality and extract concentration of the fresh form of methanolic C. rotundifolia (P < 0.05), fresh form of methanolic A. anthelmintica (P < 0.01), the fresh form of methanol and the dry form of boiled A. marlothii (P < 0.001), fresh form of methanolic (P < 0.05) and dry form of boiled S. birrea (P < 0.01), fresh form of cold and boiled water of V. xanthophloea (P < 0.0001), and dry form of boiled water and methanolic V. xanthophloea (P < 0.05). The crude plant extracts of C. quadrangularis, A. marlothii, A. anthelmintica, C. rotundifolia, S. birrea, and V. xanthophloea could be considered as an integrated approach to achieve sustainable nematode control in goats.

Nitrogen balance in slow-growing Windsnyer pigs fed on incremental levels of amarula (Sclerocarya birrea subsp. caffra) nut cake.

Feeding-derived amarula cake to growing pigs can overcome a narrow range of ingredients challenges and improve productivity. The objective of the current study was to determine the response in nitrogen (N) balance in slow-growing pigs fed on incremental levels of amarula nut cake (ANC). Thirty clinically healthy male growing Windsnyer (30.7 kg ± 6.57) (mean ± standard deviation) were individually assigned to separate pens in a completely randomized design, with six pigs per dietary treatment. Iso-energetic experimental diets were formulated to contain 0, 50, 100, 150, and 200 g/kg dry matter (DM) of ANC using the summit and dilution technique. Pigs were given 10 days of dietary adaptation and a collection period of 5 consecutive days after 31 days of feeding. Nitrogen intake increased linearly with incremental levels of ANC (P < 0.01). As ANC inclusion increased, the nitrogen (N) absorption, apparent N digestibility, and N retention in pigs increased until it reached a maximum, then started to decrease (P < 0.05). Nitrogen utilization increased at the rate of 0.63 g for each 1 g increase in ANC (P < 0.01). There was a linear decrease (P < 0.01) in total nitrogen excretion through urine and faeces with ANC inclusion. Urinary pH levels decreased quadratically in response to graded levels of ANC (P < 0.01). The relationship between urinary pH and ANC inclusion was Y = 0.0115x2 - 0.3491x + 4.872 (P < 0.01). The nitrogen balance responses were due to ANC inclusion in diets that were balanced for limiting amino acids. It can be concluded that ANC reduces N excretion, potentially minimizing ammonia volatilization, which makes it an alternative protein source for slow-growing pigs.

The genomic architecture of South African mutton, pelt, dual-purpose and nondescript sheep breeds relative to global sheep populations.

South Africa has a diverse array of phenotypically distinct and locally adapted sheep breeds that have been developed for different production systems ranging from mutton to wool and pelt, and some dual-purpose and nondescript breeds kept by smallholder farmers. This study investigated genetic diversity, population genetic structure and divergence between South African sheep breeds in order to gain an insight into breed history and genomic architecture aligned to breeding goals and production systems. The Illumina OvineSNP50 BeadChip was used to genotype 400 sheep belonging to 14 breeds representing mutton, pelt and mutton and wool dual-purpose breeds. Nguni sheep were included as a representative of indigenous nondescript breeds that are reared by smallholder farmers. Seeking a clearer understanding of the genetic diversity of South African breeds relative to global populations, 623 genotypes of sheep from worldwide populations were included in the analysis. These sheep breeds included six African, two Asian and eight European breeds. Across breeds, genetic diversity ranged from observed heterozygosity (H0 ) = 0.26 ± 0.02 in Namaqua Afrikaner to H0  = 0.38 ± 0.01 in Dohne Merino. The overall mean H0 was 0.35 ± 0.04. The African and Asian populations were the most inbred populations with FIS ranging from 0.17 ± 0.05 in Grey Swakara and Ronderib Afrikaner sheep to 0.34 ± 0.07 in the Namaqua Afrikaner. The South African Dohne Merino (FIS  = 0.03 ± 0.01), SA Merino (FIS  = 0.05 ± 0.04) and Afrino (FIS  = 0.09 ± 0.02) and other global Merino-derived breeds were the least inbred. The first principal component explained 27.7% of the variation and separated the fat- and rump-tailed sheep (i.e. Swakara, Nguni, Blackhead Persian, Ethiopian Menzi, Meatmaster) from the Merino and Merino-derived breeds and the Dorset Horn. The second principal component separated the Merino and Merino-derived breeds from the English breed of Dorset Horn. Overall, South African indigenous breeds clustered together with indigenous breeds from other African and Asian countries. The optimal admixture cluster (K = 20) revealed various sources of within- and amongst-breed genomic variation associated with production purpose, adaptation and history of the breeds. The Blackhead Persian, Nguni and Namaqua Afrikaner breeds differed significantly from other breeds, particularly with the South African Mutton Merino and Dorset Horn. Breed-differentiating SNPs were observed within genomic regions associated with growth, adaptation and reproduction. Genes such as RAB44, associated with growth and meat/carcass traits, differentiated the Blackhead Persian from the Dorset Horn and South African Mutton Merino. The MAP2 and HRAS genes, which are associated with immune traits involving Toll-like receptors and Chemokine signalling pathways, differentiated the Nguni from the Dorset Horn. The current results give insight into the current status of the sheep genetic resources of South Africa relative to the global sheep population, highlighting both genetic similarities as well as divergence associated with production systems, geographical distribution and local adaptation.

Effect of vegetation density on survival of South African free-ranging indigenous chicken broods.

The survival of juveniles from hatching until recruitment is a critical determinant of indigenous chicken population growth under extensive free-range production systems. A longitudinal study was conducted to investigate the impact of vegetation cover on survival of indigenous chicken broods in Msinga, South Africa. Survival records of 281 chicks hatched in sparsely vegetated (SV) communal lands and 233 hatched chicks in densely vegetated (DV) resettlement areas were collected from hatch until 12 weeks of age. Data on probable cause of death of individual chicks was collected using a structured checklist. Kaplan-Meir survival distributions and log rank tests were used to estimate the survival functions of broods between vegetation cover types. Logistic regression analysis was used to determine the association between management factors and mortality risk in SV and DV. Chick survival from hatching to 12 weeks was higher in SV (55 ± 3.14%) than DV (41 ± 4.19%) (P < 0.05). Mean chick survival time did not differ between SV (56 ± 3.30 days) and DV (49 ± 3.23 days) (P > 0.05). Aerial predators were the major cause of chick mortality (over 60%) followed by terrestrial predators (30%) in both vegetation cover types. The odds of mortality were higher in DV compared to SV (P < 0.05). It was concluded that increasing vegetation cover decreases survival of scavenging chicks between hatching and end of brooding at 12 weeks of age, and therefore brood management actions should ensure adequate protection of free-ranging chicken broods in densely vegetated rearing habitats.

Utilisation of indigenous knowledge to control ticks in goats: a case of KwaZulu-Natal Province, South Africa.

Local indigenous knowledge (IK) informs decision-making about fundamental aspects of life. The inclusion of indigenous knowledge is increasingly becoming a topical subject to enhance livestock veterinary care. The objective of the current study was to explore the extent of utilisation of indigenous knowledge to control ticks in goats. There was an association (P < 0.05) between the use of IK and gender, with males using IK (76.58%) more than females. The association between age distribution and IK use was (P < 0.05); however, farmers above the age of 50 years were using IK more than all group ages. Farmers ranked the purposes of using IK differently (P < 0.05). Ectoparasites were ranked as the most important constraint limiting goat productivity. Ticks were ranked as the most important external parasites. Amblyomma tick species were ranked as the most important amongst the tick species, followed by Rhipicephalus evertsi evertsi ticks. A significant population of farmers (80.7%) are dependent on the use of tick sprays, whereas others used injections (3.3%). Cissus quadrangularis L. (Inhlashwana) was singled out as the most used ethno-veterinary plant to control ticks with a frequency of (64%), followed by Gomphocarpus physocarpus E. Mey (Uphehlacwathi) (55.9%). The probability of keeping goats in wet rangelands (P < 0.05) was 3.04 times more likely to influence the extent of IK use compared to their contemporaries in the dry rangeland. Male farmers keeping goats (P < 0.01) were 2.95 more likely to influence the extent of use of IK than females. The type of rangeland, gender, age, residing on farm and also having the herbalist in the locality were the most common factors that influenced the extent of IK utilisation.

Health status of non-descript goats travelling long distances to water source.

The objective of the study was to determine the influence of distance to water source on health status of non-descript weaners and does. The goats were situated at 0.25, 0.75, 1.25, 1.75, 2.25, 2.75 and 3.25 km from the Pongola river. Body condition score (BCS) declined faster in male weaners than female weaners as the distance to water source increased (P < 0.001). The rate of decline in BCS was similar between does and female weaners as the distance to water source increased (P > 0.05). Rectal temperature (RT) of all goat classes increased with an increase in distance to water source (P < 0.05). Rate of change in RT was higher in female weaners than male weaners and does as the distance to water source increased (P < 0.01). The increase in FAMACHA scores was higher in male weaners than does and female weaners as the distance to water source increased (P < 0.05). Does had the smallest drop in packed cell volume (PCV) than female and male weaners as the distance to water source increased (P > 0.05). All goat classes were severely affected by the distance to water source; however, the effects were more adverse in male weaners than in female weaners and does. Body condition score and PCV declined, whereas RT and FAMACHA increased with an increase in distance travelled by goats to the water source. It can be concluded that both male and female weaners were more susceptible to increasing distance to water source.

Voluntary feed intake and growth performance of slow-growing pigs fed on increasing levels of ensiled potato hash meal.

The objective of the study was to determine voluntary feed intake and growth performance of Windsnyer pigs fed on increasing levels of potato hash silage meal. Thirty-six growing Windsnyer pigs (19 kg ± 5.59) (mean ± standard deviation (SD)) were individually and randomly assigned to six experimental diets containing 0, 80, 160, 240, 320 and 400 g/kg DM of potato hash silage. Diets containing the potato hash silage were formulated using diet dilution method from 0 g/kg and 400 g/kg. Six pigs were fed on each diet ad libitum for 6 weeks. Average daily feed intake (ADFI), average daily gain (ADG), gain to feed (G/F) ratio, scaled feed intake (SFI) and scaled average daily gain (SADG) were measured weekly. Increasing levels of potato hash silage caused a decrease (P < 0.05) in ADG, G/F ratio and SADG. The ADFI interacted significantly (P < 0.05) with the inclusion level of potato hash silage and week of feeding. Pigs fed on 240 g/kg potato hash silage had greater ADFI in the second, third and fourth week of feeding. There was a quadratic increase (P < 0.05) in ADFI. There was a linear decrease (P < 0.05) in ADG and G/F ratio and SADG as the potato hash silage level increased. Using piecewise regression, potato hash silage can be included up to 240 g/kg DM in Windsnyer pigs without undermining growth performance.

Physical and chemical properties of meat from scavenging chickens and helmeted guinea fowls in response to age and sex.

1. The effects of age and sex on body weight, carcass traits, physical and chemical properties of breast muscle from chickens and helmeted guinea fowls managed under village free-range conditions were assessed in random samples of 48 guinea fowls and 48 chickens obtained from local markets. 2. Guinea fowls had higher body weight, hot carcass weight, cold dressed weight and breast weight than chickens. 3. Guinea fowls had more dry matter, protein and less fat than chickens. Ash content did not differ between guinea fowls and chickens. Protein and fat increased, whereas dry matter and ash decreased with age (P < 0.05) 4. Chicken meat was lighter, less red and more yellow than guinea fowl meat. Cooking loss was higher in guinea fowls, male and grower birds than chickens, females and adult birds, respectively. Shear force was affected by age, as mature birds had a higher value than growers. 5. Guinea fowl carcasses contained more meat that was leaner, higher in protein and redder compared with chicken meat. As age increased the meat increased in protein and fat content and shear force, whereas colour became darker, redder and yellower.

Efficacy of adsorbents (bentonite and diatomaceous earth) and turmeric (Curcuma longa) in alleviating the toxic effects of aflatoxin in chicks.

A study was conducted to determine the efficacy of bentonite clay (BC), diatomaceous earth (DE) and turmeric powder (TUM) in alleviating the toxic effects of aflatoxin B1 (AFB1). A total of 250 Ross-308 d-old male broiler chicks were assigned to 10 dietary treatments (5 replicates of 5 chicks) from hatch to d 21. Dietary treatments were: basal diet; basal diet plus AFB1 (2 mg) or BC (0.75%), or DE (0.75%), or TUM (200 mg/kg curcuminoids) and different combinations of AFB1, BC, DE and TUM. Feed intake (FI), body weight gain (BWG) and feed gain (FG) of the birds fed on BC or DE separately were not different from control birds. Birds fed on TUM only had similar FI and FG but lower BWG than control chicks. Aflatoxin B1 reduced FI, BWG and serum concentrations of glucose, albumin, total protein calcium, but increased FG and relative liver and kidney weights. Chicks fed on the combination of AFB1 and BC had similar FI and FG to control chicks. Chicks fed on the combination of DE and AFB1 had lower FI (23.1%) and BWG (28.6%) compared with control chicks. Chicks fed on the combination of TUM and AFB1 also had decreased FI (26.2 %) and BWG (31%) compared with control chicks. Chicks fed on the combination of AFB1, BC and TUM consumed significantly higher amounts of feed compared with chicks fed on only AF, but gained less when compared with control diet chicks. Chicks fed on the combination of AFB1, DE and TUM diet had poorer growth performance than those fed on AFB1 alone. None of the combination diets reduced the severity of liver lesions.

Potential of Using Maize Cobs in Pig Diets - A Review.

The quest to broaden the narrow range of feed ingredients available to pig producers has prompted research on the use of low cost, unconventional feedstuffs, which are typically fibrous and abundant. Maize cobs, a by-product of a major cereal grown worldwide, have potential to be used as a pig feed ingredient. Presently, maize cobs are either dumped or burnt for fuel. The major challenge in using maize cobs in pig diets is their lignocellulosic nature (45% to 55% cellulose, 25% to 35% hemicellulose, and 20% to 30% lignin) which is resistant to pigs' digestive enzymes. The high fiber in maize cobs (930 g neutral detergent fiber/kg dry matter [DM]; 573 g acid detergent fiber/kg DM) increases rate of passage and sequestration of nutrients in the fiber reducing their digestion. However, grinding, heating and fermentation can modify the structure of the fibrous components in the maize cobs and improve their utilization. Pigs can also extract up to 25% of energy maintenance requirements from fermentation products. In addition, dietary fiber improves pig intestinal health by promoting the growth of lactic acid bacteria, which suppress proliferation of pathogenic bacteria in the intestines. This paper reviews maize cob composition and the effect on digestibility of nutrients, intestinal microflora and growth performance and proposes the use of ensiling using exogenous enzymes to enhance utilization in diets of pigs.

Physicochemical properties of breast meat from water-stressed naked-neck and Ovambo chickens.

1. Differences in growth performance, physicochemical properties and fatty acid composition of breast muscle from water-stressed 16-week-old naked-neck (NNK) and Ovambo (OVB) chickens were investigated. 2. OVB chickens had superior (P < 0.05) slaughter weights at 16 weeks of age, average daily gain (ADG) and average daily water intake (ADWI) than NNK chickens. Body weights of birds at 16 weeks of age, ADG, average daily feed intake (ADFI), ADWI and water to feed ratio (WFR) declined progressively with increasing severity of water restriction while the opposite was observed for feed conversion ratio (FCR) values. NNK chickens had better FCR at the 40% of ad libitum water intake than OVB chickens. 3. Meat from NNK chickens had higher redness (a*) values at the 40% of ad libitum water intake but lower lightness (L*) and yellowness (b*) values at 70% of ad libitum and ad libitum water intakes compared with OVB chickens. 4. There was no interaction between strain and water intake on most fatty acids, except for the proportion of elaidic acid (C18:1t9) higher in meat from NNK compared with OVB chickens given water at 40% of ad libitum. Water restriction to 40% of ad libitum water intake had a positive influence on the proportions of linoleic acid (C18:2n-6), arachidonic acid (C20:4n-6), adrenic acid (C22:4n-6), docosahexaenoic acid (C22:6n-3), total polyunsaturated fatty acid (PUFA), total omega-3 PUFA and total omega-6 PUFA proportions, but resulted in lower proportions of total monounsaturated fatty acids (MUFAs) compared with 70% of ad libitum and ad libitum water intakes. 5. It was concluded that cooking loss, meat redness values, omega-3 and omega-6 PUFA proportions and n-6/n-3 ratio of NNK chickens improved with increasing severity of water restriction compared with OVB chickens.

Effects of water restriction on the growth performance, carcass characteristics and organ weights of naked neck and ovambo chickens of southern Africa.

In semi-arid areas of Southern Africa, dehydration can compromise the performance and welfare of local chickens, particularly during the growing period when confinement is curtailed and birds are left to scavenge for feed and water. The effect of water restriction on the growth performance was compared in Naked Neck (NNK) and Ovambo (OVB) chickens that are predominant in Southern Africa. A total of 54 eight-wk-old pullets each of NNK and OVB chickens with an initial average weight of 641±10 g/bird were randomly assigned to three water intake treatments, each having six birds for 8 wk. The water restriction treatments were ad libitum, 70% of ad libitum and 40% of ad libitum intake. Nine experimental pens with a floor space of 3.3 m(2) per strain were used. The pens were housed in an open-sided house with cement floor deep littered with a 20 cm layer of untreated wood shavings. Feed was provided ad libitum. Average daily water intake (ADWI), BW at 16 weeks of age (FBW), ADG, ADFI, feed conversion ratio (FCR) and water to feed ratios (WFR) were determined. Ovambo chickens had superior (p<0.05) FBW, ADG and ADWI than NNK chickens. Body weight of birds at 16 weeks of age, ADG, ADFI, ADWI, and WFR declined progressively (p<0.05) with increasing severity of water restriction while FCR values increased (p<0.05) as the severity of water restriction increased. Naked Neck chickens had better FCR at the 40% of ad libitum water intake level than Ovambo chickens. The dressing percentage per bird was higher in water restricted birds than those on ad libitum water consumption, irrespective of strain. Heart weight was significantly lower in birds on 40% of ad libitum water intake than those on ad libitum and 70% of ad libitum water intake, respectively. In conclusion, NNK chickens performed better than OVB chickens under conditions of water restriction and would be ideal to raise for meat and egg production in locations where water shortages are a major challenge.

Growth performance and behaviour in grouped pigs fed fibrous diet.

The objective of the study was to investigate the effect of feeding fibrous diets on growth performance and occurrence of aggressive behaviours in growing pigs. Sixty healthy castrated pigs (initial body weight: 46.7±4.35 kg) were used. A basal diet was diluted with maize cobs to two levels (0 and 160 g/kg dry matter). Behavioural activities were observed using video cameras for three weeks, 8 h/d starting at 0800 h. Pigs subjected to control diet gained more weight compared to pigs receiving fibrous diet in week 1 (0.47 vs 0.15 kg, respectively) and 2 (1.37 vs 1.04, respectively) (p<0.05). Average daily gain was not affected by treatment diet in the third week. Pigs on high fibrous spent more time eating, lying down, standing, walking and fighting (p<0.05) compared to pigs on control diet. Time spent eating increased as the weeks progressed whilst time spent lying down decreased. Time of day had an effect on time spent on different behavioural activities exhibited by all pigs on different treatment diet (p<0.05). Inactivity was greatest in 5th (1200 to 1300 h) hour of the day for all the pigs on different dietary treatments. Skin lesions appeared the most on neck and shoulder region followed by chest, stomach and hind leg region, and finally head region (p<0.05). Pigs on high fibre diet had more skin lesions in all body regions compared to pigs on control diet (p<0.05). It can be concluded that the high fibrous diet with maize cobs did not affect growth performance and also did not reduce aggressive behaviours. Aggressive behaviours emanated out of frustration when queuing on the feeder. The findings of this study suggest that maize cobs can be included at a level of 160 g/kg in diets of pigs. However, to reduce the level of aggression more feeding space should be provided.

Prediction of scaled feed intake in weaner pigs using physico-chemical properties of fibrous feeds.

The objective of the present study was to predict scaled feed intake (SFI) using the physico-chemical measurements of feed bulk, such that gut capacity can be estimated in weaner pigs. A basal feed with 13·7 MJ digestible energy and 180 g crude protein per kg DM was diluted to six inclusion levels (0, 80, 160, 240, 320 and 400 g/kg DM) using lucerne hay, maize cob, maize stover, sawdust, sunflower husks or grass hay (veld grass). A total of 124 pigs weighing 18·1 (SD 1·37) kg body weight were used. Water-holding capacity (WHC; g water/g DM), bulk density (g DM/ml), neutral-detergent fibre (NDF) and acid-detergent fibre (ADF) influenced the SFI. The quadratic relationship between SFI and WHC was SFI = 19·1 (SEM 3·49)+10·04 (SEM 1·61) WHC-1·11 (SEM 0·17) WHC² (P<0·01). SFI was also related (P<0·01) to NDF and ADF by quadratic functions SFI = 24·3 (SEM 3·55)+0·12 (SEM 0·229) NDF - 0·00 012 (SEM 0·000036) NDF² and SFI = 30·2 (SEM 1·95)+0·112 (SEM 0·0232) ADF-0·000343 (SEM 0·0000612) ADF², respectively. Using broken-stick analyses, the gut capacity was attained when WHC = 4·53 (SEM 1·25) g water/g DM, NDF = 367 (SEM 29) g/kg DM and ADF = 138 (SEM 77) g/kg DM. In conclusion, although threshold values for each were different, WHC, NDF and ADF contents of bulk feeds provide relationships with SFI that can be used to predict gut capacity in weaner pigs.

Selection signature analysis and genome-wide divergence of South African Merino breeds from their founders.

Merino sheep are a breed of choice across the world, popularly kept for their wool and mutton value. They are often reared as a pure breed or used in crossbreeding and are a common component in synthetic breed development. This study evaluated genetic diversity, population structure, and breed divergence in 279 animals of Merino and Merino-based sheep breeds in South Africa using the Illumina Ovine SNP 50K BeadChip. The sheep breeds analysed included the three Merino-derived breeds of Dohne Merino (n = 50); Meatmaster (n = 47); and Afrino (n = 52) and five presumed ancestral populations of Merinos (Merino (n = 46); South African Merino (n = 10); and South African Mutton Merino (n = 8)); and the non-Merino founding breeds of Damara (n = 20); Ronderib Afrikaner (n = 17); and Nguni (n = 29). Highest genetic diversity values were observed in the Dohne Merino (DM), with H o = 0.39 ± 0.01, followed by the Meatmaster and South African Merino (SAM), with H o = 0.37 ± 0.03. The level of inbreeding ranged from 0.0 ± 0.02 (DM) to 0.27 ± 0.05 (Nguni). Analysis of molecular variance (AMOVA) showed high within-population variance (>80%) across all population categories. The first principal component (PC1) separated the Merino, South African Mutton Merino (SAMM), DM, and Afrino (AFR) from the Meatmaster, Damara, Nguni, and Ronderib Afrikaner (RDA). PC2 aligned each Merino-derived breed with its presumed ancestors and separated the SAMM from the Merino and SAM. The iHS analysis yielded selection sweeps across the AFR (12 sweeps), Meatmaster (four sweeps), and DM (29 sweeps). Hair/wool trait genes such as FGF12; metabolic genes of ICA1, NXPH1, and GPR171; and immune response genes of IL22, IL26, IFNAR1, and IL10RB were reported. Other genes include HMGA, which was observed as selection signatures in other populations; WNT5A, important in the development of the skeleton and mammary glands; ANTXR2, associated with adaptation to variation in climatic conditions; and BMP2, which has been reported as strongly selected in both fat-tailed and thin-tailed sheep. The DM vs. SAMM shared all six sweep regions on chromosomes 1, 10, and 11 with AFR vs. SAMM. Genes such as FGF12 on OAR 1:191.3-194.7 Mb and MAP2K4 on OAR 11:28.6-31.3 Mb were observed. The selection sweep on chromosome 10 region 28.6-30.3 Mb harbouring the RXFP2 for polledness was shared between the DM vs. Merino, the Meatmaster vs. Merino, and the Meatmaster vs. Nguni. The DM vs. Merino and the Meatmaster vs. Merino also shared an Rsb-based selection sweep on chromosome 1 region 268.5-269.9 Mb associated with the Calpain gene, CAPN7. The study demonstrated some genetic similarities between the Merino and Merino-derived breeds emanating from common founding populations and some divergence driven by breed-specific selection goals. Overall, information regarding the evolution of these composite breeds from their founding population will guide future breed improvement programs and management and conservation efforts.