South African Journal of Animal Science

The effect of Ulva lactuca on in vitro ruminal gas production kinetics

S. Nell — 2024-12-11

The aim of this study was to determine whether the inclusion of a marine algae found in South African waters, Ulva lactuca, can reduce total gas and methane production in vitro when it replaces lucerne hay in a mixed sheep feed at incremental levels. Four treatments were prepared and incubated using bovine rumen fluid as inoculum: (1) 0 g U. lactuca kg^-1 feed dry matter (DM) (0U), (2) 25 g U. lactuca kg^-1 feed DM (25U), (3) 50 g U. lactuca kg^-1 feed DM (50U), and (4) 100 g U. lactuca kg^-1 feed DM (100 U). Total gas and CO₂ production was determined with the aid of an automated system and methane production was estimated by difference. Cumulative gas production data were fitted to a non-linear model (Y = b(1- exp-c^(t-L))) to estimate values for total gas production (b, mL), rate of gas production (c, mL/h), and a discrete lag time (L, hours). The extent of total gas production was lower for 100U than for 25U, but neither differed from 0U or 50 U. The lag time observed was lower for 50U than 0U, but neither differed from 25U or 100U. No differences were found for the rate of gas production. No differences for any gas production values were observed between treatments. The ratio between methane and total gas production was highest for 100U, which differed from 25U, but not from 0U or 50U. The higher methane ratio observed in the 100U treatment may be attributed to the lower total gas production in this treatment due to the lower fermentability of U. lactuca compared to lucerne.

Assessing parallel testing to improve detection of bovine tuberculosis at a slaughterhouse in Lahore, Pakistan

Rubab Maqsood — 2024-12-11

The current study was designed to evaluate the reliability of the interferon-gamma release assay (IGRA) as a screening test compared to intensive post-mortem inspection using agreement analyses. This study also aimed to determine the prevalence and risk factors of bovine tuberculosis (bTB) among bovines presented for slaughter in the largest abattoir in Lahore, Pakistan. After antimortem inspection, a total of 102 animals were randomly selected for sample and data collection. Selected animals were slaughtered and a thorough post-mortem examination was done for all carcasses to find TB-like lesions. Blood samples were processed by IGRA. Prevalence estimates were generated and Cohen’s Kappa test was done for agreement analyses to compare the reliability of the two tests for bTB diagnosis. A substantial agreement (κ = 0.79) was estimated between the IGRA and intensive post-mortem inspection. The apparent prevalence was computed as 5.88% (95% CI; 2.59–11.97) and the true prevalence was estimated as 3.92% (95% CI; 1.35–9.47). A parallel testing strategy with IGRA and intensive post-mortem inspection is a useful approach for screening bTB.

Vaccination strategies to curb environmental spread of Porcine Circovirus 2

D.F. Silva — 2024-12-11

Integrated farming is an established agricultural practice aimed at increasing productivity per unit area by utilizing animal manure. However, there has been a growing concern regarding swine manure's potential as a disseminator of pathogens in the environment. Among these pathogens is Porcine Circovirus 2 (PCV2), which can persist in the environment for extended periods. The objective of this study is to demonstrate the impact of introducing two PCV2 vaccination protocols on PCV2 load in faecal samples and the surrounding environment. To achieve this, fifty-seven pigs aged 21 d were divided into three groups (A, B, and Control group) and received intramuscular injections of two different PCV2 vaccines as per the manufacturer's instructions. Faecal and environmental samples were collected using polyester swabs and tested for PCV2 using SYBR green quantitative real-time PCR (qPCR). The introduction of vaccination in a PCV2-positive herd led to a reduction in viral load in both faecal samples and the surrounding environment.

Bacillus-based probiotics on broiler chicken performance under coccidiosis and Clostridium perfringens challenge

Rafaela Berto — 2024-12-11

The study analyzed the impacts of two probiotics (Ecobiol® and GutCare®) on growth performance, carcass and cut yields, intestinal morphometry and lesion score, biochemical parameters, and short-chain fatty acid concentration in chickens using a challenge model combining coccidiosis vaccine and Clostridium perfringens. A total of 880 one-day-old male broilers (Cobb 500) were randomly assigned to four treatments with 10 replicates and 22 birds per experimental unit (EU). The treatments consisted of: PC: positive control with the inclusion of 80 g ton^-1 of Enramax® (8% enramycin) until 35 d of age; NC: negative control without the inclusion of growth-promoting probiotic; BA: NC with the inclusion of 1000 g ton^-1 of Ecobiol® (Bacillus amyloliquefaciens - CECT 5940); BS: NC with the inclusion of 500 g ton^-1 of GutCare® (Bacillus subtilis - DSM 32315). Diets used maize–soybean meal in a threephase plan. Broiler chickens on the BA and BS diets had higher feed consumption, body weight gain, and improved feed conversion efficiency at 28 and 42 d when compared to the birds in the negative control. Broiler chickens fed PC, BA, and BS diets had a higher villus height and absorption area in the jejunum at 28 d, compared to the birds in the negative control. There was more butyric acid production by the intestinal microbiota at 28 d of age in broilers on the BA diet. Supplementing with 1000 g/ton of BA and 500 g/ton of BS effectively substituted the 8% enramycin antibiotic, enhancing broiler growth during an induced intestinal challenge.

Broiler performance on maize (Zea mays)–cowpea (Vigna unguiculata) diets fortified with black soldier fly (Hermetia illucens) larvae meal

T.T. Muleya — 2024-12-11

Effects of incorporating full-fat Black Soldier fly (Hermetia illucens) larvae meal (BSFLM) in 4-d sprouted cowpea-based grower and finisher broiler diets were evaluated in broilers. Chicks were raised in an open deep litter facility; 360 Ross 308 chicks started (0–21 days) on a commercial starter diet. In week two, the chicks were divided by sex into 30 steel-framed pens (2.16 m² ) and randomly assigned to five grower (22–35 d) and finisher (36–42 days) maize-based groups: commercial; soyabean, sprouted cowpeas with no BSFLM; sprouted cowpeas, low fat, with 5% BSFLM; sprouted cowpeas, high fat, with 5% BSFLM; and sprouted cowpeas with 10% BSFLM. Weekly pen feed intake, live weight gain, and feed conversion ratio were evaluated, with carcass measurements at 42 d. During the grower phase, broilers on commercial feed outperformed those on cowpea diets in growth and feed conversion. In the finisher phase, broilers on commercial feed had higher feed intake than those on sprouted cowpeas with 10% BSFLM. Broilers on commercial feed had higher feed intake, weight gain, and slaughter weights, and better feed conversion. Male broilers had higher feed intake during the grower phase and gained more weight during finishing. The 10% BSFLM reduced meat drip loss. BSFLM increased liver size and abdominal fat, especially in females, with an inverse effect on breast meat yield. BSFLM improved the efficacy of the sprouted-cowpea diets. Broiler performance followed the order commercial feed > sprouted cowpeas, 10% BSFLM > sprouted cowpeas, high-fat, 5% BSFLM > sprouted cowpeas, low-fat, 5% BSFLM > non-supplemented sprouted cowpea diet.

Effect of pipping rate and hatching nature on the development of ostrich chicks

M. Brand — 2024-12-11

High embryonic mortality is concerning because of the effect on commercial ostrich farming. The number of viable chicks can be improved by appropriate interventions in the hatching chicks. Data from 2 683 fertile eggs were collected from the commercial, pair-bred ostrich flock on the Oudtshoorn Research Farm, South Africa, with 169 chicks being reported. Fertile eggs were randomly divided into three groups on days 41, 42, and 43 of incubation. There were four treatments: hatchlings that reached climax and broke free from the eggshell themselves (T1), hatchlings that were assisted to reach climax at the first signs of external pipping (T2), hatchlings that were removed from the eggshell at the first sign of external pipping (T3), and eggs that pipped internally after 43 d but failed to pip externally were cracked (T4). Clinical measurements (heart rate, body temperature, and oedema) were taken at hatch. The chicks were weighed for 7 d and then on days 28, 84, 147, 227, 300 and 365. Chicks that were assisted after internal pipping took longer to hatch. The heart rate of 115 beats per minute (bpm) for chicks hatching on their own was lower than the 132 bpm recorded for the other treatment groups. Up to day two after hatching, a decline in chick weight of ~4% was found. Chick weight increased from 0.85 kg to 1.11 kg in the first week. At 147 d, body weights between treatments were 12.6% higher for the chicks hatching on their own compared with the chicks where the eggshell was cracked, and 24.6% higher for chicks where the eggshell was removed after external pipping. Chicks benefitted by climaxing themselves, but for chicks struggling to hatch, this study provides guidance to hatchery operators on the specific stages where monitoring and assistance is important to improve hatchability.