Application of random regression models to the genetic evaluation of cow weight in Bonsmara cattle of South Africa

Repeated records (n = 58, 295) of Bonsmara cows were used to evaluate mature cow weight (CW), using random regression animal models (RRM). Cows (n = 11, 847), age two to 11 years (AY), were weighed at weaning of their calves. Data were analysed with the Restricted Maximum Likelihood (REML) procedure, using orthogonal (Legendre) polynomials on age in months (AM). The model included fixed regression on AM (range from 30 to 138 mo) and the effect of herd-measurement date concatenation. Random parts of the model were RRM coefficients for additive and permanent environmental effects, while residual effects were modelled to account for heterogeneity of variance by AY. Estimates of variances increased with cow age, though tended to be flat at older ages. Heritability estimates ranged from 0.39 to 0.47, and were comparable with estimate of 0.41 obtained using a simple repeatability model (SRM). Estimates of genetic correlations were greater than 0.82 among measures of weight at all ages. The resulting covariance functions were used to estimate breeding values of each animal along the age trajectory. Genetic trends for CW over the years showed only a slightly increasing pattern, suggesting that CW did not change much, and was similar whether SRM or RRM was used. Results suggest that selection for CW could be effective and that RRM could be useful for the National Genetic Evaluation of CW in Bonsmara cattle. However, given the complexity of the RRM, for practical purposes a SRM might be an acceptable approximation for prediction of breeding values. Key Words: Covariance functions, Mature weight, Genetic parameters, Beef cattle South African Journal of Animal Science Vol.34(3) 2004: 166-17

Investigating Strategies for Mitigating and Avoiding Expert Blind Spot Development in Teaching English Attributive Adjectives

Teaching is a prominent paraphernalia that brings numerous insights for developing learners’ competence in educational concerns. However, teaching English to non-native learners poses challenges as innovative strategies are scant. Sometimes teachers overlook the difficulties experienced by novices when they approach a new English grammatical domain. Psychological expert blind spot sporadically and intuitively develops due to teachers’ ignorance. The paper investigated strategies for mitigating and avoiding expert blind spot in teaching English attributive adjectival phrases at Khwevha High School in Limpopo Province, South Africa. Quantitative and qualitative research approaches were adopted to corroborate the findings. A questionnaire was used to collect data from 35 selected Grade 10 respondents using a simple random sampling technique. Qualitatively, semi-structured interviews were conducted on two purposely sampled schoolteachers from Dzindi Circuit, based on the researcher’s preference for obtaining an in-depth understating of the topic. Initially, learners were incompetent in using adjectives but after employing ‘points of entry’, offering ‘explanations’, presenting ‘structures’ and checking ‘comprehension’ strategies, learners improved considerably. The paper underscores using the identified strategies to mitigate and avoid the advancement of the expert blind spot in teaching English attributive adjectives

Facilities management awareness amongst high school learners and teachers in the Soutpansberg west circuit in the Limpopo province

The Facilities Management (FM) profession in South Africa needs to start recognising and acknowledging the importance of formal education amongst the population. The question of FM being a career normally receives shallow responses; and it sometimes leads to a contradiction. The FM profession seems to be taking an ‘as it is’ approach, when it comes to the establishment of an education agenda; since there is no clear evidence regarding alignment and transition from high school to tertiary level, and then to the workplace. The level of awareness plays a significant role in all elements of FM practice. Even at the present moment, FM is still not a career of choice, meaning that anyone can be a facilities manager. There are parts of South Africa where the population is unaware of FM. Some had never heard about it at all. It was important to establish the level of awareness: with the intention of developing a critical awareness of FM as a career path amongst high school learners and teachers in the Soutpansberg West Circuit, in order to inform them of a possible career choice in FM. In this study, a mixed-model research methodology was used, which combines both qualitative and quantitative research approaches. A population was identified from which a sample of 14 high schools, 87 high school teachers and 2 299 high school learners was drawn. A ‘fit for purpose’ questionnaire was distributed to the participants. The data were collected by means of a survey. It focused on a survey; and it used a questionnaire that was composed of multiple closed-ended or quantitative-type items, as well as several open-ended or qualitative-type items. Thematic analysis was used for the open-ended questions. This study has successfully managed to determine the awareness levels of high school learners and teachers relating to FM, the need for FM awareness in high schools; and whether there were high school learners who wished to become facilities managers in the future. FM companies, tertiary institutions, and high schools must collaborate in the development of the FM career-guidance programme, in order to increase awareness amongst the teachers and learners. There were students who indicated that they were interested in FM as their career of choice

Short Communication Single nucleotide polymorphisms in five adipokine genes in dairy cattle populations

Genetic diversity in candidate genes for fitness and production traits was explored in three populations of dairy cattle. The study focused on adipokines, including leptin (LEP), tumor necrosis factor alpha (TNF), interleukin-8 (IL8) and interleukin-10 (IL10) as candidate genes. The three populations of interest included young Jersey and Holstein (modern Holstein) sires, and Holstein sires born prior to 1970 (traditional Holstein). Pools of DNA representing each sire group were used as template to generate PCR products for sequencing and identification of single nucleotide polymorphisms (SNP). Sequences of PCR products were assembled and SNPs identified using Sequencher 4.5 software. One SNP representing each gene and a previously reported SNP in LEP were selected for genotyping across all bulls. A multiplexed genotyping assay was developed using the ABI PRISM SNaPshot Multiplex Kit. Allele and genotypic frequencies were determined for each sire group, and genotypic frequencies were in agreement with Hardy-Weinberg equilibrium. Allele frequencies were compared among sire groups using the chi-square test. A significant difference between Jersey and Holstein was observed for all genes, and modern and traditional Holstein groups differed for the previously described LEP and IL10 SNP. Although allele frequency differences between modern and traditional Holsteins may reflect the effect of selection pressure for production traits on these genomic regions, random genetic drift or sampling bias could also have contributed to the observed differences. Keywords: Fitness traits; genetic markers; adipokines; dairy cattle South African Journal of Animal Science Vol. 37 (3) 2007: pp.154-15

Estimates of genetic parameters and effect of inbreeding on milk yield and composition in South African Jersey cows

The effect of inbreeding on the 305-d yields of milk, fat and protein, and the percentages of fat and protein in the first three lactations was estimated using records on the South African Jersey cows that participated in the National Dairy Animal Improvement Scheme. Inbreeding coefficients were estimated using the entire pedigree records of the Jersey breed and ranged from 0 to 42%. Data were analyzed using a repeatability animal model. The statistical model included the fixed effects of herd-year-season, age of the cow at calving, calving interval, inbreeding as a discrete or continuous variable and random effects of direct additive genetic, permanent environment of the cow and the residual effects. The multitrait derivative-free REML algorithm was used to obtain estimates of the variance components, ratios and empirical best linear unbiased estimates of the effects of inbreeding. Estimates of heritability were 0.26 (±0.009), 0.19 (±0.008), 0.23 (±0.008), 0.39 (±0.009), and 0.53 (±0.009) for milk, fat and protein yields and fat and protein percent, respectively. Corresponding estimates of the ratio of permanent environmental effect of the cow to total phenotypic variance were 0.20 (±0.008), 0.18 (±0.007), 0.21 (±0.007), 0.14 (±0.008) and 0.13 (±0.008). The regression coefficients for yields (kg) of milk, fat and protein were -15.42 (±1.13), -0.64 (±0.05), and -0.59 (±0.04), and 0.0011 (±0.0005) and 0.0003 (±0.0003) for percent (%) of fat and protein for each 1% increase in inbreeding, respectively. These results provide evidence of inbreeding depression for milk yield and composition traits in the South African Jersey population. Keywords: Dairy cattle, inbreeding depression, 305-d yield South African Journal of Animal Science Vol. 38 (2) 2008: pp. 119-12

Analysis of stayability in South African Angus cattle using a threshold model

The objectives of the study were to estimate genetic parameters for stayability in the South African Angus cattle and to compare the sire and animal threshold models. Data and pedigree information were obtained from the Integrated Registration and Genetic Information System of South Africa. Stayability was defined as a probability that a cow remained in the herd until four (STAY4), five (STAY5), six (STAY6), seven (STAY7) and eight years of age (STAY8), given that she was a dam. Cows that were in the herd by a specific age were assigned a “1” or a “0”, otherwise. The proportions of successful stayability were 0.63, 0.57, 0.49, 0.42, and 0.37 for STAY4, STAY5, STAY6, STAY7 and STAY8, respectively. Estimates of genetic parameters were obtained from sire and animal threshold models using AIREML algorithm. The model included the fixed effect of contemporary group and random effects of sire or animal genetic effect and the residual. Heritability estimates from the sire model were 0.26 ± 0.08, 0.26 ± 0.09, 0.30 ± 0.09, 0.24 ± 0.10 and 0.27 ± 0.11 for STAY4, STAY5, STAY6, STAY7 and STAY8, respectively. Corresponding estimates from the animal model were 0.20 ± 0.11, 0.20 ± 0.11, 0.20 ± 0.12, 0.18 ± 0.13 and 0.20 ± 0.14. Estimates from the sire and animal models were consistent. Results from the current study indicate that direct selection for stayability could be effective. However, the long generation interval required to obtain accurate estimates of genetic merit may slow genetic progress for stayability at older ages

The effect of herd of origin by year on post-weaning traits of young beef bulls at centralized testing centres in South Africa

The effects of herd of origin by year on the average daily gain (ADG), average daily feed intake (DFI), shoulder height (SDH) and scrotal circumference (SCR) of beef bulls at centralized test centres in South Africa were investigated using data of Bonsmara cattle. Data consisted of post-weaning traits of beef bulls tested between 1990 and 2003, with available weaning weight (WWT) and weaning management group information as well as weaning weights of their contemporaries. A multiple-trait animal model including ADG, DFI, SDH and SCR, together with WWT was used. The model for WWT (adjusted to 205 days of age and age of dam by sex of calf classes) included the fixed effect of management group and random effects of direct additive genetic and dam effects, while the model for post-weaning traits included fixed effects of test group and age of the bull at the end of test (fitted as linear and quadratic regressions) and random effects of direct additive genetic and herd of origin by year (HY) effects. Variance components were estimated using REML procedures. Heritability estimates were 0.27, 0.34, 0.36, 0.51 and 0.46 for WWT, ADG, DFI, SDH and SCR, respectively. The contribution of HY effects to the phenotypic variance of ADG, DFI, SDH and SCR were 9%, 10%, 6% and 5%, respectively. Inclusion of HY effect resulted in the re-ranking of sires, with rank correlations ranging from 0.86 to 0.98 among the top sires, across traits. These results suggest that the HY effect should be included in the model for the national genetic evaluation of post-weaning traits of beef bulls measured at centralized testing centres in South Africa. South African Journal of Animal Science Vol. 36(1) 2006: 33-3

Approaches for Mastering Coordinative Appositions Exceptions in Simple Present Tense

Coordinative appositions bring coordination between words, phrases, and clauses in communication. They are one grammatical feature requiring second language learners’ competence in its usage. However, the use of the coordinative appositions exceptions in English language is concerning. They usually deviate from the exceptions involved in the use of the coordinating conjunction ‘and’ in the simple present tense. In South African schools, English First Additional Language learners are affected by this learning adversity. The research paper aimed at investigating a suitable approach for mastering the coordinative appositions exceptions in the simple present tense. A quantitative research approach was used by the researchers because the findings could be reduced to numbers and percentages using statistical procedures. Using a questionnaire, data were collected from the respondents. Statistical Package for Social Sciences version 22 and IBM SPSS version 25 both were utilised to analyse data after the findings from each software were collated for validity purposes. A random sampling technique was used to sample 8 respondents from an overall enrolment of 65 Grade eight learners at Andries Mugaguli Secondary School in Limpopo Province, South Africa. Although pre-test findings showed poor performance in using ‘Hangman’ approach, after utilising the ‘coordinating conjunction board game, learners’ performance improved remarkably. The research recommends regular practise in the exceptions involved in the use of the coordinating conjunction ‘and’ in the simple present tense

Rate of inbreeding and effective population size in four major South African dairy cattle breeds

Pedigree information on the registered South African Ayrshire (n = 47 116), Guernsey (n = 18 766), Holstein (n = 892 458) and Jersey (n = 314 403) breeds was analyzed to determine the rate of inbreeding and effective population sizes for the period 1960 to 2003. Inbreeding coefficients were calculated using the Animal Breeder's Tool Kit. The mean inbreeding coefficients for 2003 were 2.02%, 2.04%, 2.30%, and 3.05% for the Ayrshire, Guernsey, Holstein and Jersey, respectively. The corresponding rates of inbreeding per year were 0.05%, 0.05%, 0.06%, and 0.07% indicating that inbreeding is accumulating at a slightly higher rate in Jersey compared to the other three breeds. However, the rates of inbreeding in the current study are still considerably lower than the acceptable rate of less than 0.5% per year. Estimates of effective population sizes were 148, 165, 137, and 108 for the Ayrshire, Guernsey, Holstein and Jersey, respectively. Results indicate that the impact of inbreeding on genetic variability is still minimal. However, the impact of inbreeding on phenotypic performance on traits of economic importance was not investigated in the current study and should therefore receive future consideration. South African Journal of Animal Science Vol. 36(1) 2006: 50-5