Using a lamb's early-life liveweight as a predictor of carcass quality

Efficacy of a Lidocaine-Impregnated Elastrator Band for Castration and Tail Docking in Lambs

The primary objective of this study was to demonstrate the non-inferiority between lidocaine-impregnated ligation bands (LLBs) and control bands (CBs) with respect to the efficacy of castration and tail docking. Secondary objectives were to compare castration and tail-docking success, evaluate local site reactions, and compare average daily gain (ADG) between the treatment groups. A total of 238 male lambs were enrolled and randomly assigned to receive LLBs or CBs on their tail and scrotum. Lambs were weighed, had a health assessment, and the band site was observed on -3, 7, 14, 21, 28, 35, and 42 days after the bands were applied. A linear regression model was built to assess average daily gain, whereas a repeated measures model was used to evaluate body weight differences at each of the measured timepoints. Furthermore, logistic regression models were used to evaluate associations with casting outcomes. Few differences were noted between treatment groups with respect to casting success for the scrotum and tail and ADG over the entire experimental period. Non-inferiority calculations demonstrated no differences in tail docking and scrotal casting success, with casting occurring for the majority of animals by d 21 and d 42 for castration and tail docking, respectively. However, lambs receiving LLBs gained more weight from d -3 to 7 (+0.03 kg/d; 95% CI: 0 to 0.07), which may be an indication of effective pain control during the first week following band application. Overall, the use of an LLB does not affect the time to successful casting of the tail and could improve short-term growth when compared to a control band. Further studies are needed to compare LLBs to multimodal methods of pain relief.

Using fat thickness and longissimus thoracis traits real-time ultrasound measurements in Black Belly ewe lambs to predict carcass tissue composition through multiresponse multivariate adaptive regression splines algorithm

The main idea of the current study was to estimate carcass tissue composition using fat thickness and longissimus thoracis (LT) traits real-time ultrasound measurements (USM) in Black Belly ewe lambs through multiresponse multivariate adaptive regression splines (MARS) algorithms. Twenty-four hours before slaughter, subcutaneous (SFT) and kidney-fat thickness (KFT), LT depth (LTD), width (LTA, cm) and area (LTMA) were measured in 60 lambs (BW of 26.40 ± 7.01 kg). Information on carcass and non-carcass components was recorded after slaughter. The total carcass muscle (TCM), total carcass bone (TCB), and total carcass fat (TCF) had a low to high correlation (P < 0.01) with BW, cold carcass weight (CCW), and LTD, SFT, KFT, and LDMA. The CCW (%65.58) and SFT (%16.70) were the most effective variables, whilst LTD (%9.57) and LTMA (%8.15) were the lowest variables for determining TCB, TCM, and TCF. The multiresponse MARS algorithm provides an accurate and efficient means of estimating TCF, TCB, and TCM.

Impact of inclusion non-additive effects on genome-wide association and variance's components in Scottish black sheep

CONTEXT

It's well-documented that most economic traits have a complex genetic structure that is controlled by additive and non-additive gene actions. Hence, knowledge of the underlying genetic architecture of such complex traits could aid in understanding how these traits respond to the selection in breeding and mating programs. Computing and having estimates of the non-additive effect for economic traits in sheep using genome-wide information can be important because; non-additive genes play an important role in the prediction accuracy of genomic breeding values and the genetic response to the selection.

AIM

This study aimed to assess the impact of non-additive effects (dominance and epistasis) on the estimation of genetic parameters for body weight traits in sheep.

METHODS

This study used phenotypic and genotypic belonging to 752 Scottish Blackface lambs. Three live weight traits considered in this study were included in body weight at 16, 20, and 24 weeks). Three genetic models including additive (AM), additive + dominance (ADM), and additive + dominance + epistasis (ADEM), were used.

KEY RESULTS

The narrow sense heritability for weight at 16 weeks of age (BW16) were 0.39, 0.35, and 0.23, for 20 weeks of age (BW20) were 0.55, 0.54, and 0.42, and finally for 24 weeks of age (BW24) were 0.16, 0.12, and 0.02, using the AM, ADM, and ADEM models, respectively. The additive genetic model significantly outperformed the non-additive genetic model (p < 0.01). The dominance variance of the BW16, BW20, and BW24 accounted for 38, 6, and 30% of the total phenotypic, respectively. Moreover, the epistatic variance accounted for 39, 0.39, and 47% of the total phenotypic variances of these traits, respectively. In addition, our results indicated that the most important SNPs for live weight traits are on chromosomes 3 (three SNPS including s12606.1, OAR3_221188082.1, and OAR3_4106875.1), 8 (OAR8_16468019.1, OAR8_18067475.1, and OAR8_18043643.1), and 19 (OAR19_18010247.1), according to the genome-wide association analysis using additive and non-additive genetic model.

CONCLUSIONS

The results emphasized that the non-additive genetic effects play an important role in controlling body weight variation at the age of 16-24 weeks in Scottish Blackface lambs.

IMPLICATIONS

It is expected that using a high-density SNP panel and the joint modeling of both additive and non-additive effects can lead to better estimation and prediction of genetic parameters.

Genetic (co)variance components for slaughter traits in a multi-breed sheep population

Carcass value is one of the main contributors to revenue in meat sheep enterprises, while age at slaughter is also a major component to the cost of production. Despite the contribution of such traits to overall profit, little is actually known on the extent of exploitable genetic variability in the traits that govern carcass value (i.e. carcass weight, carcass conformation, carcass fat) and age at slaughter, especially independent of each other. The objective of the present study was to estimate genetic (co)variances for and among carcass weight, carcass conformation, carcass fat, kill-out percentage and age at slaughter as well as their genetic (co)variances with traits measured earlier in life. Data consisted of slaughter records from 15 714 lambs, with 12 630 of these lambs having at least one live weight measure. The heritability (SE) of carcass weight, carcass conformation, carcass fat, kill-out percentage, and age at slaughter was 0.14 (0.02), 0.19 (0.02), 0.08 (0.01), 0.22 (0.03), and 0.16 (0.02), respectively. The maternal heritability for age at slaughter was 0.07 (0.02); no maternal genetic influence was found on any of the other slaughter traits. The coefficient of genetic variation for carcass weight and age at slaughter was 3 and 8%, respectively. The correlations between the direct genetic effects for live weight throughout life, and carcass weight were weak up to weaning but were strong (0.83) thereafter. The correlation between the direct genetic effects of birth weight and age at slaughter was zero, but varied from -0.91 to -0.56 between live weight measured later in life and age at slaughter. Results demonstrate significant exploitable genetic variability in a range of slaughter traits with the prediction of genetic merit for carcass traits and age at slaughter being possible using live weight measures taken on live animals. For example, the accuracy of selection for slaughter traits (comprising of age at slaughter, carcass conformation and carcass fat) from weaning weight records available on 100 progeny was 0.37; when slaughter data were also available for 10 progeny, the accuracy of selection increased to 0.56.

Pre-weaning performance and commercial growth curve in Dorper, Katahdin, and Romanov crossed lambs in a highland zone from central Mexico

The aim was to evaluate the pre-weaning productive performance and growth curve of Dorper*Katahdin (DPr; n = 46), Kathadin*Kathadin (KTn; n = 204) and Romanov*Kathadin (RMv; n = 40) of commercial crossed lambs from central Mexico. We considered 1450 data from 290 crossbred lambs. The variables contemplated in this study were cross (CR), lambing type (LT), sex, birth weight (BW), weaning weight (WW), test days (TD), and daily weight gain (DWG). Correlation analysis and adjustment of growth curve were performed. Differences in CR and sex were found only in BW (p < 0.05). No differences in DWG, WW, and TD (p > 0.05) by CR and sex were found. Single lambing had the highest (p < 0.05) BW, WW, and DWG. Phenotypic correlations differ among crosses. Lambs crossed with DPr presented the highest values in parameters a and b and the lowest in c. The productive behavior of DPr, KTn, and RMv cross with KTn lambs in central Mexico is similar in the pre-weaning period; however, the growth curve and parameters that characterize it suggest that DPr lambs show a tendency to enhance productive behavior in this period.

Growth and Slaughter Characteristics of Weaning Male Kids of Turkish Native Goat Breeds

There is little knowledge about the carcass potential of Turkish native goat breeds raised under different rearing conditions. It is necessary to compare the carcass characteristics of these breeds to minimize the effect of the rearing conditions. Therefore, this study aims to compare the growth, slaughter, and carcass characteristics of male kids at weaning age to eliminate the impact of rearing conditions. Kids born to Angora (n = 6), Hair (n = 6), Honamlı (n = 6), and Kilis (n = 6) Turkish native goat breeds, ranging in age from 2-3 years, were slaughtered at 90 days of weaning age and carcass characteristics were determined immediately. There were differences (p < 0.05) among breeds in terms of birth weight (BW) and daily weight gain (DWG) from birth to weaning age. Honamlı kids had higher BW and DWG than those of other breeds (p < 0.05). Similarly, carcass weights (hot-cold) and yields (hot-cold) of Honamlı kids were higher compared to kids born to other breeds (p < 0.05). Additionally, Honamlı and Hair kids had higher longissimus-dorsi (LD), and semitendinosus (ST) muscle weights compared to Kilis and Angora kids. Interestingly, Kilis kids had lower BW and DWG than those of other breeds (p < 0.05). There were significant differences (p < 0.05) among breeds in terms of non-carcass parts and organ weights. Positive correlations were calculated between cross-sectional area and weight (r = 0.793; p < 0.01), length and weight (r = 0.723; p < 0.01), and depth and weight (r = 0.698; p < 0.01) in LD muscle of all kids. A similar correlation trend was calculated for the ST muscle (cross-sectional area and weight; r = 0.699; p < 0.01, length and weight; r = 0.751; p < 0.01, and depth and weight; r = 0.528; p < 0.05) in all kids. In conclusion, the present study results showed that Honamlı kids could be used for fattening material due to their good carcass quality compared to other native breeds.

Quantifying the value of on-farm measurements to inform the selection of key performance indicators for livestock production systems

The use of key performance indicators (KPIs) to assist on-farm decision making has long been seen as a promising strategy to improve operational efficiency of agriculture. The potential benefit of KPIs, however, is heavily dependent on the economic relevance of the metrics used, and an overabundance of ambiguously defined KPIs in the livestock industry has disincentivised many farmers to collect information beyond a minimum requirement. Using high-resolution sheep production data from the North Wyke Farm Platform, a system-scale grazing trial in southwest United Kingdom, this paper proposes a novel framework to quantify the information values of industry recommended KPIs, with the ultimate aim of compiling a list of variables to measure and not to measure. The results demonstrated a substantial financial benefit associated with a careful selection of metrics, with top-ranked variables exhibiting up to 3.5 times the information value of those randomly chosen. When individual metrics were used in isolation, ewe weight at lambing had the greatest ability to predict the subsequent lamb value at slaughter, surpassing all mid-season measures representing the lamb's own performance. When information from multiple metrics was combined to inform on-farm decisions, the peak benefit was observed under four metrics, with inclusion of variables beyond this point shown to be detrimental to farm profitability regardless of the combination selected. The framework developed herein is readily extendable to other livestock species, and with minimal modifications to arable and mixed agriculture as well.

Data to identify key drivers of animal growth and carcass quality for temperate lowland sheep production systems

With the growing demand for animal-sourced foods and a serious concern over climate impacts associated with livestock farming, the sheep industry worldwide faces the formidable challenge of increasing the overall product supply while improving its resource use efficiency. As an evidence base for research to identify key drivers behind animal growth and carcass quality, longitudinal matched data of 741 ewes and 2978 lambs were collected at the North Wyke Farm Platform, a farm-scale grazing trial in Devon, UK, between 2011 and 2019. A subset of these data was subsequently analysed in a study to assess the feasibility of using a lamb's early-life liveweight as a predictor of carcass quality [1]. The data also have the potential to offer insight into key performance indicators (KPIs) for the sheep industry, or what variables farmers should measure and target to increase profitability.