A live weight-heart girth relationship for accurate dosing of east African shorthorn zebu cattle

Predicting Body Weight in Pre-Weaned Holstein-Friesian Calves Using Morphometric Measurements

Regularly weighing calves helps to assess the efficiency of the rearing period and contributes to animal welfare by allowing more precise feeding and medication application in dairy farming, but many farmers do not weigh their calves regularly. Improving the feasibility of this process is, therefore, important. The use of morphometric measurements has been used to estimate the weight of cattle. However, many studies have focused on adult animals or used a wide age range. As calves experience allometric tissue growth, specific models for certain ranges might be more accurate. Therefore, the aim of this work was to develop a weight estimation model specific for pre-weaned Holstein-Friesian calves using morphometric measurements and to compare the model with another equation previously validated for the same breed with young and adult animals. From four dairy farms, 237 measurements of body weight, heart girth, abdominal girth, hip height, withers height, and body length were taken from Holstein-Friesian male and female calves. Linear and non-linear regression analysis was used to test the relationship between body weight and morphometric measurements, with age, sex, and farm as possible explanatory variables. Selected models were compared with goodness of fit and agreement tests. The final model was able to accurately predict body weight (R2 = 0.96) with a mean difference of -1.4 ± 3.24 kg. Differences in the relationship between body weight and morphometric traits were observed between farms, but not between males and females. The genetics of the animal population at farm level may be responsible for this variability and further studies are needed to understand this variability and improve weight prediction models. The developed model was able to perform better in the agreement tests than the previously validated model for Holstein-Friesian animals, suggesting that different equations should be used depending on the growth phase the animal is in. In addition, a web application has been developed to facilitate the use of the developed model by farmers. This avoids the use of calibrated weight bands, which are usually calibrated for a broader age range or for beef cattle.

Prediction of body weight of Curraleiro Pé-Duro cattle based on morphometric measurements

Cattle weight development is highly correlated with some body measurements. Based on the relationship between morphometric measurements and body mass, our aim was to develop regression equations to estimate the body weight of Curraleiro Pé-Duro (CPD) cattle to be used in farms that lack access to weighting scales. Data from 1023 animals from four farms on withers height (WH), body length (BL), body score (BS), heart girth (HG), permanent teeth (PT), scrotal perimeter (SP), and live weight were used. The animals were classified into five categories depending on age and/or sex: newborns (NB), calves, weaned animals, cows, and bulls. The best models are GLM with Gamma, Gamma, inverse Gaussian, Gaussian, and Gamma distributions for NB, calves, weaned animals, cows, and bulls, respectively. Predictive modeling for bulls was the best performing overall, with a correlation of 0.97 between the estimated by the model and the obtained with a weighting scale. For NB, calves, weaned animals, and cows, the correlation (r) was 0.85, 0.90, 0.95, and 0.87, respectively. The evaluated models are adequate to be used as a technical solution to estimate weight in a cattle production system.

Models to predict live weight from heart girth in crossbred beef heifers

The objective of this study was to develop and evaluate linear, quadratic, and exponential mathematical models to predict live weight (LW) from heart girth (HG) in crossbred heifers raised in tropical humid conditions in Mexico. Live weight (363.32 ± 150.88 kg) and HG (166.83 ± 24.88 cm) were measured in 400 heifers aged between 3 and 24 months. Linear and non-linear regression was used to construct the prediction models. The goodness of fit of the models was evaluated using the Akaike information criterion (AIC), the Bayesian information criterion (BIC), coefficient of determination (R²), mean squared error (MSE), and root MSE (RMSE). In addition, the developed models were evaluated through internal and external cross-validation (k-folds) using independent data. The ability of the fitted models to predict the observed values was evaluated based on the root mean square error of prediction (RMSEP), R², and mean absolute error (MAE). The correlation coefficient between LW and HG was r = 0.98 (P < 0.001). The quadratic model showed the lowest values of MAE (736.57), RMSEP (27.13), AIC (3783.95), and BIC (3799.91). Additionally, this model exhibited better goodness-of-fit values regarding external and internal validation criteria (higher R² and lower RMSEP and MAE), thus having better predictive performance. The RMSE represented about 8% of the observed LW. Heart girth is highly correlated (r = 0.98) with LW. The quadratic model showed a high predictive capacity for crossbred heifers kept in tropical conditions.

Designing Statistical Models for Holstein Rearing Heifers' Weight Estimation from Birth to 15 Months Old Using Body Measurements

Simple Summary

The growth monitoring process represents an important part of rearing heifers. The use of a scale is not feasible in some breeding conditions; it may be interesting to investigate the possibility of evaluating body weight (BW) with body measurements. The aim of this study was to estimate heifers’ weight based on their body dimension characteristics. A total of 25 Holstein rearing heifers were monitored after birth, weekly until 2 months of life and monthly until 15 months of age. Animals were weighed, and their wither height (WH), shin circumference (SC), heart girth circumference (HG), body length (BL), hip width (HW) and body condition score (BCS) were measured using tape measure. Equations were built with a stepwise regression to estimate the BW at each time using body measures for the study group. Equations were able to estimate the BW of heifers under a 0.800 kg as an average weight gain target using different variables, representing an alternative method of BW evaluation without a scale. Three variables or fewer were needed for BW estimation at crucial growing times, making these models feasible for use in the field. Different growing rate target may be studied in order to evaluate possible modifications to our equations.

Abstract

Body measurements could be used to estimate body weight (BW) with no need for a scale. The aim was to estimate heifers weight based on their body dimension characteristics. Twenty-five Holstein heifers represent the study group (SG); another 13 animals were evaluated as a validation group (VG). All the heifers were weighed (BW) and their wither height (WH), shin circumference (SC), heart girth circumference (HG), body length (BL), hip width (HW) and body condition score (BCS) were measured immediately after birth, and then weekly until 2 months and monthly until 15 months old. Equations were built with a stepwise regression in order to estimate the BW at each time using body measures for the SG. A linear regression was applied to evaluate the relationship between the estimated BW and the real BW. Equations found were to be statistically significant (r² = 0.688 to 0.894; p < 0.0001). Three variables or fewer were needed for BW estimation a total of 11/23 times. Regression analysis indicated that the use of HG was promising in all the equations built for BW estimation. These models were feasible in the field; further studies will evaluate possible modifications to our equations based on different growing rate targets.

Feasibility of heart girth models in estimating live weight of fat-long-tailed sheep

Fat deposition in the brisket of Ethiopian fat‐long‐tailed sheep may interfere with the correlation between heart girth (HG) and live weight (LW), bringing into question the accuracy of HG models for LW prediction that are currently in use. This study assessed the accuracy of published HG‐based prediction models of the live weight of Ethiopian sheep breeds. Furthermore, the study identified accurate and robust models that predict the LW of the sheep using HG. Live weight and HG of 1,020 sheep from Bonga, Adilo and Horro breeds were measured. First, data collected from the study was used to gauge the preciseness of previously published prediction models of each breed. Second, the data of individual breeds were divided into a calibration set for model construction and a validation set for model validation. Live weight was regressed on HG to construct simple linear, Box‐Cox, quadratic and allometric prediction models. Prediction error of published models was >20%. Models constructed for each breed did not differ in R². However, only simple linear models with transformed LW (Adilo: Log₁₀(LW) = 0.408 + 0.015*HG, Bonga: Log₁₀(LW) = −36.6 + 0.882*HG, Horro: LW^0.5 = −1.26 + 0.085*HG) had homogenous residuals and prediction error of ≤ 10%. Heart girth models currently used to predict LW of Adilo, Bonga and Horro sheep of Ethiopia are not sufficiently accurate as they have PE higher than 10%. Prediction models generated by the current study could replace the published models for an accurate estimation of LW of the three breeds for husbandry, marketing and veterinary purposes.

The published models currently in use are inaccurate in estimating live weight of fat‐long‐tailed Ethiopian sheep The study generated simple and feasible heart girth models to predict live weight of fat‐long‐tailed Ethiopian sheep.

Reflections on IDEAL: What we have learnt from a unique calf cohort study

The year 2020 marks a decade since the final visit was made in the ‘Infectious Diseases of East African Livestock’ (IDEAL) project. However, data generation from samples obtained during this ambitious longitudinal study still continues. As the project launches its extensive open-access database and biobank to the scientific community, we reflect on the challenges overcome, the knowledge gained, and the advantages of such a project. We discuss the legacy of the IDEAL project and how it continues to generate evidence since being adopted by the Centre for Tropical Livestock Genetics and Health (CTLGH). We also examine the impact of the IDEAL project, from the authors perspective, for each of the stakeholders (the animal, the farmer, the consumer, the policy maker, the funding body, and the researcher and their institution) involved in the project and provide recommendations for future researchers who are interested in running longitudinal field studies.

Multiple association analysis of loci and candidate genes that regulate body size at three growth stages in Simmental beef cattle

Background

Body size traits as one of the main breeding selection criteria was widely used to monitor cattle growth and to evaluate the selection response. In this study, body size was defined as body height (BH), body length (BL), hip height (HH), heart size (HS), abdominal size (AS), and cannon bone size (CS). We performed genome-wide association studies (GWAS) of these traits over the course of three growth stages (6, 12 and 18 months after birth) using three statistical models, single-trait GWAS, multi-trait GWAS and LONG-GWAS. The Illumina Bovine HD 770 K BeadChip was used to identify genomic single nucleotide polymorphisms (SNPs) in 1217 individuals.

Results

In total, 19, 29, and 10 significant SNPs were identified by the three models, respectively. Among these, 21 genes were promising candidate genes, including SOX2, SNRPD1, RASGEF1B, EFNA5, PTBP1, SNX9, SV2C, PKDCC, SYNDIG1, AKR1E2, and PRIM2 identified by single-trait analysis; SLC37A1, LAP3, PCDH7, MANEA, and LHCGR identified by multi-trait analysis; and P2RY1, MPZL1, LINGO2, CMIP, and WSCD1 identified by LONG-GWAS.

Conclusions

Multiple association analysis was performed for six growth traits at each growth stage. These findings offer valuable insights for the further investigation of potential genetic mechanism of growth traits in Simmental beef cattle.

Improved region-specific emission factors for enteric methane emissions from cattle in smallholder mixed crop: livestock systems of Nandi County, Kenya

National greenhouse-gas (GHG) inventories in most developing countries, and in countries in Sub-Saharan Africa in particular, use default (Tier I) GHG emission factors (EFs) provided by the Intergovernmental Panel on Climate Change (IPCC) to estimate enteric methane (CH4) emissions from livestock. Because these EFs are based on data primarily from developed countries, there is a high degree of uncertainty associated with CH4 emission estimates from African livestock systems. Accurate Tier II GHG emission reporting from developing countries becomes particularly important following the Paris Climate agreement made at COP21, which encourages countries to mitigate GHG emissions from agricultural sources. In light of this, the present study provides improved enteric CH4 emission estimates for cattle in Nandi County, Western Kenya, representing a common livestock production system found in East Africa. Using the data from measurements of liveweight and liveweight change, milk production and locomotion collected from 1143 cattle in 127 households across 36 villages over three major agro-ecological zones covering a full year, we estimated total metabolic energy requirements. From this and assessments of digestibility from seasonally available feeds, we estimated feed intake and used this to calculate daily CH4 production by season, and, subsequently, created new EFs. Mean EFs were 50.6, 45.5, 28.5, 33.2 and 29.0 kg CH4/head.year for females (&gt;2 years), males (&gt;2 years), heifers (1–2 years), young males (1–2 years) and calves (&lt;1 year) respectively, and were lower than the IPCC Tier I estimates for unspecified African adult cattle, but higher for calves and young males. Thus, using IPCC Tier 1 EFs may overestimate current enteric CH4 emissions in some African livestock systems.

Simple and robust model to estimate liveweight of Ethiopian Menz sheep

Heart girth (HG) bands have been predominantly used in Ethiopia by smallholder farmers, traders and extension workers to estimate liveweight (LW) of livestock. They are produced using recommended and published predictive models from Ethiopia. More recently, some farmers and traders have abandoned the bands due to perceived inaccuracy of LW estimation and reverted to eye-ball estimations. The present study generated a novel algorithm using multiple criteria to develop a robust predictive model for LW estimation of Ethiopian Menz sheep by using HG. Subsequently, recommended models currently in use in Ethiopia were evaluated for accuracy in predicting LW, using data of the present study. Liveweight and HG of 420 Menz sheep were measured. Simple linear model (SLM), Box–Cox (SLM with LW0.75), quadratic and allometric models were used to describe the relationship between LW and HG. Algorithms used to validate the models included data exploration, model construction and model redeployment. Results showed that all models had similar R2 (≈0.82). All models fitted the criteria of residual analysis and robustness against extreme values. However, only Box–Cox was robust against data redeployment, with 95th percentile of prediction error (PE) less than 10%. Accordingly, a Box–Cox model (LW0.75 = –9.71 + 0.289 (HG)) is robust and can be used to accurately predict LW of Menz sheep. The 95th percentile of PE of existing, recommended models was higher than 10; thus, they cannot be recommended to accurately predict LW of Menz sheep. The present study concludes that an approach based on regressing LW on HG, and then selecting models with the highest R2, is inadequate to generate accurate and robust prediction models. This highlights the importance of model redeployment to generate accurate prediction models. Calibrated HG bands are suitable alternatives to weighing scales in rural areas of Ethiopia because they are cheaper and not subject to maintenance. Thus, their accuracy and robustness in estimation of LW is vital for sustainable use.

Simple and robust algorithms to estimate liveweight in African smallholder cattle

Measurement of liveweight of stock is one of the most important production tools available to farmers – playing a role in nutrition, fertility management, health and marketing. Yet most farmers in sub-Saharan Africa do not have access to scales on which to weigh cattle. Heart girth measurements (and accompanying algorithms) have been used as a convenient and cost-effective alternative to scales, however despite a plethora of studies in the extant literature, the accuracy and sensitivity of such measures are not well described. Using three datasets from phenotypically and geographically diverse cattle populations, we developed and validated new algorithms with similar R2 to extant studies but lower errors of prediction over a full range of observed weights, than simple linear regression, that was valid for measurements in an unassociated animal population in sub-Saharan Africa. Our results further show that heart girth measurements are not sufficiently sensitive to accurately assess seasonal liveweight fluctuations in cattle and thus should not be relied on in situations where high precision is a critical consideration.

Proof of concept of faecal egg nematode counting as a practical means of veterinary engagement with planned livestock health management in a lower income country

BACKGROUND

The wellbeing and livelihood of farmers in impoverished regions of the world is intrinsically linked to the health and welfare of their livestock; hence improved animal health is a pragmatic component of poverty alleviation. Prerequisite knowledge and understanding of the animal health challenges facing cattle keepers in Malawi is constrained by the lack of veterinary infrastructure, which inevitably accompanies under-resourced rural development in a poor country.

METHODS

We collaborated with public and private paraveterinary services to locate 62 village Zebu calves and 60 dairy co-operative calves dispersed over a wide geographical area. All calves were visited twice about 2 to 3 weeks apart, when they were clinically examined and faecal samples were collected. The calves were treated with 7.5 mg/kg of a locally-available albendazole drench on the first visit, and pre- and post- treatment trichostrongyle and Toxocara faecal egg counts were performed using a modified McMaster method.

RESULTS

Our clinical findings point towards a generally poor level of animal health, implying a role of ticks and tick-transmitted diseases in village calves and need for improvement in neonatal calf husbandry in the dairy co-operative holdings. High faecal trichostrongyle egg counts were not intuitive, based on our interpretation of the animal management information that was provided. This shows the need for better understanding of nematode parasite epidemiology within the context of local husbandry and environmental conditions. The albendazole anthelmintic was effective against Toxocara, while efficacy against trichostrongyle nematodes was poor in both village and dairy co-operative calves, demonstrating the need for further research to inform sustainable drug use.

CONCLUSIONS

Here we describe the potential value of faecal nematode egg counting as a platform for communicating with and gaining access to cattle keepers and their animals, respectively, in southern Malawi, with the aim of providing informative background knowledge and understanding that may aid in the establishment of effective veterinary services in an under-resourced community.

Genome-wide association studies identified multiple genetic loci for body size at four growth stages in Chinese Holstein cattle

The growth and maturity of cattle body size affect not only feed efficiency, but also productivity and longevity. Dissecting the genetic architecture of body size is critical for cattle breeding to improve both efficiency and productivity. The volume and weight of body size are indicated by several measurements. Among them, Heart Girth (HG) and Hip Height (HH) are the most important traits. They are widely used as predictors of body weight (BW). Few association studies have been conducted for HG and HH in cattle focusing on single growth stage. In this study, we extended the Genome-wide association studies to a full spectrum of four growth stages (6-, 12-, 18-, and 24-months after birth) in Chinese Holstein heifers. The whole genomic single nucleotide polymorphisms (SNPs) were obtained from the Illumina BovineSNP50 v2 BeadChip genotyped on 3,325 individuals. Estimated breeding values (EBVs) were derived for both HG and HH at the four different ages and analyzed separately for GWAS by using the Fixed and random model Circuitous Probability Unification (FarmCPU) method. In total, 27 SNPs were identified to be significantly associated with HG and HH at different growth stages. We found 66 candidate genes located nearby the associated SNPs, including nine genes that were known as highly related to development and skeletal and muscular growth. In addition, biological function analysis was performed by Ingenuity Pathway Analysis and an interaction network related to development was obtained, which contained 16 genes out of the 66 candidates. The set of putative genes provided valuable resources and can help elucidate the genomic architecture and mechanisms underlying growth traits in dairy cattle.

Effects of anthelmintic treatment and feed supplementation on parasite infections and morbidity parameters in Cambodian cattle

Helminth infections are the cause of morbidity in Cambodian cattle but other factors such as nutritional deficiencies and concurrent diseases may enhance the effects of parasites. The present study aimed to investigate the impact of anthelmintic treatment, feed supplementation, or both on gastrointestinal strongyle (GIS) and trematode infections as well as on morbidity parameters in Cambodian village cattle. At the beginning of the dry season, cattle populations in six villages were randomly assigned to a group: (A) receiving anthelmintic treatment (ivermectin+clorsulon) at week 0; (P) feed pellet supplementation during week 0-13 or both (AP). On five visits (week 0-29), faecal and blood samples were obtained for parasitological examination and haematocrit determination, respectively. Body condition (BCS), hind quarter fouling (HQFS), diarrhoea (DS), and conjunctiva colour (FAMACHA^©) were scored and heart girth circumference was determined. To investigate the impact of treatment over time (week 0-29), a mixed model was used with treatment, time, and their interaction as fixed effects, and animal and village as random factors. At baseline, the proportion of GIS positive animals was high (67.9%), whereas trematode infections were low (Paramphistomum: 8.8%; Fasciola: 2.6%). Very thin to emaciated cattle (BCS 1-2) were more prevalent (11.4%) and FAMACHA^© scores of ≤3 or below (65.8%) less prevalent than in an earlier study in the region. A Time ⨯ Treatment interaction was present for faecal egg counts (FEC) of GIS, GIS prevalence (both p<0.0001), PCV (p=0.0034), DS (p=0.0086) and HQFS (p=0.0241). For GIS FEC, treatment groups differed at a specific time point, with levels of treatment group P being higher than in A at week 6 (p=0.0054). For Paramphistomum prevalence as well as FAMACHA^© scoring, heart girth and BCS, the interaction between treatment and time was not significant, yet, time in itself had a significant impact on all (p<0.0001). The beneficial effects of protein supplementation were unclear from the current study.

Use of body linear measurements to estimate liveweight of crossbred dairy cattle in smallholder farms in Kenya

Body linear measurements, and specifically heart girth (HG), have been shown to be useful predictors of cattle liveweight. To test the accuracy of body linear measurements for predicting liveweight, crossbred dairy cattle of different genotypes were measured and weighed. A total of 352 mature cows and 100 heifers were weighed using an electronic weighing scale and measurements of HG, body length, height at withers were taken using an ordinary measuring tape and body condition scored (BCS) using a five-point scale. The animals were grouped according to genotype and age. Genotype classification was undertaken from farmer recall and by visual appraisal as 40–60, 61–80 or 81–100 % exotic (non-indigenous). Age classification was simply as mature cows or heifers. Liveweight of the animals ranged from 102 to 433 kg. Liveweight was strongly correlated with HG (r = 0.84) and body condition scores (r = 0.70) and moderately correlated with body length (r = 0.64) and height at withers (0.61). Regressing LW on HG measurements gave statistically significant (P < 0.01) equations with R² ranging from of 0.53 to 0.78 and residual standard deviation ranging from 18.11 to 40.50 kg. The overall model developed (adjusted R² = 0.71) had a prediction error of 26 kg (or 11 % of the mean) and predicted LW of over 95 % of crossbred dairy cattle in the range of 100–450 kg, regardless of age and breed group. Including BCS in the model slightly improved the model fit but not the prediction error. It was concluded that the model can be useful in making general management decisions in smallholder farms.

Geographical assessment of body measurements and qualitative traits in West African cattle

A total of 1015 adult cows belonging to nine West African cattle breeds were assessed for 16 body measurements and 18 qualitative traits to ascertain the existence of geographical patterns of variation. Sampling was carried out in 29 different provinces of Mali, Burkina Faso and Benin. For body measurements, taurine breeds took lower average values than the zebu breeds. Sanga cattle took intermediate values. Qualitative traits did not allow to differentiate among cattle groups (taurine, zebu or sanga) or breeds. Principal component analysis identified two factors explaining 56.4 and 9.2 % of the variance for body measurements, respectively. Two correspondence analysis dimensions computed on qualitative traits explained a small proportion of the variability (20.8 and 13.5 %, respectively). Contour plots were constructed using the eigenvalues computed for each individual and either factor or dimension identified; confidence regions calculated confirmed that body measurements clearly differentiated zebu and taurine cattle breeds while qualitative traits did not. Factor 1 was projected on a geographical map, using provinces as nodes, to assess breed-free variation for body measurements. A pattern of continuous variation from the Sahel area southwards was identified. Probably, breeding decisions promoting the crosses between zebu-like and taurine cattle are underlying this geographical pattern of variation. The implementation of selection strategies aiming at the increase of the productivity of native West African taurine cattle breeds while avoiding looses in trypanotolerant ability would be highly advisable.

Diet composition, food intake, apparent digestibility, and body condition score of the captive Asian elephant (Elephas maximus): a pilot study in two collections in Thailand

Limited data are available regarding the nutrition and feeding of captive Asian elephants in range countries. In this study, feeding regimens of two collections in northern Thailand and their actual diets shaped by availability of forage and mahout preferences were assessed for nutritional quality. The composition of dietary intake, fecal output, and the dietary regimen were individually recorded for 5 days in 10 elephants. The proportion of forage in the diet represented 41 to 62% of the dry matter intake (DMI) in one collection whereas in the other collections it varied between 68 and 72%. Between 8.5 and 24% of the diet consisted of commercial pellets, and hulled rice represented up to 25% of the DMI in one collection. Sugar cane, corn cobs, and fruits such as bananas were eaten in smaller amounts. Body condition scores and weights were measured, which revealed that nine animals were in good condition. Representative samples of each food as well as fecal samples were analyzed for dry matter, crude protein, fat, crude fiber, gross energy, ash, calcium, and phosphorus. Diet adequacy was assessed by calculating the digestible nutrients in the rations and by comparing them to the recommendations from literature. The digestible energy (DE) intake varied between 0.6 and 1.4 megajoules (MJ) per kg(0.75) per day; therefore, higher than the estimated recommendations of 0.65 MJ per kg(0.75) per day for nine of the elephants. In all elephants the crude protein intake was less than the maintenance recommendations and ranged between 6.01 and 7.56% of the DMI. Calcium intake was low in one collection and there was an inverse calcium: phosphorus ratio, which was inadequate. The present study adds to the knowledge of captive elephant diets in Asia and is a starting point for further research, which is necessary to design optimum diet plans for captive Asian elephants in Thailand.