DOI: 10.5281/zenodo.8146296
title: Database of average values of parameters of sire rams of Latvian dark-head breed calculated from values of intensive fattening lambs within the framework of the project of the Latvian Council of Science LZP-2021/1-0489 project

description: Project of The Latvian Council of Science (LCS) - LZP-2021/1-0489 project: “Development of an innovative approach to identify biological determinants involved in the between-animal variation in feed efficiency in sheep farming.”


The aim of the project is to determine whether the feed efficiency status of Latvian meat sheep breeds could be predicted using a panel of genetic and molecular markers previously found to be associated with divergent Feed efficiency status in a training population of lambs when fed the same diet.


Novelty: to determine the parameters predicting the most productive result of lamb rearing, we set out to develop the cheapest and most effective method for determining markers of feed efficiency - based on molecular and genetic markers obtained from the blood of live lambs.


About the project:


The costs associated with lambing (buying or keeping sheep) and preparing or purchasing feed are the two largest components of variable costs in sheep raising. Feed costs are high due to poor grain growing conditions in major producing countries, the use of feed grains in ethanol production, and increased competition for land in crop production compared to urban development. Feed efficiency in growing lambs (i.e., the animal's ability to reach a market or adult body weight (BW) with the least amount of feed intake), is a key factor in the sheep industry. Improving Feed efficiency reduces production costs. Improving Feed efficiency by 5% can bring economic benefits that are up to four times higher than a 5% increase in average daily gain (ADG).


Traditionally, meat breeding programs have focused on outputs due mainly to the routine availability of phenotypic data on outputs or correlated traits. Currently, no marker has successfully explained enough of the variability in feed efficiency that they were used as part of a routine improvement program, as well as according to our data, no genetic parameters for performance and feed efficiency traits are available for sheep. The physiological determinants of feed efficiency or putative biomarkers used to analyze animal-to-animal variation in live lambs could be used as a cost-effective and rapid tool for genetic selection or management decisions.


As of 2018, there were 49.5 thousand ewes and 73 sire rams in Latvia from a flock of 134.29K sheep. In 2018, Latvian Dark-Head (Latvijas tumšgalve; LT) sheep were bred to implement the sheep breeding program in 35 farms, which had a total of 3,752 ewes, while 13 farms had 43 breeding rams. According to the EUROSTAT data, the number of sheep in Latvia in 2018 was 107.29K, but in December 2021 was 90.34K.


The Latvian Dark-Head sheep breed was created by crossing local Latvian sheep with Shropshire and Oxfordshire rams imported from Sweden and England. The first pedigree or breeder's book for LT rams was issued in 1939. Currently, the live weight of ewes of the Latvian Dark-Head breed is about 55 – 65 kg, rams - 95 – 120 kg, wool cut 3.5 – 4.5 and 5.0 – 6.0 kg, respectively. The average prolificacy of ewes is 150 - 160%.


Breeding of Latvian Dark-Head sheep in Latvia is carried out according to phenotypic and bloodline data, without information about values of feed efficiency indicators or carrying out genetic breeding. Therefore, this study aimed to analyze the Latvian Dark-Head breeds rams according to lambs' feed efficiency values.


About the data of the project:


LZP-2021/1-0489 project data on Latvian dark-head (LT; Latvijas tumšgalve) of the year 2022 lamb samples, or A22_LT group. In the group were 48 lambs from 13 sire rams.


Based on the requirements of the breeding program of the breeds, every year, the offspring of the sire ram, certified for breeding activity, are selected and analyzed to estimate the sire rams. All lambs were born as twins, triplets or quadruplets from different ewes and health status was assessed prior to inclusion in the study so that there were at least two lambs per sire ram from the breed. This study was carried out in cooperation with Latvian Sheep Breeders' Association at the ram breeding control station.


The dataset includes average data of each sire ram: (1) ultrasonography measurements of lambs during the beginning and end of fattening, (2) intensive fattening data - real and calculated on the 90th and 150th day, (3) the amount of feed used, (4) slaughter data, (5) biochemical indicators: Insulin-like growth factor 1, Insulin, Total thyroxine, Adrenocorticotropic hormone, Haematocrit, Hemoglobin, Glucose, (6) feed efficiency indicators: Feed efficiency (FE), Feed conversion ratio (FCR), Relative growth rate (RGR), Kleiber’s ratio (KR), Residual feed intake (RFI), Residual weight gain (RWG) and Residual intake and body weight gain (RIG).


 


The data is the joint property of the participants of the LCS project: the University of Latvia and the Latvian University of Life Sciences and Technologies.
description: The obtained results have been published: I. Trapina, D. Kairisa, N. Paramonova. Comparison of sire rams of the Latvian Dark-Head breed according to feed efficiency indicators as the beginning of genomic breeding research. Agronomy Research, 21(S2), 598–610, 2023. https://doi.org/10.15159/ar.23.030.