RUMINANT LIVESTOCK GENETIC RESOURCES IN CYPRUS

1985 ◽  
Vol 4 ◽  
pp. 1-8 ◽  
Author(s):  
A. Constantinou
Keyword(s):  
Genetic Resources ◽  
Litter Size ◽  
Milk Yield ◽  
Meat Production ◽  
Specific Strain ◽  
Indigenous Goat ◽  
Chios Sheep ◽  
Friesian Cattle ◽  
Ruminant Livestock

SUMMARYFriesian cattle, Chios sheep and Damascus goats have become dominant livestock breeds in Cyprus. Chios sheep were found to be superior to the indigenous Cyprus FatTailed and the imported Awassi with respect to precocity, fertility and prolificacy. Awassi performed very well with regard to milk yield and lamb viability. Crossbreds were more or less intermediate. Crosses of Chios with Cyprus Fat-Tailed have contributed substantially to the improvement of milk and meat production from sheep in the country.Damascus goats are very good in litter size and milk yield; a specific strain of the indigenous goat also appears to be a valuable genotype.

NEURAL FACTORS IN THE MAINTENANCE OF LACTATION IN THE RAT

1967 ◽  
Vol 38 (1) ◽  
pp. 51-59 ◽  
Author(s):  
J. A. EDWARDSON ◽  
J. T. EAYRS
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Quantitative Relationship ◽  
Mammary Tissue ◽  
Single Pair ◽  
Endocrine Response ◽  
Peripheral Innervation ◽  
Lactational Performance ◽  
Neural Factors

SUMMARY The role of the peripheral innervation of mammary tissue in the maintenance of lactation has been investigated by the procedure of selective thelectomy combined with denervation of the posterior thoracic nipples. When suckling is restricted to a single pair of nipples bilateral transection of the three adjacent nerves supplying a nipple arrests lactation completely; partial denervation is associated with a reduced level of lactational performance which is directly related to the concentration of the residual innervation. Increase in litter size is associated with an overall increase in milk-yield up to a limit beyond which the addition of further young to the litter is without effect. It is inferred that there is a quantitative relationship between the neural stimulus of suckling and the endocrine response of the hypothalamopituitary system.

scholarly journals Whole Genome Sequencing Reveals the Effects of Recent Artificial Selection on Litter Size of Bamei Mutton Sheep

Animals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 157
Author(s):  
Yaxin Yao ◽  
Zhangyuan Pan ◽  
Ran Di ◽  
Qiuyue Liu ◽  
Wenping Hu ◽  
...  
Keyword(s):  
Candidate Genes ◽  
Litter Size ◽  
Artificial Selection ◽  
Estrogen Signaling ◽  
Meat Production ◽  
Domestic Sheep ◽  
Whole Genome ◽  
Nonsynonymous Mutation ◽  
Demethylase Activity ◽  
Mongolian Sheep

Bamei mutton sheep is a Chinese domestic sheep breed developed by crossing German Mutton Merino sheep and indigenous Mongolian sheep for meat production. Here, we focused on detecting candidate genes associated with the increasing of the litter size in this breeds under recent artificial selection to improve the efficiency of mutton production. We selected five high- and five low-fecundity Bamei mutton sheep for whole-genome resequencing to identify candidate genes for sheep prolificacy. We used the FST and XP-EHH statistical approach to detect the selective sweeps between these two groups. Combining the two selective sweep methods, the reproduction-related genes JUN, ITPR3, PLCB2, HERC5, and KDM4B were detected. JUN, ITPR3, and PLCB2 play vital roles in GnRH (gonadotropin-releasing hormone), oxytocin, and estrogen signaling pathway. Moreover, KDM4B, which had the highest FST value, exhibits demethylase activity. It can affect reproduction by binding the promoters of estrogen-regulated genes, such as FOXA1 (forkhead box A1) and ESR1 (estrogen receptor 1). Notably, one nonsynonymous mutation (p.S936A) specific to the high-prolificacy group was identified at the TUDOR domain of KDM4B. These observations provide a new opportunity to research the genetic variation influencing fecundity traits within a population evolving under artificial selection. The identified genomic regions that are responsible for litter size can in turn be used for further selection.

scholarly journals Effects of month of kidding, parity number, and litter size on milk yield of commercial dairy goats in Australia

2020 ◽  
Vol 103 (1) ◽  
pp. 954-964 ◽  
Author(s):  
F. Zamuner ◽  
K. DiGiacomo ◽  
A.W.N. Cameron ◽  
B.J. Leury
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Dairy Goats ◽  
Parity Number

scholarly journals Milk Production of Lacaune Sheep with Different Degrees of Crossing with Manchega Sheep in a Commercial Flock in Spain

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 520
Author(s):  
Lizbeth E. Robles Jimenez ◽  
Juan C. Angeles Hernandez ◽  
Carlos Palacios ◽  
José A. Abecia ◽  
Anna Naranjo ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Milk Production ◽  
Litter Size ◽  
Milk Yield ◽  
Mixed Model ◽  
The Other ◽  
Commercial Flock ◽  
Parity Number ◽  
Available Information ◽  
Autumn And Winter

The objective of the present study was to evaluate the effect of the grade of crossbreeding (Lacaune x Manchega) and environmental factors on milk production in a commercial flock in Spain. A total of 5769 milk production records of sheep with different degrees of purity of the Lacaune breed crossed with Manchega were used as follows: 100% Lacaune (n = 2960), 7/8 Lacaune (n = 502), 13/16 Lacaune (n = 306), 3/4 (n = 1288), 5/8 Lacaune (n = 441) and 1/2 Lacaune: Manchega (n = 272). Additional available information included the number of parity (1 to 8), litter size (single or multiple), and the season of the year of lambing (spring, summer, autumn and winter). A mixed model was used to evaluate the level of crossbreeding and environmental factors on milk production. The 100% Lacaune sheep presented the highest milk production with respect to the F1 Lacaune x Manchega sheep (p < 0.01), showing that as the degree of gene absorption increases with the Manchega breed, it presents lower milk yield. The 100%, 13/16, and 3/4 Lacaune genotypes had the highest milk yields with respect to the 1/2 Lacaune/Manchega breed (p < 0.001). The Lacaune registered on average 181.1 L in a period adjusted to 160 days of lactation (1.13 L/ day). Likewise, the parity number, litter size, and season of lambing effects showed significant differences (p < 0.01). It was concluded that 13/16 and 3/4 Lacaune/Manchega ewes presented the highest milk yields with respect to the other crosses.

Relationships among udder type traits and milk yield of Iranian Holstein-Friesian cattle

2003 ◽  
Vol 2003 ◽  
pp. 141-141
Author(s):  
M. R. Sanjabi ◽  
M. G. Govindaiah ◽  
M. M. Moeini
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Genetic Correlations ◽  
Holstein Friesian ◽  
Type Traits ◽  
High Production ◽  
Friesian Cattle

Correlation among type traits and with milk production has been investigated by Brotherstone (1994) and Misztal et al (1992). One of the primary reasons for collecting and utilizing information on type traits is to aid breeders in selecting profitable functional cows for high production and suitable herd life. The objectives of this study were to estimate phenotypic and genetic correlations among milk production and with udder traits.

scholarly journals Covariance components by a repeatability model in Slovenian dairy sheep using test-day records

2009 ◽  
Vol 54 (No. 9) ◽  
pp. 426-434 ◽  
Author(s):  
A. Komprej ◽  
G. Gorjanc ◽  
D. Kon ◽  
M. Kovač
Keyword(s):  
Protein Content ◽  
Litter Size ◽  
Milk Yield ◽  
Genetic Correlations ◽  
Dairy Sheep ◽  
Milk Traits ◽  
Environment Effect ◽  
Covariance Components ◽  
Daily Milk Yield ◽  
Daily Milk

The estimation of covariance components for daily milk yield, fat and protein content was performed in three Slovenian dairy sheep breeds (Bovec, Improved Bovec, and Istrian Pramenka). In the period 1994–2002, 38 983 test-day records of 3 068 ewes were collected according to ICAR regulations (method A4). All the available relationships between animals were considered. For that reason, information on 3 534 animals was included. Test-day records were analysed by a multiple-trait repeatability animal model. In its fixed part, the model contained breed and season of lambing as classes. Days after lambing, parity, and litter size were treated as covariates. Days after lambing were modelled with modified Ali-Schaeffer’s lactation curve, parity with quadratic, and litter size with linear regression. The random part of the model consisted of flock-test month effect, additive genetic effect, permanent environment effect over lactations, and permanent environment effect within lactation. Covariance components were estimated using the restricted maximum likelihood method (REML). The estimated heritabilities were 0.11 for daily milk yield, 0.08 for fat content, and 0.10 for protein content. A relatively high variance ratio for all milk traits was explained by the flock-test month effect (from 0.27 for daily milk yield to 0.57 for protein content), while ratios explained by both permanent environment effects were lower (up to 0.13). Additive genetic correlations between daily milk yield and fat content, and daily milk yield and protein content were negative and similar (–0.36 and –0.37). A high and positive (0.67) additive genetic correlation between fat and protein content was found. Correlations for environmental effects showed a pattern similar to additive genetic correlations. Genetic parameters estimated in Slovenian dairy sheep showed that genetic progress in milk traits could be achieved using test-day milk records.

scholarly journals Changes in Milk Yield and Quality During Lactation in Polish Red and White-Backed Cows Included in the Genetic Resources Conservation Programme in Comparison with the Simmental Breed

2016 ◽  
Vol 16 (3) ◽  
pp. 871-886 ◽  
Author(s):  
Zygmunt Litwińczuk ◽  
Joanna Barłowska ◽  
Alicja Matwijczuk ◽  
Jan Słomiany
Keyword(s):  
Phase I ◽  
Genetic Resources ◽  
Milk Yield ◽  
Dry Matter ◽  
Reference Group ◽  
Low Input ◽  
Milk Samples ◽  
Fat Globules ◽  
Yield And Quality ◽  
Resources Conservation

AbstractMilk yield and quality was assessed in cows raised on low-input farms (traditional feeding), i.e. two breeds covered by genetic resources conservation (RP and BG) and the SM breed. The reference group was PHF HO cows from an intensive milk production system (PMR feeding). A total of 1,212 milk samples were collected from three periods of lactation: I (up to 120 days), II (121–200) and II (over 200). The milk was analysed for content of fat, protein, casein, lactose, dry matter, non-fat dry matter and the protein-to-fat ratio, coagulation time, heat stability and the percentage of fat globules in different size ranges. Fatty acid profile and cholesterol content were determined in a representative number of 180 milk samples. Daily yield in the native breeds in the third phase of lactation was 9.6 and 8.7 kg, which was slightly over 55% of their yield in phase I, compared to 66% in the SM and 73.4% in the reference group (PHF HO). The increase in fat and protein (including casein) in the milk during lactation was much higher in the native breeds, so its energy value in phase II of lactation was 11% higher in the BG cows and 9% higher in RP, but only 4% higher in the SM with regard to phase I of lactation. The milk fat from the Polish Red cows had the highest proportion of PUFA in each phase of lactation, including CLA, and the highest PUFA/SFA ratio. Over the course of lactation the percentage of large fat globules in the milk decreased, particularly in the native breeds (P≤0.01), while in the SM the differences were much smaller and statistically insignificant. Lactation persistency in both native breeds raised in a low-input system was worse than in the SM, but the increase in basic components during lactation was markedly higher, while that of cholesterol was lower.

The biological efficiency of meat production in sheep

1970 ◽  
Vol 12 (3) ◽  
pp. 393-401 ◽  
Author(s):  
R. V. Large
Keyword(s):  
Growth Rate ◽  
Litter Size ◽  
High Growth ◽  
High Growth Rate ◽  
Biological Efficiency ◽  
Meat Production ◽  
Final Size ◽  
Artificial Rearing ◽  
Factors Affecting ◽  
Digestible Organic Matter

SUMMARYThe biological efficiency of meat production (E) is defined as the weight of carcass produced per 100 units of digestible organic matter (DOM) consumed. The factors affecting this relationship, for ewes and lambs, are discussed and the results of experiments are used to demonstrate the effect of number of lambs per year and size of ewe on the value of E. Calculations are made to show the effect on E of other factors such as the growth rate of the lambs and the weight at which the lambs are slaughtered. The general conclusions are that the highest values for E will be obtained from small breeds of ewes producing large litters and crossed with a large breed of ram, leading to a high growth rate and final size in the lamb. A relatively small increase in litter size in the small breeds of ewe (i.e. from one to two lambs) may result in a level of efficiency as high as that achieved by a larger breed with a large litter size (i.e. three to four lambs) without having to resort to techniques such as the artificial rearing of lambs.

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