Genetic factors affecting the milk intake of lambs

1966 ◽  
Vol 17 (2) ◽  
pp. 191 ◽  
Author(s):  
RW Moore
Keyword(s):  
Milk Production ◽  
Genetic Factors ◽  
Milk Intake ◽  
The Other ◽  
Relative Importance ◽  
Factors Affecting ◽  
Actual Amount ◽  
Genotype Effects

The actual amount of milk produced by a ewe is influenced both by her own potential to produce milk and by the potential of the lamb to obtain it. Two experiments were carried out to investigate the relative importance of these factors. In each experiment there were two genetically different groups of ewes, of which some reared their own single lambs and some reared single lambs from the other group fostered onto them. In both experiments, the effect of the genotype of the lamb was greater than that of the ewe. In the first experiment, during the period 6–24 days after parturition, ewes suckling strong-wool lambs produced 7.2 g/hr more milk than those suckling Peppin lambs, while the strong-wool ewes themselves produced only 4.6 g/hr more than the Peppin ewes. In the second experiment, during the period 0–28 days after parturition, ewes suckling Corriedale lambs produced 11.6 g/hr more milk than those suckling strong-wool Merino lambs, whereas the Corriedale ewes themselves produced only 4.4 g/hr more than the strong-wool Merino ewes. The lamb genotype effects were statistically significant. In a third experiment, in which the strong-wool and medium-wool Merinos were compared when suckling twins, the strong-wool exceeded the medium by 10.8 g/hr in milk production for the period 6-24 days after parturition. Some implications of the results are discussed.

scholarly journals THE FACTORS AFFECTING MILK YIELD IN DIARY FARMING IN GREATER GUWAHATI REGION OF ASSAM

2021 ◽  
Vol 9 (08) ◽  
pp. 723-728
Author(s):  
Heman Sarmah ◽  
◽  
Jnanashree Borah ◽  
Tirthankar Sarma ◽  
◽  
...  
Keyword(s):  
Regression Analysis ◽  
Dairy Cattle ◽  
Milk Production ◽  
Milk Yield ◽  
Policy Maker ◽  
Production Cost ◽  
Relative Importance ◽  
Factors Affecting ◽  
Micro Level ◽  
Farming Households

The production of milk is conceived of several factors and a very multifarious process. The knowledge of relative importance of the resource inputs influencing in milk production is essential for the dairy farmer for introducing desirable change in his operation at micro level and for the policy maker for formulating plans for improvements in dairy cattle productivity based on sound economic principles at the macro level (Rao, 1985).The income level of the dairy household is determined by the production of milk they produce at their farms. Generally, the income of the dairy household increases when the milk production cost decreases or when the milk production increases .For this it is essential to study the factors which directly or indirectly effect the milk production. Household samples have been selected both from the municipal wards of Guwahati Municipal Corporation area. Out of 672 dairy farming households, 201 household have been selected for the survey. Regression analysis has been used for the study of factors affecting milk production in greater Guwahati region of Assam.

Factors affecting first lactation cumulative monthlymilk yields in Frieswal cattle

2016 ◽  
Author(s):  
SPACE Rajeev ◽  
Rajbir Singh ◽  
Ravinder Kumar ◽  
T. V. Raja ◽  
Y. P. Singh Nazim Ali ◽  
...  
Keyword(s):  
Least Squares ◽  
Total Variation ◽  
Milk Production ◽  
Rainy Season ◽  
Genetic Selection ◽  
Dairy Farm ◽  
The Other ◽  
Factors Affecting ◽  
Selection Programme

A study was conducted to analyse the effect of various factors on cumulative monthly milk yields in Frieswal cows at Military Dairy Farm, Meerut, over a period of eight years (2006-2013). A total of 441 part lactation records of cows born to 30 Frieswal sires were analyzed using the SAS (2002) software. The least squares’ model developed for the cumulative 30, 60, 90, 120, 150, 180, 210, 240, 270 and 300 days yields accounted for 13.5, 13.5, 12.8, 12.0, 11.5, 11.6, 11.3, 10.3, 13.7 and 13.7 per cent of the total variation, respectively. The overall least squares’ averages for the cumulative 30, 60, 90, 120, 150, 180, 210, 240, 270 and 300 days of first lactation yields were estimated as 313.29, 660.83, 998.19, 1321.58, 1627.06, 1916.78, 2201.26, 2445.01, 2741.04 and 2972.64 kg, respectively. The effects of sire, season and period of calving were found to be statistically non-significant on any of the cumulative monthly part lactation yields while the regression of monthly part yields on AFC was found to be highly significant (P<0.01). Based on the results it was concluded that the AFC was the most significant factor which alters the cumulative part lactation yields in Frieswal cattle while the other factors like sire of cows, season and period of calving did not alter the part yields significantly. The cows calved during rainy season produce comparatively higher yield followed by summer and winter calvers. It may also be concluded that the genetic selection programme implemented in the Frieswal project resulted in increasing the milk production over the years of study.

Variation in susceptibility of inbred lines of chickens to seven species ofEimeria

Parasitology ◽  
1992 ◽  
Vol 104 (3) ◽  
pp. 407-413 ◽  
Author(s):  
N. Bumstead ◽  
B. J. Millard
Keyword(s):  
Inverse Relationship ◽  
Genetic Factors ◽  
Developmental Stages ◽  
Inbred Lines ◽  
The Other ◽  
Factors Affecting

The pattern of oocyst production of 8 inbred lines of chickens was compared for each of the 7 species ofEimeriawhich infect this host. Both the overall numbers and the pattern of oocyst production differed in the inbred lines, but there was no evidence of prolonged cycling of schizogenic developmental stages. Comparison of the numbers of oocysts produced by the different lines indicates that there may be common genetic factors affecting susceptibility to 6 of the 7 species. Surprisingly there appears to be an inverse relationship between susceptibility toE. tenellaand susceptibility to the other species: lines which produced most oocysts ofE. tenellaproduced least oocysts of the other species andvice-versa.

scholarly journals Factors Affecting Lactation Performance of Deoni Cattle

2020 ◽  
Vol 15 (04) ◽  
pp. 59-61
Author(s):  
Supriya G ◽  
Prashant Waghmare ◽  
Vivek Patil ◽  
Prakashkumar Rathod ◽  
Vidyasagar .
Keyword(s):  
Milk Yield ◽  
Genetic Factors ◽  
The Other ◽  
Age Group ◽  
Lactation Performance ◽  
Factors Affecting ◽  
Lactation Length ◽  
Performance Traits ◽  
Effect Of Age

The research was conducted on 78 lactation records of 78 Deoni cows over three years to analyze the effect of non-genetic factors on lactation performance traits. Data of lactation records were analyzed to determine the effect of age, parity, a period of calving and season of calving on lactation traits, viz., lactation milk yield (LMY), peak milk yield (PMY), lactation length (LL) and persistency of lactation. The findings revealed that age group and parity had a significant (p ≤0.05) effect on lactation milk yield, but not the period of calving and season of calving. Further, only the parity had a significant (P≤0.05) effect on peak milk yield of Deoni cattle but not the age group, period of calving, and season of calving. The other two traits, namely lactation length, and persistence was not influenced significantly by any the non-genetic factors evaluated in Deoni cattle.

I.—Genetics of Gametes. I. A Quantitative Analysis of Five Characteristics of Rabbit Spermatozoa

1961 ◽  
Vol 68 (1) ◽  
pp. 1-16
Author(s):  
R. A. Beatty ◽  
R. A. N. Napier
Keyword(s):  
Genetic Factors ◽  
Vas Deferens ◽  
Average Length ◽  
Mammalian Species ◽  
Relative Importance ◽  
Factors Affecting ◽  
Statistical Procedures ◽  
Quantitative Form ◽  
Rabbit Spermatozoa ◽  
Mammalian Spermatozoa

SynopsisInformation is presented on some ways in which spermatozoa vary within a mammalian species, and on the relative importance of non-genetic factors affecting this variation. The work is basic to current researches in this laboratory on the genetics of mammalian spermatozoa. Five characteristics of rabbit spermatozoa were examined in permanent nigrosin-eosin preparations: the incidence of stained spermatozoa and the incidence of spermatozoa lacking the acrosomal cap, both related to the fertility of semen; the length, breadth and area of the spermatozoan head. Various factors have been studied that potentially affect these characteristics, with emphasis on variation attributable to technique and observation. The effects of the factors have been recorded in quantitative form and, in the light of the present work, suggestions have been made for the design of future experiments. Experimental and statistical procedures are described. Observations on variation due to biological causes include a separation of the variance between the males of a litter from the variance between the litter means. It has also been shown that the average length of the spermatozoan head in the vas deferens remains virtually unchanged in the ejaculate. Mensuration characteristics (length, breadth and area) are better adapted to objective analysis than are enumeration characteristics (proportions of abnormal spermatozoa).

A review of the genetic and non-genetic factors affecting extended lactation in pasture-based dairy systems

2015 ◽  
Vol 55 (8) ◽  
pp. 949 ◽  
Author(s):  
Mary Abdelsayed ◽  
Peter C. Thomson ◽  
Herman W. Raadsma
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Genetic Factors ◽  
Genetic Selection ◽  
Factors Affecting ◽  
Environmental Interactions ◽  
Holstein Friesian ◽  
Component Traits ◽  
Dairy Systems ◽  
Extended Lactation

Milk production per cow has significantly increased over the last 50 years due to the strong genetic selection for increased milk production; associated with this increased production has been a decline in reproductive performance. As a result, superior-yielding cows that have failed to get into calf in a traditional 12-month calving system may be carried over and milked continuously for another 6 months instead of being culled. Studies indicate that cows are able to achieve lactations greater than 305 days and up to 670 days under pasture-based systems, with and without the use of supplementary feeds. Extended lactations of 16 months are most common and economically viable in Australian dairy systems. These findings indicate a potential role for extended lactation in countries such as Australia, where pasture-based dairy systems in which Holstein-Friesian dairy cows predominate. However, variation between cows in their milk yield profiles and the ability of cows to reach a planned dry-off date over an extended lactation occurs depending on the cow’s genetic strain, nutrition and environmental interactions, with certain strains of cow being better suited to extended lactation than others. The focus of this review is to examine the scope for genetic improvement as well as important considerations (non-genetic factors) when selecting suitable animals for extended lactation in pasture-based dairy systems, with an emphasis on Australian systems. These considerations include the impacts of cow strain, nutrition, milk production, and biological and economical costs associated with extended lactation. Methods for modelling extended lactation and estimating genetic parameters of lactation persistency, milk yield and component traits under extended lactation will be addressed and future directions for further research suggested.

scholarly journals The Major Driving Factors of Carbon Emissions in China and Their Relative Importance: An Application of the LASSO Model

2021 ◽  
Vol 9 ◽  
Author(s):  
Wai Yan Shum ◽  
Ning Ma ◽  
Xiaomei Lin ◽  
Tingting Han
Keyword(s):  
Economic Growth ◽  
Carbon Emissions ◽  
The Other ◽  
Income Growth ◽  
Relative Importance ◽  
Policy Makers ◽  
Factors Affecting ◽  
Independent Variables ◽  
Policy Interventions ◽  
The World

China is one of the biggest energy consumers and carbon emitters in the world. Understanding the factors affecting carbon emissions is critical for policymakers to control the rising trend of carbon emissions. This paper investigates the relative importance of carbon emissions drivers in China. Literature review has been carried out to determine a set of predominant independent variables; the LASSO model is then introduced to rank the relative importance among the set of independent variables. The results find that 1) carbon emissions were mainly driven by economic growth and energy consumption followed by population size and industrialization; and 2) income growth slowed down carbon emissions during the studied period, but it is the least significant factor among the other factors. The ranking allows policy makers to focus on the most critical contributors to carbon emissions and gives policymakers more flexibility in determining policy interventions.

Ethnicity and Sex Ratio in Twin Births

1991 ◽  
Vol 40 (3-4) ◽  
pp. 311-317 ◽  
Author(s):  
R. Picard ◽  
D. Fraser ◽  
E. Picard
Keyword(s):  
Sex Ratio ◽  
Maternal Age ◽  
Genetic Factors ◽  
Reproductive Factors ◽  
The Other ◽  
Relative Importance ◽  
Inverse Effect ◽  
High Level ◽  
Male Twin ◽  
Continue Monitoring

AbstractThe patterns of sex ratio in Israeli twins by maternal age and parity are described in two ethnic subpopulation. Jews and Bedouins differ one from the other in genetic, environmental, lifestyle, and reproductive factors. In the Jewish subpopulation, the proportion of males was significantly lower in twin than in singleton births; parity increased the odds of male twin births while maternal age had the inverse effect. In the Bedouin subpopulation, the sex ratio did not differ significantly from that of singletons, and no consistent patterns were found by maternal age and parity. The data suggest that several factors may influence the sex ratio in twin births. In Jewish twin births, the findings are consistent with the literature and can be largely explained in terms of high level of maternal gonadotropins. In the Bedouin subpopulation, paternal influence which could be related to lifestyle may be present, and as yet undefined genetic factors may also be involved. It would be of great interest, therefore, to continue monitoring of the effects of changes in lifestyle on the Bedouin population in order to tease out the relative importance of the varying factors on the sex ratio of twin births.

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