Effect of genetic and non genetic factors on first lactation traits in Gir cows

2016 ◽  
Author(s):  
Pushkraj Sawant ◽  
Basdev Singh ◽  
Dhruvaraj Sawant ◽  
Satya Prakash Yadav ◽  
Basant Kumar Bhinchhar
Keyword(s):  
Genetic Correlation ◽  
Milk Yield ◽  
Genetic Factors ◽  
Lactation Period ◽  
Dry Period ◽  
Phenotypic Correlations ◽  
Heritability Estimates

A total record of 113 Gir individuals spread over a period of 18 years from 1995 to 2012, were analyzed to estimate the effect of genetic and non genetic factors on first lactation period, first lactation milk yield and first dry period. The overall means for first lactation period (FLP), first lactation milk yield (FLMY) and first dry period (FDP), were 343.58± 10.37 days, 1664.95± 280.72 litres and 177.29± 10.59 days respectively. The heritability estimates for FLP, FLMY and FDP were 0.168± 0.238, 0.112± 0.252 and 0.419± 0.234 respectively. The genetic correlation between FLP and FLMY was positive and significant, while it was low and negative between FLP and FDP. The genetic correlation between FLMY and FDP was positive and highly significant. The phenotypic correlations between all traits were high and positive.

Factors affecting weight and age at first calving, first lactation milk yield in Gir cows

2016 ◽  
Author(s):  
Basdev Singh ◽  
Pushkraj Sawant ◽  
Dhruvaraj Sawant ◽  
Sachin Todkar ◽  
Richa Jain
Keyword(s):  
Genetic Correlation ◽  
Milk Yield ◽  
Dairy Farm ◽  
Madhya Pradesh ◽  
Age At First Calving ◽  
Factors Affecting ◽  
Phenotypic Correlations ◽  
Heritability Estimates

The present study was undertaken on data of 113 Gir cows maintained at Kasturba Gram Dairy Farm, Indore, Madhya Pradesh, India over a period of 18 years from 1995 to 2012, based on age at first calving. The overall means for weight at first calving (WFC), age at first calving (AFC), and first lactation milk yield (FLMY) were 402.22± 1.28 kg, 1709.04± 51.92 days and 1664.95± 280.72 litres respectively. The heritability estimates for WFC, AFC and FLMY were 0.248± 0.234, 0.307± 0.206 and 0.112± 0.252 respectively. The genetic correlation between WFC and AFC was positive and significant, while it was negative in between WFC and FLMY. The genetic correlation between AFC and FLMY was low and negative. The phenotypic correlations between all traits were positive.

scholarly journals Realized Sampling Variances of Estimates of Genetic Parameters and the Difference Between Genetic and Phenotypic Correlations

Genetics ◽  
1996 ◽  
Vol 143 (3) ◽  
pp. 1409-1416 ◽  
Author(s):  
Kenneth R Koots ◽  
John P Gibson
Keyword(s):  
Genetic Correlation ◽  
Genetic Parameters ◽  
Genetic Parameter ◽  
Genetic Correlations ◽  
Phenotypic Correlation ◽  
Parameter Estimates ◽  
Sampling Variance ◽  
Phenotypic Correlations ◽  
Genetic And Phenotypic Correlations ◽  
Heritability Estimates

Abstract A data set of 1572 heritability estimates and 1015 pairs of genetic and phenotypic correlation estimates, constructed from a survey of published beef cattle genetic parameter estimates, provided a rare opportunity to study realized sampling variances of genetic parameter estimates. The distribution of both heritability estimates and genetic correlation estimates, when plotted against estimated accuracy, was consistent with random error variance being some three times the sampling variance predicted from standard formulae. This result was consistent with the observation that the variance of estimates of heritabilities and genetic correlations between populations were about four times the predicted sampling variance, suggesting few real differences in genetic parameters between populations. Except where there was a strong biological or statistical expectation of a difference, there was little evidence for differences between genetic and phenotypic correlations for most trait combinations or for differences in genetic correlations between populations. These results suggest that, even for controlled populations, estimating genetic parameters specific to a given population is less useful than commonly believed. A serendipitous discovery was that, in the standard formula for theoretical standard error of a genetic correlation estimate, the heritabilities refer to the estimated values and not, as seems generally assumed, the true population values.

scholarly journals The use of dijkstra mechanistic model for genetic analysis of the lactation curve characteristics and their relationships with age at first calving and somatic cell score of Iranian dairy cows

2020 ◽  
Vol 42 ◽  
pp. e50181
Author(s):  
Mahdi Elahi Torshizi ◽  
Homayoun Farhangfar
Keyword(s):  
Somatic Cell ◽  
Genetic Correlation ◽  
Milk Yield ◽  
Mechanistic Model ◽  
Genetic Correlations ◽  
Somatic Cell Score ◽  
Specific Rate ◽  
Lactation Period ◽  
Age At First Calving ◽  
Lactation Curve

The objective of this study was to estimate lactation curve parameters with Dijkstra mechanistic model and to evaluate genetic and phenotypic relationships between the parameters and the average somatic cell count in primiparous cows. The finding indicated that heritability estimates for partial milk yield (PMY1, PMY2 and PMY3), total 305-day milk yield (TMY305), decay parameter (λ2), age at first calving (AFC) and peak yield (PY) were moderate while the heritability of persistency (PS%), average somatic cell score (AVGSCS), time to peak yield (TP), initial milk production (λ0), specific rate of cell proliferation at parturition (λ1), and specific rate of cell death (λ3) were quite low. Genetic correlations between both AFC and PS% traits with average somatic cell scores was negative (-0.047 and -0.060) but low positive genetic correlation were between partial milk yields (PMY1 and PMY3) while negative genetic correlation (-0.06) was obtained between TMY305 and AVGSCS. Differences between TMY305 of cows with less than 100000 cells mL-1 and cows with >1,500,000 cells mL-1 was approximately 708 Kg and is equivalent to 8% loss of milk yield/cow during lactation period and also loss of persistency (11.1 %( was shown for the extreme classes of SCC in this study.

RELATIONSHIPS OF REPRODUCTION TRAITS, BODY WEIGHT AND MILK YIELD IN DAIRY CATTLE

1986 ◽  
Vol 66 (1) ◽  
pp. 53-65 ◽  
Author(s):  
T. R. BATRA ◽  
A. J. LEE ◽  
A. J. McALLISTER
Keyword(s):  
Body Weight ◽  
Dairy Cattle ◽  
Milk Yield ◽  
Fixed Effects ◽  
Genetic Correlations ◽  
Calving Interval ◽  
Phenotypic Correlations ◽  
Reproduction Traits ◽  
Heritability Estimates ◽  
National Cooperative

The relationships between reproduction traits, body weight and milk yield were investigated using data from 1611 heifers and 733 cows from two lines of the National Cooperative Dairy Cattle Breeding Project. The data were analyzed separately for heifers and cows within lines using a mixed linear model containing fixed effects for station, year of birth, season of birth and random effect of sires. Heritability estimates and genetic correlations were estimated by a paternal half-sib analysis. Heritability estimates for heifer and cow reproduction traits ranged between 0 and 26% while those of body weights at calving and 112 d postpartum and milk yield ranged from 24 to 43%. Heifers with difficult calving had a higher incidence of retained placenta than those with normal calving. Phenotypic correlations between heifer reproduction traits and milk yield during first lactation were small. High milk production in cows was associated with longer calving interval. Phenotypic correlations between heifer's and cow's reproduction traits were small. Difficult calving in heifers impairs reproductive performance after calving resulting in greater number of days from calving to first and last breeding and leading to a longer calving interval. Key words: Reproduction traits, heifers, cows, milk yield, dairy cattle

Environmental and genetic factors affecting milk yield and quality in three Italian sheep breeds

2016 ◽  
Vol 84 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Maria Selvaggi ◽  
Angela Gabriella D'Alessandro ◽  
Cataldo Dario
Keyword(s):  
Milk Yield ◽  
Genetic Factors ◽  
Quality Traits ◽  
Milk Traits ◽  
Factors Affecting ◽  
Sheep Breeds ◽  
Lactation Length ◽  
Yield And Quality ◽  
Lack Of Information ◽  
Heritability Estimates

The aims of the study described in the Research Communication were to determine the level of influence of some environmental factors on milk yield and quality traits, including lactose, and lactation length in ewes belonging to three different Italian breeds and to estimate the heritability for the same traits. A total of 2138 lactation records obtained from 535 ewes belonging to three different Italian breeds (Comisana, Leccese, and Sarda) were used. Breed significantly affected all of the considered traits. Moreover, year of lambing affected milk yield and lactation length without influence on milk quality traits. Parity affected significantly only the milk yield, whereas type of birth showed its effect on milk yield, fat, protein, and lactose yield. On the whole, the presently reported heritability estimates are within the range of those already obtained in other dairy breeds by other authors, with values for lactation length being very low in all the investigated populations. Considering the heritability estimates for lactose content and yield, to the best of our knowledge, there is a lack of information on these parameters in ovine species and this is the first report on heritability of lactose content and yield in dairy sheep breeds. Our results suggest that genetic variability for milk traits other than lactation length is adequate for selection indicating a good response to selection in these breeds.

Effects of intramammary antibiotic therapy during the dry period on the performance of Lacaune dairy sheep under intensive management

2014 ◽  
Vol 82 (1) ◽  
pp. 95-101
Author(s):  
Fernando Hernandez ◽  
Laura Elvira ◽  
Beatriz Fernández ◽  
Marta Egea ◽  
Antonio Gonzalez-Bulnes ◽  
...  
Keyword(s):  
Milk Yield ◽  
Total Yield ◽  
Milk Quality ◽  
Control Group ◽  
Lactation Period ◽  
Intensive Management ◽  
Dairy Sheep ◽  
Dry Period ◽  
Antibiotic Group ◽  
Daily Milk Yield

Often the only way to ensure profitability of Lacaune dairy sheep is intensive management, which requires appropriate dry-period treatment to ensure animal productivity and health. The present study aimed to investigate the effects of intramammary antibiotic dry therapy on the performance and health of Lacaune sheep under intensive management. We recorded data for 5981 complete lactation periods that followed a dry period. A total of 2402 lactation periods were preceded by a dry period involving intramammary administration of 300 mg of cephapirin benzathine (antibiotic group) and 3579 lactation periods were preceded by dry periods with no treatment (control group). The following on-farm yield data were collected for individual lactation periods: length of the subsequent lactation period; total milk yield per lactation period; daily milk yield and length of the subsequent dry period. Data on confounding factors that might affect productivity were also recorded, including the individual ewe, number of lactation periods and length of the previous dry period. Milk quality was assessed using data on somatic cell count (SCC) and content of protein and fat taken from the Spanish National Official Milk Yield Recording System. Antibiotic dry therapy significantly improved total yield per lactation period, which was 429±151·1 l in the antibiotic group and 412±165·5 l in the control group, as well as the daily milk yield, which was 1986±497·0 and 1851±543·2 ml/d, respectively (both P<0·0001). The initial dry period was significantly longer in the antibiotic group than in the control group, and dry period length correlated inversely with yield variables such us total yield per lactation period (r=−0·055; P<0·0001) and yield per day in milk (r=−0·039; P<0·0001). As a result, milk yield records systematically underestimated the positive effects of antibiotic dry therapy. Antibiotic dry therapy also significantly improved milk quality. Milk from the antibiotic group showed 50% lower SCC (573±1326 vs. 1022±2126 cells/ml; P<0·0001) and slightly higher content in fat (7·33±0·91 vs. 7·15±0·87%) and protein (5·63±0·44 vs. 5·44±0·4%). The results of this study suggest that cephalosporin dry therapy of Lacaune dairy sheep increases milk production and improves milk quality during subsequent lactation periods.

The Gir cattle breed of India - characteristics and present status

2003 ◽  
Vol 33 ◽  
pp. 21-29 ◽  
Author(s):  
G.K. Gaur ◽  
S.N. Kaushik ◽  
R.C. Garg
Keyword(s):  
Body Weight ◽  
Milk Yield ◽  
Cattle Breed ◽  
The Body ◽  
Lactation Period ◽  
Cattle Population ◽  
Fat Percentage ◽  
Dry Period ◽  
Adult Body Weight ◽  
One Year

SummaryThe Gir is a famous milk cattle breed of India. The native tract of the breed is Gir hills and forests of Kathiawar including Junagadh, Bhavnagar, Rajkot and Amreli districts of Gujarat. The breeding tract lies between 20°5’ and 22°6’ north latitude and 70° and 72° east longitude. The total cattle population of Saurashtra region i.e., breeding tract of Gir cattle is 2.5 million and Gir breed accounts for 37 percent of total cattle population in the region. The body of Gir animals is well proportioned. Udder in cows is well developed and round. The body weight at one year of age was 138 kg in males and 136 kg in females. Adult body weight, height at withers, body length and heart girth in cows averaged 313 kg, 120 cm, 125 cm and 160 cm, respectively.Age at first heat and calving averaged 1 149 and 1 534 day, respectively. Average dry period and inter-calving period were 123 and 423 days, respectively. Heifers received an average 1.07 inseminations for successful conception whereas cows received 1.64 inseminations per conception. Total lactation milk yield averaged 2 063 litres in an average lactation period of 326 days. Average milk yield in 300 days was 1 930 litres. Milk yield per day of calving interval was 4.98 litres. Average fat percentage in the milk ranged between 4.69±0.04 and 4.97±0.02. Gir animals are considered as hardy with low overall mortality (3.63 percent).

Study of productive traits in Sahiwal x Holstein Friesian crossbred cows – Frieswal

2016 ◽  
Vol 50 (3) ◽  
Author(s):  
Basdev Singh ◽  
Pushkraj Sawant ◽  
Dhruvaraj Sawant ◽  
Gautam Dutt ◽  
Sachin Todkar
Keyword(s):  
Milk Yield ◽  
Significant Influence ◽  
Dairy Farm ◽  
Calving Interval ◽  
Lactation Period ◽  
Dry Period ◽  
Age At First Calving ◽  
Crossbred Cows ◽  
Holstein Friesian ◽  
Productive Traits

The present study was undertaken on data of 150 Frieswal cows (a new strain of Sahiwal x Holstein Friesian) maintained at Military Dairy Farm, Agra, over a period of 15 years from 1996-2010, based on age at first calving. The overall means for age at first calving (AFC), weight at first calving (WFC), first lactation milk yield (FLMY), first lactation period (FLP), first dry period (FDP) and first calving interval (FCI) were 928.07±0.08 days, 369.87±0.92 kg, 4054.35±22.14 litres, 301.84±0.26 days, 99.40±0.15 days and 401.33±0.33 days respectively. The period of calving has significant influence on AFC and WFC, whereas non-significant influence on FLMY, FLP and FDP. The season showed significant influence on all the traits under study except FLMY. Both period and season has highly significant influence on FCI.

Environment and genetic factors affecting wool production from sub-tropical coarse wool sheep

1977 ◽  
Vol 88 (2) ◽  
pp. 443-447 ◽  
Author(s):  
A. M. Aboul-Naga ◽  
E. A. Afifi
Keyword(s):  
Genetic Correlation ◽  
Reproductive Performance ◽  
Genetic Parameters ◽  
Genetic Factors ◽  
Factors Affecting ◽  
Wool Production ◽  
Body Weights ◽  
Performance Traits ◽  
Heritability Estimates ◽  
Fleece Weight

SUMMARYWool production from different flocks of Ossimi, Rahmani and Barki Egyptian local sheep, raised at six different locations in the country was studied. Different genetic parameters for greasy fleece weight of the three breeds were estimated.Location was of significant effect on annual greasy fleece weight of Rahmani sheep only. With the adjustment for differences in yield percentages, differences in clean wool production from one location to another were slight for the three breeds. Age of ewe was of highly significant effect on annual greasy fleece weight.Heritability estimates of annual greasy fleece weight of the ewes were found to be generally low in the three breeds (range 0·00–0·34). The estimates differed markedly with age; those of the yearling fleece weight of Rahmani and Barki ewes were the highest, being 0–19 and 0–34, respectively.Repeatability estimates of annual greasy fleece weight were also low, being 0·11–0·04 and 0·29 for Ossimi, Rahmani and Barki ewes, respectively.Estimates of genetic correlation between yearling greasy fleece weight of the Ossimi and Rahmani ewes and their weaning and yearling body weights were high and positive. Those between annual greasy fleece weight of the ewes and their reproductive performance traits differed greatly in the two breeds.

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