The effect of environment and heredity on lactation. II. Persistency of lactation

1951 ◽  
Vol 41 (1-2) ◽  
pp. 89-93 ◽  
Author(s):  
P. Mahadevan
Keyword(s):  
Milk Yield ◽  
Statistical Study ◽  
Total Production ◽  
Present Material ◽  
Factors Affecting ◽  
South West ◽  
Lactation Curve ◽  
Numerical Expression

1. A statistical study of factors affecting variation in persistency of lactation has been made using 5000 lactation records from twelve leading herds of Ayrshire cattle in south-west Scotland for the period 1930–9.2. It is suggested that a satisfactory numerical expression for the shape of the lactation curve could be obtained from the formula, Persistency = where A is the milk yield during the first 180 days and B is the initial milk yield, namely, the milk yield during the first ten weeks of lactation.3. The interrelationships of persistency, initial milk yield and 180-day milk yield showed that these three characteristics are positively correlated with one another on a between cows within herd basis. This meant that it should be possible to combine high initial milk yield with high persistency to obtain increased total production.4. The effect of month of calving on persistency of lactation varied significantly between herds. On the average, the highest persistency was attained by cows calving in the winter, and the lowest by summer calvers.5. The variation of persistency with age showed that it is necessary to correct for the high persistency of first calvers when comparing cows with different lactations.6. The average repeatability of persistency was 0.242 in the present material, while heritability was of the order of 0.10–0.15.7. It has been concluded that improved feeding and management would bring about the greatest returns in the direction of improved persistency.

The effect of environment and heredity on lactation III. Butterfat percentage

1951 ◽  
Vol 41 (1-2) ◽  
pp. 94-97 ◽  
Author(s):  
P. Mahadevan
Keyword(s):  
Milk Yield ◽  
Statistical Study ◽  
Mass Selection ◽  
Present Material ◽  
South West ◽  
Selection For ◽  
Calving Intervals

1. On the basis of 5000 records from twelve leading herds of Ayrshire cattle in south-west Scotland for the period 1930–9, a statistical study has been made of some of the causes of variations which occur in butterfat percentage.2. Butterfat percentage was found to be affected only very slightly by month of calving, age and length of calving intervals.3. Selection for milk yield would not affect butterfat percentage adversely to any appreciable extent.4. The average repeatability of butterfat percentage was 0·691 in the present material, and heritability was of the order of 0·50–0·60.5. Mass selection would be an effective tool in bringing about improvement in butterfat percentage.

Factors affecting milk yield and lactation curve fitting in the creole sheep of Chiapas-Mexico

2005 ◽  
Vol 58 (3) ◽  
pp. 265-273 ◽  
Author(s):  
Marisela Peralta-Lailson ◽  
Arturo Ángel Trejo-González ◽  
Pastor Pedraza-Villagómez ◽  
José M. Berruecos-Villalobos ◽  
Carlos G. Vasquez
Keyword(s):  
Milk Yield ◽  
Curve Fitting ◽  
Factors Affecting ◽  
Lactation Curve ◽  
Fitting In

Factors affecting milk production in Improved Awassi dairy ewes

2000 ◽  
Vol 71 (3) ◽  
pp. 607-615 ◽  
Author(s):  
E. Gootwine ◽  
G. E. Pollott
Keyword(s):  
Milk Production ◽  
Litter Size ◽  
Milk Yield ◽  
Intensive Management ◽  
Short Term ◽  
Artificial Rearing ◽  
Factors Affecting ◽  
Lactation Curve ◽  
Total Milk ◽  
Term Variation

AbstractThis study investigated the factors affecting milk production and lactation curve parameters from the complete lactations of Awassi dairy sheep. The animals were kept in a single flock under intensive management and milked twice daily starting at lambing. Lambs were removed from the ewes at birth into an artificial rearing unit. The results of the analyses of 3740 complete lactations showed a mean litter size of 1·28 lambs born per ewe lambing and average total milk yield of 506 l from lactations 214 days in length and with an average lambing interval of 330 days. Mean lactation number was 3·71 and ewes conceived on average in the 6th month of the lactation. The lactations peaked on day 45 at a yield of 3·44 l. The maximum milk secretion potential of the ewes was 3·9 l/day, with milk yield increasing at 62 g/day mid way between lambing and peak yield and declining at 16·5 g/day mid way between peak and the end of lactation. Age at first lambing, lactation number, litter size, month of lambing and month of conception during the lactation had significant effects (P < 0·05) on some or all of the lactation parameters investigated. Relatively high milk yield was obtained in lactations starting in the January to March period. The monthly effect on milk production was explained by significant (P < 0·05) heat load and photoperiod effects. High milk production was found to have a significant (P < 0·05) adverse effect on reproductive performance. Conception followed a significant (P < 0·05) short term variation in milk production.

scholarly journals Factors affecting milk yield and ewe’s lactation curves estimated with test-day models

2011 ◽  
Vol 51 (No. 11) ◽  
pp. 483-490 ◽  
Author(s):  
M. Oravcová ◽  
M. Margetín ◽  
D. Peškovičová ◽  
J. Daňo ◽  
M. Milerski ◽  
...  
Keyword(s):  
Linear Model ◽  
Litter Size ◽  
Milk Yield ◽  
Fixed Effects ◽  
General Linear Model ◽  
Yield Variability ◽  
Factors Affecting ◽  
Lactation Curve ◽  
Daily Milk Yield ◽  
Daily Milk

Test-day records of purebred Tsigai, Improved Valachian and Lacaune ewes were analysed with a general linear model in order to investigate the effects of flock-test day, lactation number, days in milk, litter size and month of lambing. In total, 121 576 (Tsigai), 247 902 (Improved Valachian) and 2 196 (Lacaune) test-day records gathered over the period 1995&ndash;2005 were included in the analyses. Average daily milk yields were 0.604 &plusmn; 0.279 kg (Tsigai), 0.595 &plusmn; 0.243 kg (Improved Valachian) and 1.053 &plusmn; 0.475 kg (Lacaune). The significant (P &lt; 0.05) or highly significant (P &lt; 0.01) effects of flock-test day, lactation number (except for Lacaune), days in milk, litter size (except for Lacaune) and month of lambing (either fixed effects or covariates) tested by Fisher&rsquo;s tests were shown. The model explained about 50% of daily milk yield variability, with coefficients of determination as follows: 0.479 for Improved Valachian; 0.487 for Tsigai; 0.537 for Lacaune. Differences in estimated least-squares means were tested using multiple-range Scheffe&rsquo;s tests. A lower daily milk yield was found for the first lactation, single litter and lactations starting in March in comparison with daily milk yield for the second and third lactations (except for Lacaune), multiple litter and lactations starting in January and February (except for Improved Valachian). Ali-Schaeffer regression adopted for sheep was used for the fitting of lactation curve according to breed. &nbsp;

scholarly journals Conditioning Factors of Linearized Wood’s Function Lactation Curve Shape Parameters, Milk Yield, Fat and Protein Content in Murciano-Granadina Primiparous Does

Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2115
Author(s):  
Juan Vicente Delgado Bermejo ◽  
Francisco Antonio Limón Pérez ◽  
Francisco Javier Navas González ◽  
Jose Manuel León Jurado ◽  
Javier Fernández Álvarez ◽  
...  
Keyword(s):  
Milk Yield ◽  
Milk Fat ◽  
Random Regression ◽  
Total Production ◽  
Curve Shape ◽  
Conditioning Factors ◽  
Lactation Length ◽  
Lactation Curve ◽  
Daily Milk Yield ◽  
Daily Milk

A total of 137,927 controls of 22,932 Murciano-Granadina first lactation goats (measured between 1996–2016) were evaluated to determine the influence of the number of kids, season, year and farm on total milk yield, daily milk yield, lactation length, total production of fat and protein and percentages of fat and protein. All factors analyzed had a significant effect on the variables studied, except for the influence of the number of kids on the percentages of fat and protein, where the variation was very small. Goats with two offspring produced nearly 15% more milk, fat and protein per lactation compared to goats with simple kids. Kiddings occurring in summer–autumn resulted in average milk, fat and protein yields nearly 14, 19 and 23% higher when compared to winter–spring kiddings. Lactation curves were evaluated to determine the effects of the number of kids and season, using the linearized version of the model of Wood in random regression analyses. Peak Yield increased by about 0.3 kg per additional offspring at kidding, but persistence was higher in goats with single offspring. The kidding season significantly influenced the lactation curve shape. Hence summer-kidding goats were more productive, and peak occurred earlier, while a higher persistence was observed in goats kidding during autumn.

Factors affecting the lactation curves of intensively managed sheep based on a clustering approach

2013 ◽  
Vol 80 (4) ◽  
pp. 439-447 ◽  
Author(s):  
Laura Elvira ◽  
Fernando Hernandez ◽  
Pedro Cuesta ◽  
Santiago Cano ◽  
Juan-Vicente Gonzalez-Martin ◽  
...  
Keyword(s):  
Milk Yield ◽  
Clustering Analysis ◽  
Dairy Sheep ◽  
Dry Period ◽  
Factors Affecting ◽  
Lactation Curve ◽  
Total Milk ◽  
Clustering Approach ◽  
Intensively Managed ◽  
Selection Of

This study investigated factors affecting milk production and lactation curves from complete lactations of Lacaune dairy sheep. Animals were part of a single flock under intensive management and were milked twice daily starting at lambing. The results of the analyses of 7788 complete lactations showed an average total milk yield of 434±183 l from lactations 234±63 d long, with an average lambing interval of 302±65 d. A Pollott additive mathematical model was used to estimate complete lactation curves. Clustering analysis identified four lactation types among Lacaune dairy sheep differing mainly in productivity i.e. milk yield per lactation (MY) and length of lactation (DIM). The so-called SL type involved short, less productive lactations (n=2137; 27·4%; MY=222±75·5 l and DIM=182±52·9 d). The SN type involved short lactations of normal productivity (n=2039; 26·2%; MY=396±73·7 l and DIM=205±33·1 d). The LP type involved long and productive lactations (n=2169; 27·9%; MY=487±70·5 l and DIM=265±40·7 d), while the LVP type included long and extremely productive lactations (n=1443; 18·5%; MY=694±114·0 l and DIM=295±54·7 d). Sheep showing the best lactation curves were usually younger than other sheep, and they had higher yield during the previous lactation, a shorter previous dry period (55±50·4 for LP and 61±55·0 d for LVP types) and longer lambing intervals. In addition, they tended to be born in September and to lamb in March, October and December. Sheep were remarkably stable in their lactation curve behaviour: the curve type observed for the first lactation was highly likely to persist in subsequent lactations (P<0·0001). These results suggest that farmers can use the shape of the first lactation curve to guide their selection of ewes for breeding and retention on the farm, thereby improving flock productivity.

scholarly journals UDDER SIZE AND MILK PRODUCTION POTENTIALS OF GOATS AND SHEEP IN THE SOUTH WEST OF NIGERIA

2021 ◽  
Vol 24 (2) ◽  
pp. 175-179
Author(s):  
J. O. Agbede ◽  
A. G. Ologun ◽  
J. A. Alokan
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Coefficient Of Variation ◽  
Milk Protein ◽  
Goat Milk ◽  
West African ◽  
Production Potential ◽  
South West ◽  
Lactation Curve ◽  
Lactating Goats

Twelve adult lactating goats and sheep (2 to 2 ½ years old) comprising three groups of four each of West African Dwarf (WAD) goats and sheep and Yankasa ewes used for a nine week trial. The animals kidded and lambed between January and March. During these periods the udder sizes of the dams were measured weekly before hand milking thrice a week to derermine the milk yield. Samples of the milk were analysed for their composition. The results showed that the udder size increased with increasing milk yield (112 – 248ml) up to the peak of lactation which was between weeks 3 and 4 after parturition. Thereafter it decreased in size till the end of the experiment. The coefficient of variation (CV) of the udder size was influenced by breed. Udder size was positively correlated with milk yield. Milk yields were generally low or and ranged between 39 and 70ml and this was dependent on the behavior of the lactation curve. The milk protein and ash contents for the three breeds were comparable to those of the temperate breeds. Though Yankasa sheep exhibited the highest milk production potential, yet the peculiar characteristics of goat milk cannot be overlooked.

Modeling the lactation curve for test-day milk yield in Murciano-Granadina goats

2002 ◽  
Vol 46 (1) ◽  
pp. 29-41 ◽  
Author(s):  
C Fernández ◽  
A Sánchez ◽  
C Garcés
Keyword(s):  
Milk Yield ◽  
Lactation Curve

Factors affecting milk yield and prolificacy of Karagouniko sheep in West Thessaly (Greece)

1990 ◽  
Vol 24 (2) ◽  
pp. 181-186 ◽  
Author(s):  
I Hatziminaoglou ◽  
A Georgoudis ◽  
A Karalazos
Keyword(s):  
Milk Yield ◽  
Factors Affecting
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