Heritability of milk yield and composition at different levels and variability of production

1983 ◽  
Vol 36 (1) ◽  
pp. 59-68 ◽  
Author(s):  
W. G. Hill ◽  
M. R. Edwards ◽  
M.-K. A. Ahmed ◽  
R. Thompson
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Coefficient Of Variation ◽  
Milk Fat ◽  
Protein Production ◽  
Genetic Correlations ◽  
Progeny Testing ◽  
Low Levels ◽  
High Level ◽  
Different Levels

ABSTRACTAnalyses of variance were conducted on first lactation milk, fat and protein production records in England and Wales of daughters of British Friesian sires. Herds were split on milk yield into high and low levels of mean production and, in subsequent analyses, into high and low levels of within herd variance and coefficient of variation using all first lactation records. Data were then extracted on daughters of 798 young sires undergoing progeny test and on 118 widely used proven sires to generate connections. Least squares analyses were conducted within levels and genetic correlations estimated from the covariance of sire effects. W ith data split on mean yield, the heritability of milk yield was 0·24 at the low level and 0·30 at the high level, that of log transformed yield being 0·25 and 0·35 respectively.With data split on variance the corresponding figures were 0·24, 0·30, 0·27 and 0·36 respectively, and when split on coefficient of variation, 0·22,0·26,0·26 and 0·32. There were similar increases for fat and protein yield, proportionately smaller increases for fat and protein content.Genetic correlations were close to 1·0 between high and low levels for all traits on all criteria of data splitting. As a consequence progeny testing of bulls is rather more accurate at high mean or variance of production levels and data can be combined optimally without scaling. Cows of the highest predicted value using an index will be found in high variance herds.

scholarly journals The chemical composition and technological properties of milk obtained from the morning and evening milking

2008 ◽  
Vol 56 (5) ◽  
pp. 187-198 ◽  
Author(s):  
Martin Skýpala ◽  
Gustav Chládek
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Milk Fat ◽  
Protein Production ◽  
Milk Protein ◽  
Fat Content ◽  
Total Solids ◽  
Milk Protein Content ◽  
Solids Content ◽  
Morning Milk

Milk yield varies during lactation, following what is termed a lactation curve. ŽIŽLAVSKÝ and MIKŠÍK (1988) recorded changes in milk yield within a day, too. TEPLÝ et al. (1979) a KOUŘIMSKÁ et al. (2007) published variation within a day ± 1.10 kg in milk yield, ± 0.75 % in milk fat content and ± 0.20 % in milk protein content. Milk yield of cows can be expressed in many different ways, for instance, in kilograms per lactation or in kilograms per day. A practical parameter describing milk production is milk yield (kg) per milking.The object of experiment were 12 cows of Holstein cattle on the first lactation from the 100-day of lactation to 200-day of lactation. The samples of milk were collected from January to May 2007, once a month from the morning and evening milking (milking interval 12 h ± 15 min.). The following parameters were monitored: milk production – milk yield (kg), milk protein production (kg), milk fat production (kg); milk composition – milk protein content (%), milk fat content (%), lactose content (%), milk solids-not-fat content (%), milk total solids content (%); technological properties of milk – ti­tra­tab­le acidity (SH), active acidity (pH), rennet coagulation time (s), quality of curd (class) and somatic cell count as a parameter of udder health.Highly significant differences were found (P < 0.01) between morning milk yield (15.7 kg) and evening milk yield (13.8 kg), between morning milk protein production (0.51 kg) and evening milk protein production (0.45 kg) and between evening milk fat content (4.41 %) and morning milk fat content (3.95 %). A significant difference (P < 0.05) was found between morning milk total solids content (12.62 %) and evening milk total solids content (12.07 %). No significant differences were found between morning (M) and evening (E) values of the remaining parameters: milk fat production (M 0.62 kg; E 0.60 kg), milk protein content (M 3.24 %; E 3.27 %), milk lactose content (M 4.78 %; E 4.86 %), milk solids-not-fat content (M 7.69 %; E 7.71 %), somatic cell count (M 80 000/1 mL; E 101 000/1 mL), titratable aci­di­ty (M 7.75 SH; E 7.64 SH), active acidity (M pH 6.58; E pH 6.61), rennet coagulation time (M 189 s.; E 191 s.), quality of curd (M 1.60 class; E 1.57 class).

scholarly journals Schätzung genetischer Parameter für Testtagsergebnisse von Milchleistungsmerkmalen bei Bunten Deutschen Edelziegen

2004 ◽  
Vol 47 (2) ◽  
pp. 193-202
Author(s):  
D. Bömkes ◽  
H. Hamann ◽  
O. Distl
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Milk Fat ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Protein Yield ◽  
Lower Saxony ◽  
Genetic Progress ◽  
Performance Traits ◽  
Milk Performance

Abstract. Title of the paper: Estimation of genetic parameters for test day records of milk performance traits in German Improved Fawn The objectives of this study were to estimate genetic parameters for milk performance traits of German Improved Fawn by using univariate und multivariate animal models. The analysis was based on 27,778 test day records of 1,848 German Improved Fawn with 3,574 lactation records distributed over 229 flocks in Lower Saxony, Saxony and Baden-Wuerttemberg. Milk records were sampled between 1988 and 2002. The animals in our analysis were the progeny of 455 sires and 1.148 does. Heritabilities estimated with a multivariate test day model with fixed regression were h2 = 0.19, 0.16 and 0.15 for milk, fat and protein yield. For fat and protein content and Somatic Cell Score (SCS) heritabilities were h2 = 0.17, 0.14 and 0.16, respectively. The additive genetic correlations between milk yield and fat as well as protein yield of German Improved Fawn were very high and positive (rg = 0.84 and rg = 0.77). Milk yield and milk contents were genetically negative correlated with rg = −0.28 for fat and rg = −0.22 for protein content. A moderate additive genetic correlation (rg = 0.48) between fat and protein content was estimated. There were no considerable additive genetic correlations between fat yield and protein content as well as between fat content and protein yield (rg = 0.05 and rg = 0.09). Additive genetic correlations between milk, fat or protein yield and SCS were high and negative, whereas additive genetic correlations between fat or protein content and SCS were low and positive. The genetic parameters estimated from field test records allow to achieve genetic progress in milk performance traits of German Improved Fawn.

scholarly journals Evaluation of highly productive cows by selection and genetic parameters

2020 ◽  
Vol 22 (93) ◽  
pp. 22-28
Author(s):  
T. V. Pidpala ◽  
Yu. S. Matashnyuk
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Negative Correlation ◽  
Milk Fat ◽  
Genetic Parameters ◽  
Fat Content ◽  
Holstein Cows ◽  
Milk Productivity ◽  
Medium Level ◽  
High Level

Under the conditions of intensive technologies used in production of livestock products, the main selection feature that characterizes the economic feasibility of dairy farming and breeding value of animals is milk productivity. One of the factors that affects, not only the economy of production, but also the improvement of herds and breeds of cattle, is the use of highly productive cows. Therefore, the aim of our research was to assess the level of development of productive traits in Holstein cows under the conditions of intensive milk production technology, according to selection and genetic parameters. To conduct the study, a group of 1089 first-born cows was formed with the help of the Dairy Comp program and Microsoft Excel. The material for the research was the milk productivity of Holstein cows during the first three lactations. The level of development of selection traits in animals was determined by selection and genetic parameters. It was found that from the sample n = 1089 to the group of highly productive animals (“>10560”) were included 266 cows, and low-productive animals (“<8706”) – 249 first-borns. They had an average milk yield for the first lactation, 11439 kg of milk with a fat content of 3.96 % and 7737 kg of milk and 3.95 %, respectively. There is a difference in milk yield, milk fat and protein between the groups of cows “>10614” and “<8706”, but there is a general tendency towards changes in productivity with age. Based on the data of milk recurrence and the amount of milk fat of high-yielding cows (group “>10614”), it was found that higher values of the coefficient are characteristic of lactations I–III (rw= 0.105; rw= 0.135). As a result of comparative analysis it was found that low-yielding animals (group “<8706”) were characterized by higher recurrence rates for I–II and I–III lactation (rw = 0.345;rw = 0.316;rw = 0.320 and rw = 0.664;rw = 0.646;rw = 0.651, respectively). Higher rates of recurrence of traits of milk productivity are the characteristic of low-yielding cows (group “<8706”), i.e. they had more consistency of traits during different lactations and animals with a high level of productivity did not differ in age constancy. At a high level of milk yield in cows of group “>10614” appeared a negative correlation of low and medium level (r = -0.423). It was also found a negative correlation of low and medium level between milk yield and protein content in milk (r = -0.007… -0.332). At lower milk yields, there is no negative correlation between milk yield and fat content in milk. Thus, the existence of a negative correlation between milk yield and fat content in milk at a high level of animal productivity, and between milk yield and protein content in milk at both high and low levels of cow productivity was proved.

Progeny testing dairy bulls at different management levels

1960 ◽  
Vol 2 (2) ◽  
pp. 141-152 ◽  
Author(s):  
Alan Robertson ◽  
L. K. O'Connor ◽  
J. Edwards
Keyword(s):  
Milk Yield ◽  
Coefficient Of Variation ◽  
Progeny Testing ◽  
Gradual Change ◽  
Breeding Values ◽  
England And Wales ◽  
True Breeding ◽  
The Mean ◽  
Dairy Bulls ◽  
Different Levels

1. Records used to compile the Contemporary Comparisons of 57 Friesian, 8 English Ayrshire and 11 Scottish Ayrshire A.I. bulls, each with at least 100 ‘effective daughters’ were analysed.2. For each bull, the herd-years were divided into three equal groups on the basis of the average heifer yield of both daughters and contemporaries (high-, medium-, and low-producing herd-years) and three independent Contemporary Comparisons were calculated for each bull, one at each of the three yield levels.3. In the data from England and Wales, the mean Contemporary Comparison declined with increasing mean level of production. This decline was such as to imply that some 20% of the differences in production between herds were genetic in origin. A possible explanation lies in the gradual change from Dairy Shorthorn to Friesian and Ayrshire which has taken place in England and Wales, but not in Scotland, during the last 15 years.4. The variance within progeny groups within herd-years increased from the low level to the high but the coefficient of variation decreased slightly. The variance between sires also increased with the mean level of production but almost exactly in parallel with that within sires so that the heritability and consequently the accuracy of the progeny test for milk yield was effectively the same at all production levels.5. The correlation between the true breeding values of the bulls at the different levels was very close to one.6. From these results it is concluded that there is no need to provide special strains within breeds to suit particular management levels or to concentrate progeny testing in the higher-producing herds and that daughter records from all herds, irrespective of level of production, can be used with equal confidence.

Relationship between milk composition and yield of milk, fat and protein in Red Danish cattle

1968 ◽  
Vol 10 (4) ◽  
pp. 445-450 ◽  
Author(s):  
K. Christensen
Keyword(s):  
Milk Yield ◽  
Milk Fat ◽  
Genetic Correlations ◽  
Protein Yield ◽  
Direct Selection ◽  
Correlated Response ◽  
Logarithmic Scale ◽  
Progeny Testing ◽  
Fat Yield ◽  
Selection For

The relationships among five traits in dairy cattle (milk yield, fat yield, protein, fat % and protein %) were examined on the original and on a logarithmic scale. The data comprised the records on 5333 Red Danish cows tested at the Danish Progeny Testing Stations during the years 1960–66. None of the heritabilities or the correlations among the variates were altered appreciably by transformation. For the five traits heritability estimates were 0·56, 0·80, 0·65, 0·64 and 0·56, respectively. Phenotypic and genetic correlations among milk yield, fat yield and protein yield were all very high, about 0·95. The correlations between fat % and protein % were about 0·6. The coefficient of variation of a variate proved to be a good approximation of the standard deviation of the transformed variate even for milk, fat and protein yield with coefficients of variation of 17–18%. It was concluded that little is likely to be gained by using index selection for fat yield and protein yield. However, about 90% of the response obtainable by direct selection for fat or protein yield could be obtained merely by selection for milk yield. A large correlated response for protein yield could be obtained by selecting for fat yield.

The effects of nutritional level on milk yield and milk composition in cows and heifers

1971 ◽  
Vol 38 (3) ◽  
pp. 287-294 ◽  
Author(s):  
S. Gordin ◽  
R. Volcani ◽  
Yehudith Birk
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Protein Production ◽  
Milk Composition ◽  
Fat Content ◽  
Fat Percentage ◽  
Fat Yield ◽  
Nutritional Level ◽  
Total Fat ◽  
High Level

SummaryThe effects of diets high in concentrates and low in roughage on the yield of milk and milk constituents were studied in 32 cows and heifers throughout lactation. A high level of concentrates in the ration caused an increase in milk yield, a decrease in fat percentage but not in total fat yield, and an increase in protein production.Milk produced under such feeding conditions is capable of yielding greater quantities of curd than would be expected from its fat content, and should be evaluated accordingly. Feed requirements of the cows should be assessed not solely on the basis of the fat content of their milk but also in accordance with the protein content.

Milk productivity of the cows of Holstein and Simmental breeds in environment of the Novosibirsk region

2020 ◽  
pp. 41-49 ◽  
Author(s):  
A. Zheltikov ◽  
N. Kostomakhin ◽  
D. Adushinov ◽  
O. Zaiko ◽  
V. Dementev ◽  
...  
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Milk Fat ◽  
Correlation Coefficients ◽  
Live Weight ◽  
Fat Content ◽  
Milk Productivity ◽  
Holstein Breed ◽  
Novosibirsk Region ◽  
Daily Milk Yield

The characteristic of milk productivity of cows of Holstein and Simmental breeds in LLC “Sibirskaya Niva” in the Maslyaninsky district in the Novosibirsk region has been given. It has been revealed that under the natural and climatic environments of the Western Siberia, when creating favorable conditions for feeding and housing for cows of Holstein and Simmental breeds have sufficiently high milk productivity. It has been found that Holstein first-calf heifers surpassed their Simmental herdmates by 959 kg in milk yield for the first 305 days of lactation under the same conditions of housing and feeding, by 3,1 kg in daily milk yield, by 38,2 kg in milk fat yield, and by 28,3 kg in milk protein yield (P < 0,001). There were no statistically significant differences between animals of Holstein and Simmental breeds in terms of fat and protein content in milk, which amounted to 3,94 and 2,96 % in Holstein breed and 3,97 and 2,98 % in Simmental breed, respectively. Both breeds have shown high milk productivity during the first 3 lactations. Thus, the milk yield of Holstein cows for the first 3 lactation was 6475–9290 kg, Simmental cows it was 5516–7680 kg, fat content was 3,93–3,99 and 3,96–3,97 %, respectively. The protein content in the milk of cows of both breeds did not exceed 3,0 %. High variability has been found in milk yield, yield of milk fat and protein, the coefficient of milk content and duration of lactation, the lowest in the content of protein and fat in milk and live weight. The correlation coefficients between the fat and protein content in milk were generally positive, but did not exceed 0,28. Therefore, breeding in the herd of cows in LLC “Sibirskaya Niva” have to be conducted not only by fat content, but also by protein content in milk.

Effect of intravenous supplements of L-methionine on milk yield and composition in cows given silage-cereal diets

1982 ◽  
Vol 49 (1) ◽  
pp. 25-28 ◽  
Author(s):  
David G. Chamberlain ◽  
Phillip C. Thomas
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Perennial Ryegrass ◽  
Milk Fat ◽  
Fat Content

SUMMARYEight cows in mid lactation and receiving a diet of perennial ryegrass silage and barley (70:30 on a DM basis) were given intravenous supplements of l-methionine (8 g/d). The methionine treatment had no significant effect on milk yield, protein content or lactose content, but increased milk fat content and yield by approximately 10% (P < 0·05).

The progeny testing of dairy bulls at different levels of production

1956 ◽  
Vol 47 (4) ◽  
pp. 367-375 ◽  
Author(s):  
I. L. Mason ◽  
Alan Robertson
Keyword(s):  
Artificial Insemination ◽  
Coefficient Of Variation ◽  
Genetic Variance ◽  
Comparison Method ◽  
Breeding Value ◽  
Progeny Testing ◽  
Average Yield ◽  
Average Production ◽  
Dairy Bulls ◽  
Different Levels

1. An analysis has been made of milk records from 13,000 cows bred by artificial insemination in Denmark.2. The herds were divided into three equal groups on the basis of their average production. The variance of yield within herds increased as the average yield increased, but the coefficient of variation declined slightly. The genetic variance was more than five times as large in the high-yielding herds than in the low, and correspondingly the heritabilities in low, medium and high herds were 0·05, 0·15 and 0·22 respectively. These were estimated from the variation observed between progeny groups of the same 152 bulls at each production level.3. No evidence was obtained of any sire-herd interaction for yield, either within or between management levels. The true ranking of bulls for breeding value was apparently the same at all levels.4. The heritability of fat content in the three groups was 0·27, 0·47 and 0·49 respectively, and no evidence of sire-herd interaction was found.5. The contemporary comparison method of assessing A.I. bulls for yield was found to have the accuracy expected in theory.6. These results are discussed in relation to those of other workers with which there are some discrepancies. On our results, a policy of choosing bulls on the basis of their daughters' performance in high-yielding herds should be the most satisfactory way of progeny-testing bulls used in artificial insemination.

scholarly journals Structural and non-structural carbohydrates in concentrate supplements of silage-based dairy cow rations. 1. Feed intake and milk production.

1990 ◽  
Vol 38 (3B) ◽  
pp. 487-498
Author(s):  
H. de Visser ◽  
P.L. van der Togt ◽  
S. Tamminga
Keyword(s):  
Protein Content ◽  
Milk Yield ◽  
Feed Intake ◽  
Milk Fat ◽  
Milk Protein ◽  
Basal Diet ◽  
Negative Energy ◽  
Net Energy ◽  
Rumen Degradation ◽  
Silage Maize

A feeding trial was carried out with 64 multiparous dairy cows, in which the effect of type of carbohydrate in concentrate mixtures (starch vs. cell wall constituents) and differences in rumen degradation (fast vs. slow) on feed intake and milk yield were studied. The experiment started immediately after parturition and lasted for 15 wk. The basal diet, which comprised 75% of the total DM intake, consisted of wilted grass silage, maize silage and concentrates. The remaining part of the diet consisted of barley (B), maize (M), pressed ensiled beet pulp (P) or moist ensiled maize bran (MB). All diets were given as totally mixed rations. Total intake of DM and net energy did not differ between diets, but differences were found in energy partition. There was a tendency for cows given diet B to show increased liveweight gain, while cows given P mobilized more body reserves compared with the other treatments. Milk yield did not differ between diets, but milk fat content was higher for diet P. Milk protein content was higher for diets B and M compared with P and MB. The lower protein content of the milk of treatment P can be explained by a longer period of negative energy balance, while the lower milk protein in cows given diet MB probably resulted from reduced microbial protein synthesis. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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