The use of station and field tests for the improvement of milking performance in dairy cattle. II. Milking rate and time as indicators of a cow's milking ability

1968 ◽  
Vol 10 (2) ◽  
pp. 201-207 ◽  
Author(s):  
C. J. M. Hinks ◽  
E. O. Nielsen ◽  
A. Neimann-Sørensen

An investigation of milking ability in three dairy breeds has shown that selection for superior productive performance would contribute little to the improvement of milking time. The heritability of both average rate of flow and milking time was reasonably high in all three breeds, however, and direct selection should result in effective improvements.The problem of slow milking was more acute in the Danish Red breed, in which almost one cow in ten needed more than six minutes to milk out, than in the Black Pied or Danish Jersey breeds.A comparison of the average rate of flow and milking time as criteria of selection for milking ability indicated that both measures were equally effective in the Black Pied and Jersey breeds, but that rate of flow was considerably more (40%) effective than milking time in the Danish Reds. This was largely because the heritability of milking time in this breed was only one-third that of milking rate.It was concluded that the average rate of flow was to be preferred to milking time as a criterion of selection for milking ability in the Danish station testing programme.

1968 ◽  
Vol 10 (2) ◽  
pp. 209-212
Author(s):  
C. J. M. Hinks

The analysis was concerned with selective advantage as a possible cause of differences between breeds and individual animals in the relative proportions of milk obtained from the fore and rear quarters of the udder.Danish Jersey cattle were found to yield a significantly higher proportion of milk from the fore quarters than Danish Red and Danish Black Pied cattle (47% ν. 45% and 44% respectively).Very strong genetic relationships between the proportion of milk obtained from the fore quarters and lactation yields of milk and butterfat (rg = 0·92, 0·85) in the Jerseys, and correspondingly weak genetic relationships in the other two breeds, suggest that breed differences have arisen as a result of selection for productive performance operative upon different genetic relationships between production and the process controlling the partition of milk in the udder. It is suggested that differences between the breeds are likely to increase in the future.


1984 ◽  
Vol 64 (3) ◽  
pp. 505-512 ◽  
Author(s):  
B. W. KENNEDY

Feed efficiency in dairy cattle is moderately heritable and selection for its improvement theoretically would be effective. Despite this, direct selection for feed efficiency is not practiced in dairy cattle. Growth of milk recording programs which monitor feeding information has made selection for feed efficiency, or at least efficiency of concentrate conversion, possible on a large scale. However, it has been estimated that correlated response to direct selection for increased milk yield probably results in 70–95% of the potential improvement in feed efficiency that could be achieved through direct selection for feed efficiency. Current selection practices for increased body size may be detrimental to feed efficiency. In swine also, little direct selection for improved feed efficiency is practiced. Experimental studies for selection for feed efficiency have been less successful than expected. Correlated response from selection for an index that combines growth rate and backfat seems to be as effective in improving feed efficiency as direct selection. Development of automated feeding devices which allow measurement of individual feed intake under group penning will facilitate monitoring of and selection for improved feed efficiency. Key words: Selection, feed efficiency, swine, dairy cattle


Confectionery sunflower - a special area of use of sunflower, which requires the creation of marketable seeds quality features. One of the possible ways to create large-fruited sunflower is to create production hybrids and lines. Objective: to evaluate the created new large-fruited sunflower lines by a complex of morphological characters and determine the best lines for use as large-seeds hybrids as parent components or source material. In 2016-2019 years on the basis of the Institute of Oilseed Crops NAAS a study was conducted to assess the economic characteristics of large-fruited sunflower lines. We studied a collection of 27 lines of large-seeds sources. The lines were created by direct selection or crossing and sampling: Reyny of Argentinean origin, Zaporizhzhya confectionery variety, confectionery hybrid with striped pericarp color of Israeli origin, white seed of Turkish origin, synthetic population - donor of complex resistance. To study from the collection, lines were drawn that went through at least 7 generations with selection for seed size. Experience has shown that the shortest growing season for lines 174d and KP11 was 99 days, and the longest for lines I2K670 was 109 days. In the studied collection, the greatest mass of 1000 seeds has the KP11-146.47g line, which is the mother component and does not have branching. The second by weight of 1000 seeds (109 g) stood out line 168v, which also had branches and pollen fertility restoration genes and will be used as the paternal form. The third largest is also one basket line ZKN51-100. The collection included lines originating from the same combination, but with a different morphotype for the presence and absence of branching. So, based on the combination of KP11 x Zaporizhzhya Confectionery, three lines were obtained. A mass of 1000 seeds was observed in 98-86 g, with the branching line having the largest mass of 1000 seeds. The lines created with one combination VK678 x ZKN32: with a branch 168a had a mass of 1000 seeds 95g, and a line 168b - without a branch 109 g. Of the two lines obtained from the descendants of the combination KP11 x the striped hybrid both had branches, but the seeds were much smaller (weight of 1000 seeds 59 and 79 g). The collection also studied samples created on the basis of varieties and populations 160c, 174, 175b, the mass of 1000 seeds of which turned out to be more acceptable for large-fruited use from 83 to 99 g. Summing up the results of studying the collection of newly created lines, we can highlight the lines 162d, 168v, 175b, KP11 that are potentially promising for use in hybrids. The selections showed that large-fruited lines can be obtained from large-fruited varieties, self-pollination of large-fruited hybrids and crossing lines with hybrids and varieties. Self-pollination and selection of large-fruited lines in several generations does not provide the necessary variability for positive changes in selections. The result of the selection by weight of 1000 seeds in the offspring from crosses and from populations creates opportunities for new large-seeds sunflower.


1984 ◽  
Vol 4 (12) ◽  
pp. 2929-2931 ◽  
Author(s):  
K Blochlinger ◽  
H Diggelmann

The DNA coding sequence for the hygromycin B phosphotransferase gene was placed under the control of the regulatory sequences of a cloned long terminal repeat of Moloney sarcoma virus. This construction allowed direct selection for hygromycin B resistance after transfection of eucaryotic cell lines not naturally resistant to this antibiotic, thus providing another dominant marker for DNA transfer in eucaryotic cells.


2005 ◽  
Vol 62 (4) ◽  
pp. 357-365 ◽  
Author(s):  
Giovani Benin ◽  
Fernando Irajá Félix de Carvalho ◽  
Antônio Costa de Oliveira ◽  
Claudir Lorencetti ◽  
Igor Pires Valério ◽  
...  

Several studies have searched for higher efficiency on plant selection in generations bearing high frequency of heterozygotes. This work aims to compare the response of direct selection for grain yield, indirect selection through average grain weight and combined selection for higher yield potential and average grain weight of oat plants (Avena sativa L.), using the honeycomb breeding method. These strategies were applied in the growing seasons of 2001 and 2002 in F3 and F4 populations, respectively, in the crosses UPF 18 CTC 5, OR 2 <FONT FACE=Symbol>´</FONT> UPF 7 and OR 2 <FONT FACE=Symbol>´</FONT> UPF 18. The ten best genetic combinations obtained for each cross and selection strategy were evaluated in greenhouse yield trials. Selection of plants with higher yield and average grain weight might be performed on early generations with high levels of heterozygosis. The direct selection for grain yield and indirect selection for average grain weight enabled to increase the average of characters under selection. However, genotypes obtained through direct selection presented lower average grain weight and those obtained through the indirect selection presented lower yield potential. Selection strategies must be run simultaneously to combine in only one genotype high yield potential and large grain weight, enabling maximum genetic gain for both characters.


1983 ◽  
Vol 36 (2) ◽  
pp. 159-164
Author(s):  
D. Croston ◽  
J. L. Read ◽  
D. W. Jones ◽  
D. E. Steane ◽  
C. Smith

ABSTRACTThirteen pairs of Suffolk rams were selected on high and low 18-month adjusted live weight from six farms over 2 years, to establish the relationship between 18-month weight and early lamb growth. Progeny were first produced in recorded crossbred flocks (618 lambs) and then in an experimental flock of crossbred ewes (1083 lambs). Different results were obtained from the recorded and experimental flocks. The regressions of lamb 12- to 13-week weight on ram 18-month weight (within farm deviation) were 0·053 ± 0·022 kg and –0·004 ± 0·020 kg, respectively. These regressions for indirect selection correspond to ‘effective’ heritabilities for direct selection for lamb growth of 0·18 ± 0·07 and 0·02 ± 0·06 respectively. Improvement of early Iamb growth is discussed and it is concluded that selection for 18-month weight is unlikely to be a useful method.


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