The extent of selection for milk yield among cows of the Jamaica Hope breed

1970 ◽  
Vol 74 (3) ◽  
pp. 469-471 ◽  
Author(s):  
K. L. Roache ◽  
K. E. Wellington ◽  
P. Mahadevan
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Total Population ◽  
Dairy Herds ◽  
Response To Selection ◽  
Apparent Lack ◽  
Selection For ◽  
The Government ◽  
Using Data ◽  
The Tropics

SUMMARYUsing data (1950–64) from the government-owned herd of Jamaica Hope cattle at Bodles, Jamaica, it was estimated that the fraction of cows called on the basis of their milk production in any given lactation was of the order 0·00 to 0·05. Using data (1967–68) from ten high–and ten low-producing farmer herds of the same breed, it was found that the level of calling was low and that cows proceeding from one lactation to the next had a yield superiority over the total population of only + 4 gallons. It is suggested that one of the principal reasons for the apparent lack of response to selection in dairy herds in the tropics may be that little or no selection for production is in fact practised.

scholarly journals Trends in milk production, calving rate and survival of cows in 14 Irish dairy herds as a result of the introgression of Holstein-Friesian genes

2006 ◽  
Vol 82 (4) ◽  
pp. 423-433 ◽  
Author(s):  
R. D. Evans ◽  
P. Dillon ◽  
F. Buckley ◽  
D. P. Berry ◽  
M. Wallace ◽  
...  
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Positive Impact ◽  
Direct Selection ◽  
Dairy Herds ◽  
Holstein Friesian ◽  
Parity Number ◽  
Impact On Survival ◽  
Negative Effect ◽  
Calving Rate

AbstractTrends in milk production, calving rates, and survival were monitored on a potential 5580 primiparous and multiparous Holstein-Friesian dairy cows across 14 Irish seasonal spring-calving dairy farms between the years 1990 and 2001. Over this period calving rate to first service (CALV1) reduced by 0·96% per year (55 to 44%;P< 0·001), calving rate to first and second service (CALV12) reduced by 0·84% per year ( 77 to 70%;P< 0·001) and herd average parity number reduced by 0·10 lactation per year (4·3 to 3·5;P<0·001). The proportion of North American Holstein Friesian (NAHF) genes in the cows increased by 5·5% per year (8 to 63%;P<0·001), while pedigree index for milk yield (PIMILK) of the cows increased by 25 kg per year (P<0·001). The predicted difference of the sires of the cows for calving interval and survival increased by 0·5 days (P<0·001) and reduced by 0·12% (P<0·001) per year, respectively. A negative association was found between increased phenotypic milk yield, NAHF and PIMILKand reduced calving rates as assessed by CALV1 and CALV12. Increased proportion of NAHF genes exhibited a negative effect on survival (P<0·001) whereas increased levels of heterosis had a positive impact on survival (P<0·001). The results of the present study indicate that in seasonal calving herds in Ireland a need for direct selection on traits related to fertility and survival is required to arrest and reverse the declining trends in calving rates and survival.

Evaluation of Cornell Net Carbohydrate and Protein System predictions of milk production, intake and liveweight change of grazing dairy cows fed contrast silages

2006 ◽  
Vol 144 (1) ◽  
pp. 85-91 ◽  
Author(s):  
A. V. CHAVES ◽  
I. M. BROOKES ◽  
G. C. WAGHORN ◽  
S. L. WOODWARD ◽  
J. L. BURKE
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Systematic Bias ◽  
Protein System ◽  
Nutrient Partitioning ◽  
Sources Of Variation ◽  
Physical Limitations ◽  
Predicted Values ◽  
Using Data ◽  
Grazing Dairy Cows

The importance of mechanistic models for ration balancing with forages is indicated and physical limitations to intake emphasized, because these limit energy and nutrient supply to cows grazing forages, especially grass. Ration-balancing models using fresh or ensiled forages to complement pasture will need to accommodate intake limitations due to rumen fill, clearance, chewing or other criteria. The potential of the Cornell Net Carbohydrate and Protein System (CNCPS) model to predict milk production from diets based on pasture and forage supplements was tested using data from two experiments. Data were obtained from studies in which pasture was complemented with contrasting silages including maize, pasture, sulla, lotus and forage mixtures, comprising 0·30–0·40 of dry matter intake (DMI). Twelve diets were used in the evaluation. DMI, liveweight (LW), days in milk, and diet composition were determined during the trials and used as inputs in the model. Across all diets, a significant relationship existed between predicted and actual values for DMI (R2=0·58), milk yield (R2=0·59) and LW change (R2=0·51), but there were still large unexplained sources of variation. No significant mean bias was observed for any of the variables, but the slope of residual differences against predicted values was significantly different from zero for milk yield, LW change and for DMI (P<0·06). The results indicate a satisfactory prediction of milk production when cows are neither gaining nor losing weight, but that a systematic bias exists probably because of the failure of the CNCPS model to account for energy and nutrient partitioning.

Selection practices in dairy herds. 1. First lactation performance and survival to the second lactation

1966 ◽  
Vol 8 (3) ◽  
pp. 467-480 ◽  
Author(s):  
C. J. M. Hinks
Keyword(s):  
Milk Yield ◽  
Selection Procedure ◽  
Dairy Herds ◽  
Productive Capacity ◽  
Lactation Performance ◽  
Selection For ◽  
Calving Season ◽  
Main Determinants ◽  
The Relationship ◽  
Selection Of

1. The relationship between first lactation performance and the ability of individual animals to survive to the second lactation has been examined in Friesian and Ayrshire populations in an attempt to isolate the main determinants of survival, and to rationalise an apparently complicated selection procedure.2. Low milk yield was the most important single cause of culling in the first lactation, though the two breeds differed considerably in the relative importance of milk yield in the selection programme. Natural wastage, caused by factors beyond the control of the farmer, accounted for the disposal of 5·7% of the population during the first lactation. Selection for butterfat was marginal in both populations, and could only be detected at extreme butterfat percentages, where high butterfat tended to compensate for a poor milk yield, and low butterfat to confirm a decision to cull an average yielding animal. Survival was not significantly affected either by the size of the herd or by the age at calving.3. The proportion culled, and the intensity and effectiveness of selection for milk yield, were inversely related to the level of herd performance, and were greater in summer calving animals than in winter calvers.4. The analysis indicated that selection for milk yield in different environments could be adequately described in terms of the Normal Curve. Yield-survival curves were computed and compared for groups of animals in different herd and calving season environments. When milk yield was expressed in terms of the deviation from the herd-year average, it was found that summer calvers, and animals in low yielding herds, had to demonstrate a productive capacity of far greater individual merit, if their chances of survival were to match those of their winter calving herdmates, and those of their contemporaries in higher yielding herds. When milk yield was expressed in absolute terms the survival of individual animals of similar yield was comparable in all herd and season environments. It was concluded that all the herds included in the analysis had been subject to the same absolute standards of milk yield in the selection of first calvers.

An analysis of the Entebbe herd of Nganda cattle in Uganda

1961 ◽  
Vol 3 (1) ◽  
pp. 29-39 ◽  
Author(s):  
P. Mahadevan ◽  
H. J. S. Marples
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Production Performance ◽  
Calving Interval ◽  
Indigenous Cattle ◽  
Factors Affecting ◽  
Lactation Length ◽  
The Government ◽  
To Come ◽  
Daily Milk Yield

In the herd of Nganda cattle at the Government Livestock Experiment Station, Entebbe, Uganda, it was found that of the known environmental factors affecting milk production, the more important ones were age (in lactations) and length of the calving interval preceding the second and third lactations. The correlations between performance in different lactations of the same animal were high for lactation milk yield (0·73) and average daily milk yield (0·62) and low for calving interval (0·21) and dry period (0·15). The repeatability of lactation length was intermediate (0·42). The heritability values were around 0·3 for the weight measurements, around 0·2 for yield characteristics and around 0·1 for length of lactation and age at first calving.The sires used in the breeding programme at Entebbe made little impact on production performance in the herd. The estimated genetic improvement in milk yield through selection of dams of cows was also low. It is argued from comparison with results from other parts of the tropics that superior genotypes for milk production are difficult to come by among indigenous cattle in these areas and that we should therefore look for other opportunities and methods to move ahead faster in the future.

MILK YIELD IN LINES OF MICE SELECTED FOR GROWTH OR MATERNAL ABILITY

1975 ◽  
Vol 17 (2) ◽  
pp. 263-268 ◽  
Author(s):  
J. M. White
Keyword(s):  
Milk Yield ◽  
Body Weight Gain ◽  
Correlated Response ◽  
Response To Selection ◽  
Litter Weight ◽  
Average Production ◽  
Before And After ◽  
Selection For ◽  
And Control ◽  
Gain Line

Two experiments were conducted to measure milk yield as a correlated response to selection for increased 12-day litter weight (maternal lines) for 13 generations and increased and decreased body weight gain from 21 to 42 days of age (postweaning gain lines) for 12 to 14 generations. Milk yield was measured from day 6 to day 21 of lactation by separating litters from their dams for 6 h, then weighing litters before and after a 1.5 h suckling period. Average total milk production was 30.3 ± 0.9 g and 28.6 ± 1.1 g in maternal and control lines, respectively. This difference was not significant (P > 0.05). Differences among gain lines were significant (P < 0.01) in the second experiment with average production of 44.1 ± 1.4 g for increased gain lines, 22.5 ± 0.9 g for the decreased gain line and 31.2 ± 1.0 g for the control. These results indicated that response to selection for increased 12-day litter weight was not associated with increases in milk yield, but sizable changes in milk yield accompanied bi-directional selection for early postweaning gain.

Skin structure and milk production of British dairy cattle

1964 ◽  
Vol 31 (1) ◽  
pp. 53-58 ◽  
Author(s):  
T. Nay ◽  
D. McEwan Jenkinson
Keyword(s):  
Dairy Cattle ◽  
Hair Follicle ◽  
Milk Production ◽  
Milk Yield ◽  
Dairy Herds ◽  
Progeny Testing ◽  
Extensive Investigation ◽  
Skin Structure

SummaryThe possibility of using a skin measurement as an index of potential milkproducing capacity in cattle was re-examined. Skin specimens were obtained by biopsy from 7 dairy herds, and each of 5 anatomical measurements was correlated with (1) milk yield and (2) butterfat percentage.Only one of the pooled within-herd relationships was statistically significant. This relationship indicated that within the breeds studied, cows with the least hair follicle depth would be expected to give the highest milk yield. It is suggested that a more extensive investigation of this relationship might yield results of practical value in assessing milk-producing capacity and in progeny testing.

scholarly journals Impact of frequency of milking on milk yield and fertility of Holstein cows undergoing extended lactations due to failure to conceive

2021 ◽  
pp. 113
Author(s):  
Jesús Mellado ◽  
Jessica Flores ◽  
Francisco G. Véliz ◽  
Ángeles de Santiago ◽  
José E. García ◽  
...  
Keyword(s):  
Observational Study ◽  
Milk Production ◽  
Milk Yield ◽  
Reproductive Performance ◽  
The Other ◽  
Holstein Cows ◽  
Dairy Herds ◽  
Northern Mexico ◽  
Total Milk ◽  
Services Per Pregnancy

The objective of this observational study was to determine the effect of two (2x) compared to three (3x) times a day milking in Holstein cows undergoing lactations ≥600 d on milk production and reproductive performance. Two large adjacent commercial dairy herds with similar size, facilities, and management in a hot area of northern Mexico (25° N) were used. Cows in one herd (n= 214) were milked two times a day (2x), the other herd was milked three times a day (3x; n=245) and both groups were milked for at least 600 days. For cows in first lactation, total milk yield did not differ between 3x and 2x cows (19796 ± 3354 vs. 19269 ± 3652 kg; p > 0.10) in lactations with an average of 696 and 650 days in milk (DIM), respectively. Multiparous 3x cows produced more total milk days than 2x cows (20942 ± 3920 vs. 18910 ± 2632 kg; p < 0.01) with greater (p < 0.01) DIM for 3x (685 ± 117 days) than 2x (631 ± 88 days) cows. Lactation persistence was greater (p < 0.05) in 2x (62 ± 9%) than 3x (60 ± 10%) cows. Overall conception rate (CR) did not differ between 2x and 3x cows (53.3% vs. 49.8%) but 3x cows required one more service (p < 0.01) to get pregnant than 2x animals.  Given that average milk yield throughout the complete lactation did not differ between 2x (29.8 ± 2.0 kg) and 3x (29.3 ± 2.9 kg) cows, it was concluded that two-times-a-day milking is equally effective as three-times-a-day milking to attain acceptable milk yield in lactations over 600 days. However, reproductive performance based on first-service CR and services per pregnancy was negatively affected by three-times-a-day milking.

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