The present study was carried out using first lactation monthly test-day milk yield records of 466 crossbred (HF × Sahiwal) cattle calved from 2000 to 2018 sired by 89 bulls maintained at Directorate of Livestock Farms, GADVASU, Ludhiana. Mixed model analysis was carried out by least-squares maximum likelihood programme to study the effects of non-genetic factors on first full lactation milk yield (FFLMY), first lactation 305-day milk yield (FL305MY) and monthly test-day (TD) milk yield records of crossbred cattle. The least squares means of different monthly TD milk yields (1st to 11th) were 12.05 ± 0.42, 15.65 ± 0.42, 15.38 ± 0.44, 14.44 ± 0.43, 13.79 ± 0.41, 12.88 ± 0.40, 12.27 ± 0.42, 11.83 ± 0.37, 10.85 ± 0.42, 10.64 ± 0.45 and 10.28 ± 0.50 kg, respectively. For FFLMY and FL305MY the means were 4979.60±184.45 and 3818.17±103.26 kg. The effects of different AFC groups were non-significant on TDs and FL305MYs, whereas it was significant (p<0.01) for FFLMY. The season was significant (p<0.01) for all the monthly TDs whereas it was non-significant for FFLMY and FL305MY. The sire was significant (p<0.01) for most of the TDs and FL305MYs except the later TDs (9th, 10th and 11th TD) and FFLMYs. The present investigation revealed the importance of non-genetic factors in performance evaluation of crossbred cattle based on monthly test-day milk yield, FL305MY and FFLMY records.
Milk production is one of the most important economic traits in dairy cattle. Improving milk productivity of Indian cow has been pursued since many decades in India. It is conceded that average yield of an Indian cow is very low, at about 1000 litre/lactation (Dohare
With only 17.67 percent of total bovine population, crossbred cattle contributes 26 per cent of the total milk production in India (BAHS, 2019). During 2018-19, the average milk yield per exotic/crossbred cattle in Punjab (13.43 kg/day) was far above the national average (7.95 kg/day) which describes the importance of crossbred cattle in India and Punjab, in particular.
The main objective of any breed improvement program is to bring about genetic progress by selection of superior sires and dams. The sires are genetically evaluated on the basis of first lactation 305-day milk yield of their daughters at organized farms. The test-day milk yield model accounts for environmental variation specific to individual test-day milk yields and genetic effects associated with individual animals. The estimation of effects of non-genetic parameters on test-day and full lactation milk yields are helpful in predicting selection responses and can be used for further refinement of breeding programmes for overall improvement and genetic gains in organized farms. Accordingly, the present study was done to see the effect of non-genetic factors on first lactation milk yields of crossbred cattle (HF × Sahiwal) maintained at Directorate of Livestock Farms, Guru Angad Dev Veterinary and Animal Sciences University (GADVASU), Ludhiana.
The study was conducted on first lactation monthly test- day milk yield records (4415 Nos.) of 466 crossbred (CB) cattle sired by 89 bulls maintained during 2000 - 2018 (19 years) at Directorate of Livestock Farms, GADVASU, Ludhiana. The crossbred cattle with minimum lactation length of 100 days were considered for the study.
The data were classified and coded according to different season of calving and age at first calving groups for first full lactation milk yield (FFLMY), first lactation 305-day milk yield (FL305MY) and monthly test-day (TD) milk yield records of crossbred cattle.
Season was considered to be one of the main factors of the environment that affects the performance of cattle. There is a wide variation of climatic conditions throughout the year, differences are being more between the seasons and less within a season. Thus, the year was divided into four seasons on the basis of rainfall, temperature and humidity over the years as S-1 (Winter: November to February), S-2 (Summer: March to May), S-3 (Rainy: June-August) and S-4 (Autumn: September-October).
The data were classified into three different groups according to the age at first calving. AFC within a range of mean ± 1 SD was considered group-2 (A-2), >1 SD group-3 (A-3) and <1 SD as group-1 (A-1).
For statistical analysis, SPSS software programme (SPSS, 2013) version 22.0 was used. Mixed model analysis was carried out to study the effects of non-genetic factors on FFLMY, FL305MY and different monthly test day (TD) milk yield (6th, 36th, 306th) records of first lactation crossbred cattle data. The following models were used:
where,
The statistical significance of various fixed effects was determined by ‘F’ test. For significant effects, the differences between pairs of levels of effects were tested by Tukey’s HSD (Honest Significant Difference) test.
The least squares means along with their standard errors (S.E.) for first lactation monthly test day milk yields (TD) have been presented in
The average FL305MY in the present study was 3818.17±103.26 kg (
Traits |
AFC groups |
Season |
Sire |
---|---|---|---|
d.f. |
2 |
3 |
88 |
TD1 |
37.867 |
197.284 * |
28.734* |
TD2 |
50.037 |
320.783* |
33.158* |
TD3 |
6.401 |
279.972* |
27.816* |
TD4 |
18.418 |
363.429* |
32.807* |
TD5 |
19.307 |
326.053* |
32.988* |
TD6 |
4.767 |
168.586* |
28.523* |
TD7 |
2.701 |
80.963* |
22.797** |
TD8 |
11.717 |
66.992* |
17.697** |
TD9 |
6.242 |
74.801* |
17.626 |
TD10 |
14.079 |
73.690* |
18.324 |
TD11 |
17.144 |
69.061* |
16.802 |
FL305DMY |
816310.599 |
1624287.009 |
1607818.903** |
FFLDMY |
17058089.652* |
966064.014 |
4291118.505 |
*significant at 1% (p≤0.01); **significant at 5% (p≤0.05).
No of observations |
FL305DMY Mean ± SE (kg) |
FFLDMY Mean ± SE (kg) |
|
---|---|---|---|
466 |
3818.17±103.26 |
4979.60±184.45 |
|
S-1 |
173 |
3924.67ab±125.32 |
5021.80±223.86 |
S-2 |
123 |
3691.04ab±136.25 |
5063.72±243.37 |
S-3 |
108 |
3704.96a±139.65 |
4825.07±249.46 |
S-4 |
62 |
3952.00b±185.11 |
5007.81±330.64 |
A-1 |
50 |
3726.33±185.19 |
5341.26b±330.80 |
A-2 |
360 |
3753.63± 100.52 |
4490.94a± 179.55 |
A-3 |
56 |
3974.54±174.93 |
5106.59ab±312.46 |
Means |
with different |
superscripts within |
a column differ |
Means with different superscripts within a column differ significantly.
The effect of season of calving was highly significant (P<0.01) on all the monthly test-day milk yields (
Overall, non-significant effect of season of calving was observed for FFLMY and FL305MY. However, there was significant difference between rainy and autumn calvers. Manoj
The effects of different groups of age at first calving on monthly test day milk yields was non- significant. However, Dongre
For FFLMYs, the effect of AFC was significant (P < 0.01); whereas it was non-significant for FL305MY in the present study. Wondifraw
Means with different superscripts within a column differ significantly.
Means with different superscripts within a row differ significantly.
Highly Significant (p<0.01) effect of sire was observed for early TDs (TD-1 to TD-6), significant (p<0.05) effect for the mid lactation TDs (TD-7 & TD-8) and non-significant for rest of the test days. The sire effect was significant (p<0.05) for FL305MY whereas it was non-significant for FFLMY. Singh and Gurnani (2004) reported a significant (P<0.01) effect of sire on FL305MY in Karan Fries and Karan Swiss cattle. In Jersey crossbred, Ratwan
The monthly test-day milk yields were significantly influenced by season of calving. Significant influence of environmental components on milk production traits elucidates the importance of non-genetic parameters in breeding programmes for genetic improvement of crossbred cattle through selection. The effect of sire was significant for most of test-day milk yields suggesting the use of superior sires for improvement of milk production traits in dairy cattle.