HERITABILITY AND REPETIBILITY OF MILK PRODUCTION AND CALVING INTERVAL IN A HOLSTEIN HERD, 2000.
Three hundred and ninety records of Holstein cows from Doña Evita Farm were utilized to estimate heritability and repetibility of milk production and calving interval. The farm is located in Volcan, Chiriqui, Panama at 1,080 meter over the sea level with 6,597 mm of precipitation. The average annual temperature is 23°C and 82% is the average humidity. All cows received similar nutrition and health programs. Cows pastured fertilized Brachiaria decumbens and Cynodon nlemfuensis. pennisetum purpureum CV Taiwan was the cut pasture. Daily every cow received 4.1 kg of concentrate (20% CP and 2.5 Mcal ME/kg DM). Also, corn silage and mineralized salt was supplied daily ad libitum. Dependent variables were milk production (MY), calving interval (CI) and milk production calving interval ratio (MY/CI). Data were analyzed using a generalized lineal model which included effects of number of lactations (NL) and year-season calving (YSC) and lactation length (LL) was the covariance. Variance components were estimated according to the full and half sib genetic model with unequal number of observation in the subclass. Heritability and repetibility were estimated according to Becker (1984) methodology. NL, YSC and LL were highly significant (P<0.01) for MY but NL and LL were not significant (P>0.05) for CI. On the other hand, NL was significant (P<0.05), YSC was highly significant (P<0.01) and LL was not significant (P>0.05) for MY/CI ratio. Coefficient of variation were 17.2%, 14.1% and 24.3% for MY, CI and MY/CI ratio, respectively. Heritability and standard error for MY, CI and MY/CI ratio were 0.18 ± 0.13; 0.16 ± 0.15 and 0.29 ± 0.17, respectively. Repetibility and standard error was 0.18 ± 0.07 for MY; 0,20 ± 0.07 for CI; and 0.12 ± 0.07 for MY/CI ratio. Values of heritability and repetibility are in agreement with previous works and were highly influenced by environmental factors.
| Main Authors: | , |
|---|---|
| Format: | Digital revista |
| Language: | spa |
| Published: |
Instituto de Innovación Agropecuaria de Panamá
2002
|
| Online Access: | http://www.revistacienciaagropecuaria.ac.pa/index.php/ciencia-agropecuaria/article/view/374 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|