Estimates of genetic and crossbreeding parameters for milk components and potential yield of dairy products from New Zealand dairy cattle

Figures & data

Table 1. Lactation yields of milk and milk product potentials from Holstein-Friesian (HF), Jersey (J) and crossbred (HF×J) first lactation heifers and standard errors (SE).

	HF		HF×J		J		Breed effect			Heterosis
	Mean	SE	Mean	SE	Mean	SE	HF×J	SE	P-value	HF×J	SE	P-value
Days in milk	212^b	1.81	214^a	1.71	213^ab	1.94	−1.78	1.58	0.264	1.97	1.30	0.130
Milk yield (kg)	3121.8^a	48.3	2947.0^b	45.7	2751.6^c	51.7	633.3	41.5	<.001	93.6	34.2	0.006
Fat yield (kg)	142.9^c	2.25	149.9^a	2.13	147.0^b	2.41	−1.00	1.96	0.610	11.8	1.62	<.001
Protein yield (kg)	113.6^a	1.69	112.3^a	1.59	107.7^b	1.80	12.5	1.46	<.001	5.86	1.20	<.001
Lactose yield (kg)	160.0^a	2.47	151.6^b	2.34	142.0^c	2.64	30.9	2.12	<.001	5.06	1.75	0.004
Fat percentage	4.63^c	0.05	5.11^b	0.05	5.38^a	0.06	−1.09	0.04	<.001	0.16	0.04	<.001
Protein percentage	3.70^c	0.02	3.86^b	0.02	3.97^a	0.02	−0.39	0.02	<.001	0.05	0.02	0.002
Lactose percentage	4.86^c	0.01	4.88^b	0.01	4.89^a	0.01	−0.05	0.01	<.001	0.01	0.01	0.942
Protein-to-protein-plus-lactose	0.42^a	0.002	0.43^b	0.002	0.44^c	0.002	−0.02	0.001	<.001	0.003	0.001	0.002
Somatic cell score	5.89	0.09	5.92	0.09	5.87	0.11	0.01	0.08	0.936	0.07	0.07	0.325
Whole milk powder	347.6^a	6.08	316.6^b	5.75	290.2^c	6.51	92.6	5.20	<.001	4.74	4.29	0.26
Skim milk powder	232.0^a	4.09	210.9^b	3.87	193.1^c	4.38	62.7	3.49	<.001	2.94	2.88	0.308
Butter	168.8^b	2.84	179.1^a	2.68	176.3^a	3.04	26.1	4.86	<.001	25.4	4.01	<.001
Cheese	358.9^b	5.60	364.9^a	5.30	351.6^b	5.99	−4.86	2.47	0.049	15.3	2.04	<.001

^a,b,cMeans with different letters denote significant differences (P < 0.05).

Table 2. Estimates of variance components and heritabilities (h²) with their associated standard errors of the mean for total lactation milk production traits and milk product potential.

				h^2
Milk yield	51898	172367	224270	0.23±0.04
Fat yield	74.1	420.2	494.4	0.15±0.04
Protein yield	39.2	232.4	271.6	0.14±0.03
Lactose yield	129.3	459.0	588.4	0.22±0.04
Fat percentage	0.13	0.15	0.28	0.45±0.06
Protein percentage	0.02	0.03	0.05	0.40±0.05
Lactose percentage	0.005	0.008	0.013	0.35±0.05
Protein-to-protein-plus-lactose	0.0001	0.0002	0.0003	0.42±0.06
Whole milk powder	1096	2497	3293	0.31±0.05
Skim milk powder	503	1125	1627	0.31±0.04
Butter	124.5	656.4	780.9	0.16±0.04
Cheese	390.8	2618	3009	0.13±0.03

Notes: , animal additive genetic variance, , residual error variance;, sum of all variances.

Table 3. Estimates of genetic and phenotypic correlations and standard errors for total lactation yields of milk production traits and estimated milk product potential.

	Milk yield	Fat yield	Protein yield	Lactose yield	Fat percentage	Protein percentage	Lactose percentage	Protein-to-protein-plus-lactose	Whole milk powder	Skim milk powder	Butter	Cheese
Milk yield		0.75±0.01	0.92±0.01	0.99±0.01	−0.38±0.01	−0.34±0.01	−0.08±0.02	−0.26±0.02	0.94±0.01	0.93±0.01	0.70±0.01	0.85±0.01
Fat yield	0.42±0.12		0.84±0.01	0.73±0.01	0.30±0.01	0.08±0.02	−0.09±0.02	0.13±0.02	0.57±0.01	0.56±0.01	0.99±0.01	0.90±0.01
Protein yield	0.86±0.04	0.53±0.11		0.91±0.01	−0.15±0.02	0.03±0.02^ns	−0.08±0.02	0.07±0.02	0.77±0.01	0.77±0.01	0.81±0.01	0.95±0.01
Lactose yield	0.98±0.01	0.39±0.12	0.82±0.11		−0.38±0.01	−0.34±0.01	0.07±0.02	−0.32±0.01	0.96±0.01	0.96±0.01	0.69 ±0.01	0.84±0.01
Fat percentage	−0.67±0.08	0.37±0.12	−0.45±0.01	−0.68±0.08		0.64±0.01	−0.04±0.02	0.60±0.01	−0.54±0.01	−0.54±0.01	0.36±0.01	0.01±0.02^ns
Protein percentage	−0.69±0.08	−0.10±0.14^ns	−0.24±0.14	−0.72±0.08	0.63±0.06		−0.02±0.02^ns	0.92±0.01	−0.54±0.01	−0.55±0.01	0.13±0.02	0.09±0.02
Lactose percentage	−0.16±0.12	−0.19±0.14	−0.29±0.13	0.03±0.13^ns	0.01±0.11^ns	−0.08±0.11		−0.39±0.01	0.16±0.02	0.17±0.02	−0.10±0.02	−0.08±0.02
Protein-to-protein-plus-lactose	−0.58±0.09	−0.03±0.14^ns	−0.13±0.14	−0.68±0.08	0.58±0.07	0.94±0.01	−0.41±0.09		−0.54±0.01	−0.55±0.01	0.17±0.02	0.13±0.02
Whole milk powder	0.93±0.02	0.24±0.13	0.66±0.08	0.97±0.01	−0.74±0.06	−0.84±0.05	0.14±0.11	−0.82±0.05		0.99±0.01	0.52±0.01	0.69±0.01
Skim milk powder	0.93±0.02	0.24±0.13	0.65±0.08	0.97±0.01	−0.74±0.06	−0.84±0.05	0.15±0.11	−0.83±0.05	0.99±0.01		0.51±0.01	0.88±0.01
Butter	0.33±0.13	0.99±0.01	0.46±0.12	0.30±0.13	0.46±0.11	−0.03±0.14	−0.16±0.13	0.02±0.13^ns	0.16±0.14	0.15±0.14		0.88±0.01
Cheese	0.72±0.01	0.76±0.07	0.92±0.03	0.68±0.08	−0.15±0.14	−0.11±0.14^ns	−0.22±0.14	−0.02±0.14^ns	0.50±0.11	0.72±0.07	0.50±0.01

Notes: Genetic correlations shown below the diagonal and phenotypic above. ns, non-significant correlations (P > 0.05) all other correlations are significantly different to zero (P < 0.05).