Intra-annual variation in feed and milk composition in smallholder dairy farms in Kenya

Figures & data

Table 1. Characteristics of sampled smallholder dairy farms in Nakuru county (in percentage).

		UL (n = 14)	MRL (n = 17)	ERL (n = 19)	Average (n = 50)
Herd sizes	Small (less than 10 cows)	21.4	58.8	78.9	56.0
	Medium (11-30 cows)	7.1	17.6	15.8	14.0
	Large over 30 cattle	71.4	23.5	5.3	30.0
Breed	Holstein-Friesians and its crosses	35.7	52.9	63.2	52.0
	Ayrshire and its crosses	64.3	41.2	36.8	46.0
	Local breeds	0.0	5.9	0.0	2.0
Farm size	Small (less than 5 acres [2.02 Ha])	14.3	64.3	94.7	62.0
	Medium (50-10 acres [2.02-4.04 Ha])	21.4	17.6	5.3	14.0
	Large (over 10 acres [4.04 Ha])	64.3	17.6	0.0	24.0
Milk prices (Ksh)	Rainy season	40-50	30-35	26-30	-
	Dry season	50-70	35-45	30-40	-
UL-urban locations, MRL-mid rural locations and ERL-extreeme rural location 1 Kenyan Shilling (Ksh) = 0.0088 United States Dollar

Table 2. Feed resources available for cattle in smallholder dairy farms in Nakuru county (discussions with 43 farmers).

	Long Rainy Season			Short Dry Season			Short Rainy Season			Long Dry Season
Feed type	April	May	June	July	August	September	October	November	December	January	February	March
Natural pastures (local grasses)	√	√	√	√			√	√	√
Napier grass	√	√	√	√			√	√
Maize silage				√	√	√			√	√	√	√
Crop residues (maize and bean stover)				√	√	√	√	√	√	√
Concentrates (dairy meal)	√	√	√	√	√	√	√	√	√	√	√	√
Total and partly mixed rations (TMR)	√	√	√	√	√	√	√	√	√	√	√	√

Table 3. Feed chemical composition across the different seasons in smallholder dairy farms in Nakuru county (mean ± standard deviation).

	Season	LDS ^a	LWS ^b	SDS ^c	SWS ^d	Average	Pr(>F)
CP (%DM)	Grasses	13.5 ± 5.9	13.6 ± 5.6	15.2 ± 5.2 ^d	11.2 ± 5.1	13.4 ± 5.5	0.00 **
	Napier grass	9.6 ± 5.7	15.0 ± 6.0	12.6 ± 5.7	12.1 ± 8.0	12.0 ± 6.4	0.37
	Maize silage	11.4 ± 4.9	11.7 ± 3.0	11.4 ± 1.5	11.3 ± 3.3	11.4 ± 3.3	0.99
	Maize stover	7.9 ± 2.4	7.1 ± 2.3	8.8 ± 4.6	10.3 ± 3.7	8.7 ± 3.3	0.15
	Dairy meal	15.9 ± 3.0	15.9 ± 5.0	19.2 ± 4.7	17.7 ± 3.5	17.4 ± 3.9	0.14
	TMR	13.4 ± 4.4	13.9 ± 4.8	14.5 ± 4.9	12.4 ± 4.7	13.4 ± 4.7	0.19
ME (%DM)	Grasses	7.4 ± 0.8	7.2 ± 0.8	7.4 ± 0.8	7.0 ± 1.0	7.3 ± 0.9	0.15
	Napier grass	6.7 ± 0.5	7.2 ± 0.4	7.1 ± 0.2	7.3 ± 0.7	7.0 ± 0.5	0.09
	Maize silage	7.3 ± 0.6	6.9 ± 0.7	6.7 ± 0.3	7.1 ± 0.7	7.0 ± 0.6	0.39
	Maize stover	6.8 ± 0.8	6.7 ± 0.4	7.3 ± 0.6	7.3 ± 0.8	7.0 ± 0.8	0.25
	Dairy meal	8.9 ± 0.8	8.1 ± 1.1	9.0 ± 0.6	9.1 ± 0.7	8.9 ± 0.8	0.11
	TMR	7.9 ± 1.0	7.5 ± 1.2	7.8 ± 1.0	7.7 ± 1.1	7.7 ± 1.1	0.47
OM (%DM)	Grasses	83.3 ± 3.9	80.8 ± 3.3	83.1 ± 4.2	83.3 ± 5.0	82.9 ± 4.4	0.10
	Napier grass	77.6 ± 5.5	79.9 ± 3.9	80.7 ± 1.3	78.9 ± 4.1	78.8 ± 4.5	0.70
	Maize silage e	88.2 ± 2.1	86.0 ± 4.7	83.2 ± 3.8	86.9 ± 2.5	86.4 ± 3.4	0.07
	Maize stover	88.5 ± 3.8	88.1 ± 4.6	88.0 ± 3.6	88.1 ± 3.0	88.3 ± 3.5	0.99
	Dairy meal	88.4 ± 6.1	86.5 ± 5.0	88.5 ± 10.8	89.8 ± 3.0	88.9 ± 6.2	0.78
	TMR	88.1 ± 4.4	86.1 ± 4.7	87.5 ± 4.7	86.9 ± 4.8	87.2 ± 4.7	0.27
NDF (%DM)	Grasses	61.1 ± 6.8	61.6 ± 7.2	59.2 ± 7.9	64.8 ± 8.2 ^c	61.7 ± 8.0	0.00 **
	Napier grass	60.7 ± 4.5	61.0 ± 3.4	58.7 ± 3.2	60.7 ± 4.5	60.6 ± 4.0	0.91
	Maize silage	51.0 ± 9.3	56.0 ± 8.1	65.3 ± 9.8	55.7 ± 10.7	56.4 ± 10.5	0.14
	Maize stover	79.2 ± 8.3	82.2 ± 6.7	75.5 ± 8.6	79.1 ± 8.7	79.1 ± 8.2	0.57
	Dairy meal	41.4 ± 8.3	38.1 ± 4.5	40.4 ± 8.9	41.1 ± 6.5	40.8 ± 7.3	0.87
	TMR	59.2 ± 14.5	62.7 ± 16.1	58.1 ± 17.1	60.6 ± 13.7	60.1 ± 15.1	0.62
ADF (%DM)	Grasses	30.8 ± 8.2	31.5 ± 6.6	31.2 ± 9.2	33.5 ± 9.2	31.9 ± 8.7	0.41
	Napier grass	42.7 ± 5.5	38.3 ± 5.5	36.7 ± 6.8	36.4 ± 7.7	39.4 ± 6.4	0.17
	Maize silage	28.2 ± 5.3	31.8 ± 10.2	42.1 ± 7.9	34.1 ± 8.9	33.8 ± 8.9	0.05
	Maize stover	39.6 ± 10.7	40.3 ± 5.6	35.0 ± 8.3	36.0 ± 7.9	37.9 ± 8.9	0.53
	Dairy meal	18.5 ± 6.2	20.3 ± 1.1	17.8 ± 3.8	18.1 ± 6.2	18.3 ± 5.4	0.88
	TMR	27.5 ± 8.7	29.3 ± 10.7	29.1 ± 10.6	31.3 ± 12.2	29.5 ± 10.8	0.38
ADL (%DM)	Grasses	5.5 ± 1.1	5.8 ± 0.9	5.7 ± 1.6	5.9 ± 1.5	5.8 ± 1.4	0.72
	Napier grass	3.5 ± 2.2	2.7 ± 0.7	2.9 ± 0.9	3.8 ± 1.5	3.3 ± 1.6	0.63
	Maize silage	5.9 ± 1.1	7.4 ± 1.7	7.5 ± 1.3	6.8 ± 1.8	6.8 ± 1.5	0.26
	Maize stover	5.3 ± 2.6	4.8 ± 1.4	3.6 ± 1.8	4.2 ± 2.0	4.6 ± 2.2	0.33
	Dairy meal	5.1 ± 1.2	6.2 ± 0.8	5.3 ± 1.7	4.9 ± 1.3	5.1 ± 1.4	0.38
	TMR	5.2 ± 2.1	5.5 ± 2.1	5.4 ± 1.8	5.7 ± 2.5	5.4 ± 2.2	0.75

CP – crude protein, ME – metabolisable energy, NDF – neutral detergent fibre, OM – organic matter, ADF – acid detergent fibre, ADL – acid detergent lignin, TMR – total mixed rations, LDS – long dry season (January, February and March), LWS – long wet season (April, May, June), SDS – short dry season (July, August and September), SWS – short wet season (October, November and December). Significance: “***”P < 0.001, P< “**” 0.01, P< “*” 0.05

Table 4. Mixed model analysis results showing effects of feed type, season and feed type–season interaction in smallholder dairy farms in Nakuru county.

	Feed type	Season	Feed: Season
	Pr(>Chisq)	Pr(>Chisq)	Pr(>Chisq)
CP	0.00***	0.22	0.47
ME	0.00***	0.38	0.51
NDF	0.00***	0.74	0.81
OM	0.00***	0.33	0.53
ADF	0.00***	0.98	0.38
ADL	0.00***	0.86	0.63

CP – crude protein, ME – metabolisable energy, NDF – neutral detergent fibre, OM – organic matter, ADF – acid detergent fibre, ADL – acid detergent lignin. Significance: “***”P < 0.001, “**” P < 0.01, “*” P < 0.05

Table 5. Milk physicochemical composition (arithmetic mean and standard deviation) across seasons in dairy farms in Nakuru county.

	LDS ^a	LWS ^b	SDS ^c	SWS ^d	Average	p-value
Butter fat	3.7 ± 0.9	3.5 ± 1.0	3.6 ± 0.8	3.5 ± 0.8	3.6 ± 0.9	0.103
Protein	3.5 ± 0.3	3.6 ± 0.3 ^c	3.5 ± 0.3	3.5 ± 0.3	3.5 ± 0.3	0.02 *
Solid not fats	9.2 ± 0.9	9.5 ± 0.7 ^c,d	9.2 ± 0.8	9.2 ± 0.9	9.2 ± 0.8	0.00**
Density	1.031 ± 0.004	1.032 ± 0.003 ^a,c	1.031 ± 0.004	1.031 ± 0.004	1.031 ± 0.004	0.02 *
Freezing point	−0.60 ± 0.07	−0.62 ± 0.05 ^a,c	−0.6 ± 0.0	−0.6 ± 0.05	−0.60 ± 0.06	0.01 **
Total solids	13.0 ± 1.4	13.0 ± 1.2	12.8 ± 1.2	12.7 ± 1.2	12.8 ± 1.2	0.11
Fat: protein ratio	1.2 ± 0.5	1.1 ± 0.4	1.2 ± 0.5	1.1 ± 0.4	1.1 ± 0.4	0.03*

Kenya dairy standards (KeBS) define butterfat must be not less than 3.25%, protein must be not less than 3.5%, solid not fats must not be less than 8.50%, density 1.028-1.036 g/ml, and the freezing point should range between −0.525- 0.550 °C. LDS-long dry season (January, February and March), LWS – long wet season (April, May, June), SDS – short dry season (July, August and September), SWS – short wet season (October, November and December). Significance: “***”P < 0.001, “**” P < 0.01, “*” P < 0.05

Table 6. Mixed model analysis showing effects of season, farming system, and season-farming system interaction on the milk physicochemical composition of milk samples from dairy farms in Nakuru county.

	Season Pr(>F)	Farming System Pr(>F)	Season: Farming System Pr(>F)
Butterfat (%)	0.09	0.90	0.01 **
Protein (%)	0.02*	0.34	0.28
Solid not fats (%)	0.00**	0.39	0.52
Density g/ml	0.01 *	0.51	0.24
Freezing point °C	0.01**	0.47	0.30
Total solids (%)	0.09	0.58	0.12
Fat: protein ratio	0.01 *	0.90	0.00 **

Farming systems included intensive urban farming systems, semi-intensive farming systems and extensive rural farming systems. Significance: “***”P < 0.001, “**” P < 0.01, “*” P < 0.0