MATERIALS AND METHODS

The experiment was carried out during the month of August 2007 and January 2008. The present trial was undertaken to assess the utilization of an herbal galactogogue (Table 1) on milk yield and quality of low production cows.

Table 1:	Herbal galactogogue mixture composition

Multiparous (n = 12, average 4.5 years of age and 450 kg of weight) producing a mean of 15.5 L day^-1 were selected. Cows were mechanically milked at 500 and 1500 h daily. The feed consisted in a commercial compound with 17% crude protein and 2,800 Kcal of EM kg^-1 and was offered at a rate of 1 kg per 5 L of liquid milk. The fiber was obtained from corn stalk with no grain, supplied for ad libitum intake. Clean and fresh water was always available for consumption from an automatic waterer. Two hundred milligrams of the herbal galactogogue mixture (Table 1) was administered via the feed.

Milk yield was recorded for five months and was proportionately sampled to test for quality (density, total solids, pH, fat and protein) using ultrasound (Milk analyzer; SACCO^®). The milk samples were assessed in duplicate. Data were statistically analyzed using the SAS package.

RESULTS

Milk yield with the herbal galactogogue was increased 8.5% (p<0.05; 16.94 vs. 15.62 L, respectively), these values are quite similar to those observed in Los Altos de Jalisco México for Holstein cows. On the other hand, total solids in milk presented a 5% reduction (p<0.05; 10.99 vs. 11.55%, respectively). Total casein averaged 2.5% and was similar among treatments (p>0.05; 2.53 vs. 2.56%, herbal extract and control, respectively), hence the daily production was not changed (p>0.05; 47.5 vs. 46.99 g day^-1, respectively). The annual casein production (305 days) was 14.45 kg in average. Milk protein percent was 3.18 and 3.30 for the herbal galactogogue and control (p>0.05) with similar statistical value. Furthermore, the daily yield was similar (p>0.05; 59.9 vs. 59.81 g day^-1, respectively. Same tendency was observed in the present trial on protein percent.

Milk density was slightly higher with the galactogogue (p<0.05; 1.0321 vs. 1.0309 g cm^-3). A 12% reduction on the milk pH was observed with the product tested (p<0.05; 6.31 and 7.17). Total fat in milk averaged 2.37% and reduced 21% with the use of the herbal galactogogue (p<0.05; 2.24 vs. 2.83%, respectively). The fat yield was dimished in 15% (p>0.05; 44.43 vs. 52.01 g day^-1, respectively). The free fatty acid content in the milk was increased in 52% with the herbal extract (p<0.05; 0.34 vs. 0.16%, respectively). Lactose was increased with the herbal extract (p<0.05; 4.63 vs. 4.87%, respectively). Also, the somatic cell count was reduced. Base on the results of the present study, it is concluded that there is a small positive effect of a mixture of sterols and essential oils on the production and quality of low producing cows.

DISCUSSION

With the use of the herbal galactogogue the milk production was augmented 1.32 kg day^-1. Olivo et al. (2005) in agro-forestry production systems reported an increase of 9 to 11.5 kg of milk with the utilization of plant extract herbals. This may be related to the essential oils present in the herbal mixture used. Soltan et al. (2009) using four levels of essential oils in the drinking water, did not affected milk yield.

Furthermore, in the present trial the daily yield of milk protein was similar among treatments and averaged 59.85 g. Olivo et al. (2005) observed a decrease on the protein content with an herbal galactogogue in the cow feed. In the other hand, Olivo et al. (2005) observed a reduction on the milk fat (from 3.29 to 3.18%), but lactose percent was increased with the herbal extract, similar observation was reported by Olivo et al. (2005). Kung et al. (2008) using high producing cows fed corn silage in the diet and two essential oil mixture produced 2.7 kg more milk. Spanghero et al. (2009) adding encapsulated essential oil (0, 320, 640 and 960 mg day^-1) to fresh cows observed no effect on milk and milk component yields. Tassoul and Shaver (2009) with the supplementation of 1200 mg of essential oils mixture/cow per day reported no effect on milk yield or composition. The results of the authors are in accordance with the observations of the present study where milk production or composition was substantially unaffected.

Benchaar et al. (2006, 2007) using a mixture of essential oil, reported no effect on milk production or composition in cows fed either corn or alfalfa silage. Furthermore, Kung et al. (2008) with two mixtures and a corn silage based diet, observed that the percentages of milk fat and protein, as well as the somatic cell count were not affected. Soltan et al. (2009) adding the essential oils in the drinking water reported varying effect on milk composition and yield. The previous results showed that the small doses of essential oils obtained from herbals have small insignificant effect on milk yield or composition. These findings are similar to the observation of the present trial, where no change was detected in nutrients or production of milk.

Base on the results of the present study, it is concluded that there is a small positive effect of a mixture of sterols and essential oils on the production and quality of low producing cows.