The effects of feeding high concentrations of molasses and supplementing with nitrogen and unprotected tallow on intake and performance of dairy cows

Abstract

A series of three replicated 3 × 3 Latin-square design experiments was carried out with lactating dairy cows (15 in experiments 1 and 3, and 18 in experiment 2). The objectives of these experiments were to investigate if the feeding of high concentrations of molasses would be detrimental to the performance or health of cows, and if the strategic supplementation of nitrogen or unprotected fat could enhance the efficiency of molasses feeding. In experiment 1, complete diets were based on grass silage with three inclusion rates of a liquid molasses-based supplement (Molaferm 20) to supply molasses dry matter (DM) of 125, 250 and 375 g/kg DM respectively. In experiment 2, the control diet contained (g/kg DM) 460 grass silage, 310 'molaferm 20' and 192 barley and 22 soya-bean meal, and was then supplemented with urea (12 g/kg DM) or soya-bean meal (177 g/kg DM). In experiment 3, the control diet was based on (g/kg DM) grass silage (460), molaferm 20 (310), barley (130), soya-bean meal (65) and oatfeed (20). Two concentrations, low and high, of unprotected tallow were added to the control diet (12·5 and 25·8 g/kg DM, respectively).In experiment 1, cows suffered from some scouring on the highest molasses treatment, but recovered when changed to either the medium or low molasses treatment. However, there were no clinical symptoms of ill health observed during experiments 2 and 3. In experiment 1, animal intake and performance on the diets containing molasses DM of 125, 250 and 375 g/kg DM respectively were: total DM intake, 12·8, 16·2 and 18·6 kg/day (s.e.d. 1·03, P < 0·001); milk yield, 15·5,17·4 and 17·6 kg/day (s.e.d. 0·53, low v. medium or high, P < 0·01); fat concentration, 39·6, 39·7 and 40·0g/kg (s.e.d. 0·70, P>0·05); protein concentration, 31·6, 32·7 and 33·6g/kg (s.e.d. 0·22, P < 0·05). In experiment 2, supplementation of the control diet both with urea and soya-bean meal significantly increased DM intake (P < 0·01); milk yield (P < 0·01) and protein concentration in milk (P < 0·05), but had no significant effects on fat concentration in milk (P > 0·05). In experiment 3, there were no significant differences in DM intake between the three treatments. However, supplementation with both low and high concentrations of unprotected tallow significantly increased milk yield (P < 0·01) and significantly decreased fat (P < 0·01) and protein (P < 0·001) concentrations in milk.It is concluded that lactating dairy cows could be given molasses up to 250 g/kg DM in grass silage-based complete diets without adverse effects on milk production or health. When a diet contained a high concentration of molasses (248 g/kg DM), supplementation with urea and soya-bean meal increased intake and milk production, and supplementation with unprotected tallow also increased milk yield, but fat and protein concentrations in milk were decreased.

The soybean molasses in diets for dairy cows

“…The our results differ from the conclusions of Yan et al (1997) who reported that increase of the content of molasses in the lactating The cows fed soybean molasses supplemented ration had a higher milk protein concentration and yield relative to cows from control group (3.92 and 8.64 %, respectively), (P˂0.01). By including soybean molasses into ration the portion of readily degradable fractions of carbohydrates in rumen increases, which is likely to contribute to better energy supply of microorganisms and consequently higher rate of microbial protein synthesis from available non-protein nitrogen.…”

Offering soybean molasses adsorbed to agricultural by‐products improved lactation performance through modulating plasma metabolic enzyme pool of lactating cows

“…Similar results were reported by Yan et al. ( 1997 ) that when the inclusion rate of molasses increased from 156 to 468 g/kg, DM improved milk protein concentration from 31.6 to 33.6 g/kg for mid‐lactation cows. Keady and Murphy ( 1998 ) observed that supplementing sucrose (10 g/kg DM) significantly increased milk protein concentration of lactating dairy cows.…”

Effect of soybean molasses-adsorbents on in vitro ruminal fermentation characteristics, milk production performance in lactating dairy cows

“…Yan et al (1997) demonstrated that when molasses inclusion in the diets fed to mid-lactation cows increased from 156 to 468 g/kg DM, milk protein concentration increased from 31.6 to 33.6 g/kg. Keady and Murphy (1998) observed that supplementing sucrose (10 g/kg DM) significantly increased milk protein concentration of lactating dairy cows.…”