Effects of Crude Protein Levels in Total Mixed Rations on Growth Performance and Meat Quality in Growing Korean Black Goats

Abstract

This study was carried out to investigate effects of crude protein (CP) levels in total mixed rations (TMR) on growth performance and meat quality in growing Korean black goats. Thirty-six 6-month-old growing black male goats (initial body weight = 17.95±0.13 kg) were used. The goats were randomly divided into four treatments and 9 animals were allotted to each treatment. In terms of treatments, CP levels in TMR were 14, 16, 18, and 20% of dry matter (DM) and all diets were isocaloric (2.4 Mcal ME/kg DM). The experiment lasted for 20 weeks with a 15-day adaptation period. After the end of the trial, five goats from each treatment were slaughtered to measure carcass characteristics and meat quality. Average daily gain (ADG) significantly (p<0.05) increased as dietary CP levels increased, but the highest ADG was found on the 18% CP treatment. The higher CP levels in TMR significantly (p<0.05) decreased feed conversion ratio, but the lowest ratio was on the 18% CP treatment, suggesting a higher bioavailability of nutrients by balanced energy and protein levels on this treatment. There was no significant difference in dressing percentage among treatments, but there was a tendency for levels more than 16% CP in TMR to have a comparatively higher dressing percentage than the 14% treatment. The percentages of meat, fat and bone were not significantly influenced by dietary CP levels. Dietary CP levels did not influence chemical composition of goat meat. Furthermore, there was no significant difference among treatments in any of the sensory parameters except for tenderness. Tenderness was similar for 18 and 20% treatments, which were significantly (p<0.05) higher than the 14% treatment. The results from this study suggested that an adequate CP level in TMR for achieving optimal growth performance and meat quality of growing Korean black goats might be 18% of DM, and that dietary CP level above 18% seemed not to further increase growth performance and meat quality.

Effects of levels of crude protein and ground corn cobs in total mixed ration on intake, rumen fermentation and milk production in crossbred Holstein Friesian lactating dairy cows

“…Similarly, in this study showed that there was significant difference in daily total DM intake among treatments. The result from present study was similar to those from Broderick (2003) who reported that feed intake of DM was lower on 15.1% CP than at 16.7% and 18.4% CP and earlier studies reported that daily CP intake increased as CP level in feed increased (Hwangbo et al 2009). Means in the same row with different superscripts differ (P < 0.05).…”

“…Daily total DM intake ranged from 10.2 to 14.3 kg/d and dairy CP and organic matter (OM) intake significantly increased with increasing dietary CP level (P < 0.05). In general, it is well known that feed intake increases as dietary CP level increases (Argüello et al 2003;Broderick & Reynal 2009;Hwangbo et al 2009). Similarly, in this study showed that there was significant difference in daily total DM intake among treatments.…”

“…It has been well known that total mixed rations (TMRs) improve nutrient utilisation due to balance intakes for roughage and concentrates leading to stabilisation of ruminal fermentation (Argüello et al 2003;Broderick 2003;Hwangbo et al 2009). Taking this into account, in order to maximise cows' performance and ruminal fermentation (Orskov 1999), the determination of optimal protein levels in TMR feeding system especially in tropical area is indispensable.…”

Response of growing ruminants to diet in warm climates: a meta-analysis

“…Lammers and Heinrich (2000) fed heifers ration with LP, MP and HP and reported that ADG was improved by 9% in heifers fed a diet containing HP-to-ME ratio. The same results were observed in sheep and goats (Hwangbo et al, 2009;Sultan et al, 2010). Increasing dietary CP levels causes a change in the process of intake and digestion in the rumen and also improves absorption of by-pass proteins that contribute to metabolisable protein available for growth (Nolan and Leng, 1983).…”

Effectiveness of High Input Feeding System in Relation to Growth and Carcass Quality of Various Classes of Beetal Kids

“…The castration at 4 mo age resulted in lower glycogen content which may be responsible for lower hue angle value (Ripoll et al, 2008). Higher value of drip loss in S2 group was due to lower water holding capacity of meat as water holding capacity was decreased due to lower growth performance of the S2 (Hwangbo et al, 2009). Other carcass attributes showed the non-significant effect of the class of animals because the sex and castration did not result in fat deposition at this age of animals and could be due to fattening period was less than 5 months (Zamiri et al, 2012).…”