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A Pragmatic Challenge of Total Mixed Ration: Time to Contemplate Component Feeding
The objective of this research was to establish prolonged effects of total mixed ration (TMR) vs. component feeding (CF) in high-producing lactating dairy cows in a competitive environment. Twelve multiparous (650 ± 55 kg body weight; 45 ± 20 days in milk; mean ± SD) and twelve primiparous (579 ± 49 kg body weight; 59 ± 36 days in milk) lactating Holstein cows in free group yards were monitored continuously in a completely randomized design experiment for three months. A 10-d pre-trial adaptation period was allowed before sampling and data collection. Cows were offered an experimental diet (barley grain and corn silage-alfalfa hay-based) as either TMR or CF of forage and concentrate for the entire experiment. The forage to concentrate ratio on a dry matter basis was 50:50, allowing 5-10% daily orts. Cows were fed 3 times daily at 0530, 1330, and 2130 h. Cows were milked three times daily. The daily TMR was divided to three same portions and each portion was fed at each feed delivery. The CF was divided to one portion of forage fed at 0530 h, and two same portions of concentrate fed at 1330 and 2130 h. Statistical data analysis was conducted with Mixed Models composed of fixed (treatment, parity and their interaction) and random (cow within treatment by parity and residuals) effects. Feeding TMR vs. CF did not affect (P>0.15) dry matter intake (21.7 vs. 22.0 kg/d) and milk yield (34.0 vs. 34.5 kg/d). However, feeding CF instead of TMR improved milk content of fat (3.6 vs. 3.3%) and protein (3.3 vs. 3.1%). As a result, milk protein and fat yields were increased by offering CF vs. TMR (P<0.05). Daily duration of eating (350 vs. 330 min/d), ruminating (320 vs. 330 min/d), and total chewing (670 vs. 660 min/d) were similar (P>0.50) between TMR and CF cows, respectively. The first meal length (FML), starting from feed delivery until the first non-eating bout of ≥20 min, was 175 min in the TMR cows vs. 201 min in the CF cows (P<0.01). Urine (8.1 vs. 8.1) and fecal (6.1 vs. 6.0) pH were unaffected (P>0.30). In conclusion, data suggest that in a competitive farm housing and eating environment, offering high-producing cows CF vs. TMR did increase milk fat, protein and energy production without affecting feed intake and eating and chewing behaviors. Findings will have significant economical and health implications for global dairy enterprises.
Keywords: Total mixed ration, Component feeding, Dairy cow, Milk production