Browsing by Subject "feed efficiency"

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    Comparison of ProCROSS and Holstein cows for dry matter intake, body weight, cow height, body condition score, production, feed efficiency, income over feed cost, and residual feed intake
    (2018-06) Shonka-Martin, Brittany
    ProCROSS (Montbéliarde, Viking Red, Holstein) rotational crossbred cows were compared to Holstein (HO) cows for dry matter intake (DMI), body weight (BW), cow height, body condition score (BCS), production, alternative measures of feed efficiency, income over feed costs (IOFC), and residual feed intake (RFI) from 4 to 150 days in milk (DIM) of first, second, and third lactations. Primiparous and multiparous ProCROSS (n = 63 and n = 43, respectively) and HO (n = 60 and n = 37, respectively) cows calved from September 2014 to June 2017. Cows were fed the same total mixed ration twice daily with refusals weighed once daily, and feed was analyzed for dry matter content, net energy of lactation, and crude protein content. The BW was recorded twice weekly, and height at the withers and the hips was recorded monthly. The BCS was evaluated weekly. Daily production of milk, fat, and protein were estimated from monthly test days using Best Prediction. Measures of efficiency from 4 to 150 DIM were feed conversion efficiency (FCE), defined as fat plus protein production (kg) per kilogram of DMI; ECM/DMI, defined as kilograms of energy-corrected milk (ECM) per kilogram of DMI; net energy of lactation efficiency (NELE), defined as ECM (kg) per megacalorie of net energy of lactation intake; crude protein efficiency (CPE), defined as true protein production (kg) per kilogram of crude protein intake; and DMI/BW, defined as DMI (kg) per kilogram of BW. The IOFC was defined as revenue from fat plus protein production minus feed cost. The RFI from 4 to 150 DIM for each lactation was the residual error remaining from regression of DMI on milk energy output (Mcal), metabolic BW (BW0.75), and change in body energy (Mcal). Primiparous and multiparous cows were analyzed separately. Statistical analysis for primiparous cows included the fixed effects of year of calving and breed group, and the analysis for multiparous cows included the fixed effect of breed group and the repeated effect of cow nested within breed group. Primiparous ProCROSS cows (2,807 kg) had lower mean DMI than HO (2,948 kg) cows from 4 to 150 DIM of first lactation. Mean BW was not different for the ProCROSS (562 kg) and HO (556 kg) cows, but primiparous ProCROSS cows had mean wither height that was 4.0 cm shorter and mean hip height that was 2.0 cm shorter than the means of HO cows. Primiparous ProCROSS (3.46) had higher mean BCS compared to HO cows (3.20). Mean fat plus protein production did not differ for the primiparous ProCROSS and HO cows (331 kg vs. 329 kg, respectively). Primiparous ProCROSS cows had higher means for FCE (+5.5%), ECM/DMI (+4.0%), NELE (+4%), and CPE (+5.2%), but a lower mean DMI/BW (–5.3%), than primiparous HO cows. Primiparous ProCROSS cows ($875) also had higher mean IOFC than primiparous HO cows ($825). In addition, mean RFI from 4 to 150 DIM was significantly lower (more desirable) for primiparous ProCROSS cows than HO cows. Multiparous ProCROSS cows (3,360 kg) also had lower mean DMI than HO cows (3,592 kg) and did not differ (636 kg) from HO cows (644 kg) for mean BW. The ProCROSS cows had mean wither height that was 3.5 cm shorter than HO cows, but mean hip height did not differ for multiparous ProCROSS (145.2 cm) and HO cows (146.4 cm). Mean BCS was higher for multiparous ProCROSS cows (3.25) than for HO cows (3.06), and mean fat plus protein production was not different for multiparous ProCROSS (445 kg) and HO (441 kg) cows. The multiparous ProCROSS cows had higher means for FCE (+8.2%), ECM/DMI (+5.9%), NELE (+5.8%), and CPE (+8.1%) and a lower mean for DMI/BW (–4.8%) than multiparous HO cows. Multiparous ProCROSS cows ($1,296) also had a higher mean for IOFC than multiparous HO cows ($1,208) and a lower mean for RFI from 4 to 150 DIM than HO cows.