Browsing by Subject "crossbreeding"

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    Alternative Feeding Practices for Dairy Calves and Beta-Casein Genotype and Its Effect on Dairy Cows
    (2022-12) Arens, Sara
    These studies were conducted to compare how different genotypes and breed groups affect dairy calf and cow management. Specific focus was put on alternative management practices or niche markets that dairy producers face today. The objective of the first study was to compare crossbred dairy calves to Holstein calves for growth and milk consumption behaviors while being fed alternative milk allowances in an automated group feeding system. Calves fed ad libitum milk exhibited an increased growth rate and weaning weight without compromising the health of the calves, compared to calves fed 8 L. Breed groups exhibited no difference in weaning weight or health scores. Limousin crossbred calves exhibited a lower milk consumption, but increased growth rate compared to the other breed groups. The results of this study indicate feeding dairy calves ad libitum may increase milk cost but could be economically advantageous if increased growth rates are also realized. The objective of the second study was to compare the beta-casein genotype impact on production, fertility, and survival amongst purebred certified-organic Holstein cows. Herd had an effect on the production, fertility, and survival of the cows. Parity effected times bred, days open, and all production traits. The beta-casein genotype of the cows and the herd affected the percentage of cows that survived to the start of the subsequent lactation. This study indicated beta-casein genotype had no effect on the fertility and production of organic dairy herds. Meanwhile, survival may be biased against the A1A1 genotype as shown by lower survival rates to each lactation. This study may offer organic producers more flexibility in breeding programs and culling decisions to produce A2 milk. The results of both studies offer producers more insight into new management strategies to achieve their on-farm goals without compromising genetic or monetary input.
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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.
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    Lactation Curves of Montbeliarde-Sired and Viking Red-Sired Crossbred Cows and Their Holstein Herdmates in 7 Commercial Dairies Using Random Regression and Best Prediction
    (2019-12) Houdek, Eric
    Lactation curves were estimated for Montbéliarde (MO) × Holstein (HO) and Viking Red (VR) × HO 2-breed crossbred cows and for MO × VR/HO and VR × MO/HO 3-breed crossbred cows and their HO herdmates from test-day observations in 7 high-performance dairies that participated in a designed research study. Cows calved from 2010 to 2017. Test-day observations from milk recording for the first 3 lactations were used to fit the lactation curves. Lactations of cows were required to have at least 250 days in milk (DIM) and to have at least 6 test days ≤ 265 DIM. Lactation curves from random regression (RR) functions were compared: 1) Ali-Schaeffer, 2) Wilmink, and 3) Third-order Legendre polynomial. Lactation curves from RR were also compared to lactation curves from Best Prediction (BP). The alternative RR functions and BP were compared for the lactation curve characteristics of 305-d production (kg), peak production (kg), peak d of production, and production from 4 to 103 DIM (kg), from 104 to 205 DIM (kg), and from 206 to 305 DIM (kg) for milk, fat, and protein production. Primiparous and multiparous cows were analyzed separately. Furthermore, two alternative measures of persistency of production were developed for each of the alternative RR functions and BP. The 2-breed and 3-breed crossbred cows and their respective HO herdmates were analyzed separately. For primiparous cows, Legendre polynomial RR best fit the actual test-day observations for milk, fat, and protein production among the alternative RR functions as well as BP for each breed group separately and across breed groups for both 2-breed and 3-breed crossbreds and their HO herdmates. For multiparous cows, BP best fit the actual test-day observations for milk and fat production for each breed group separately and across breed groups for both 2-breed and 3-breed crossbreds. However, Legendre polynomial RR best fit the actual test-day observations for protein production in all cases.