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Dairy cattle crossbreeding and milk production

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Dairy cattle crossbreedingand milk production.The aim of this study was to compare the results of milk performance of purebred Polish Holstein-Frisian (PHF) cows and their crossbreeds (PHF x SRB). Data for the analysis originated from the Polish Federation of Dairy Cattle Breeder and Producers - cows reports. The results indicate a positive influence of the breed on milk composition: fat, protein and dry matter content and somatic cell count. purebred Polish Holstein-Frisian (PHF) cows had significantly higher (p≤0.05) milk yield for both the 100 and 305 days milking. The milk production of MM cows is lower by 15.89%, at 100 days of lactation, and by 34.57% in the full lactation than PHF.
The objective of the study was to determine beef production traits of dairy and dairy × beef breed crossbred heifers. The data from Finnish slaughterhouses included observations of 14 221 Nordic Red (NR), 6 348 Holstein-Friesian (Hol), 1 626 NR × Aberdeen Angus (NR × Ab), 1 136 NR × Blonde d’Aquitaine (NR × Ba), 802 NR × Charolais (NR × Ch), 487 NR × Hereford (NR × Hf), 3 699 NR × Limousin (NR × Li), 827 NR × Simmental (NR × Si), 531 Hol × Ab, 467 Hol × Ba, 438 Hol × Ch, 186 Hol × Hf, 1 249 Hol × Li and 393 Hol × Si heifers. Crossbreeding with late maturing beef breeds (Ba, Ch, Li, Si) had favourable effects both on daily carcass gain and carcass quality traits (conformation, proportion of high value joints) of the progeny when compared to purebred dairy heifers. No advantages in proportion of high value joints seemed to be obtained by crossbreeding dairy cows with Ab or Hf breeds, while the improvements in daily carcass gain and carcass conformation score were intermediate compared to the late maturing crossbreds.
Fattening performance and carcass compositions were compared between Akkaraman (A), Kývýrcýk x Akkaraman F2 (KAF2 ), Kývýrcýk x (Kývýrcýk x Akkaraman) first backcross (KAB1 ), Chios x Akkaraman F2 (CAF2 ) and Chios x (Chios x Akkaraman) fist backcross (CAB1 ) ram lambs. After weaning at 3 months of age, the lambs were fed ad libitum concentrate and 300 g of alfalfa hay per lamb, per day. Six lambs of each genotype were slaughtered at 45 kg live weight and the carcasses were evaluated. The average daily weight gain and feed conversion efficiencies were 284, 271, 279, 282, 274 g and 4.92, 4.81, 4.76, 4.89, 5.01 for A, KAF2 , KAB1 , CAF2 and CAB1 , respectively. Corresponding values for cold dressing percentages were 49.28, 48.89, 48.18, 49.15 and 46.79, respectively. The weight of various fat depots differed (P<0.001 or P<0.01) among genotypes, but the weight of major cuts as a percentage of carcass weight did not differ significantly among genotypes except for percentage loin (P<0.05). It was concluded that there were no statistically significant differences for fattening performance among genotypes and that KA crossbred lambs had a higher percentage of loin and a lower percentage of bone in some of the major cuts. Also, there was a tendency for genotypes with lower tail fat weight to have a higher depot fat.
Levels of Cortisol in blood serum of 50- and 100-day-old rams of Kamieniecka sheep (K) and its crossbreds (F,) with Berrichon du Cher (KxBCH) and Blackhead (K x B) rams before pre-slaughter handling and after slaughter were determined. No relationship between the Cortisol levels and the genotype of the animals were found. However, age-dependent differences in the concentrations of the hormone (P ≤ 0.01) were disclosed. In the group of 50-day-old rams, the level of Cortisol was 48.69 nmol/1 whereas in older animals it was 61.53 nmol/1. After handling and slaughter a significant increase in the hormone levels from 39.51 to 70.72 nmol/1 was found, presumably reflecting a pronounced stress response of the animal organisms.
The aim of this study was to investigate the effects of crossbreeding indigenous Hair Goat with Saanen on carcass quality characteristics of kids under an intensive production system. Twenty four male kids from purebred Hair Goat and Saanen × Hair Goat (F1 and B1) crossbred genotypes were weaned at 75-80 days of age and fattened for 56 days. Slaughter weights were 17.42, 18.22 and 16.79 kg and chilled carcass weights were 6.49, 7.29 and 6.69 kg for Hair Goat, F1 and B1, respectively. The organ weights, dressing percentages, M. longissimus dorsi area, fatness parameters, carcass measurements, subcutaneous fat colour, carcass joint weights and percentages and dissected leg compositions of kids were similar (P>0.05) in genotype groups. It is concluded that crossbreeding indigenous Hair Goat with Saanen at F1 and B1 levels did not result in any improvement in quality carcass production of kids under an intensive production system.
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