## 5 The Establishment of Integrated Beef and Dairy Systems  
While the history of cattle domestication is poorly documented, it occurred more than 10,000 years ago [50], there is evidence that milk was in use by the seventh millennium BC [51] in the Near East and southeastern Europe, and while the fate of male progeny from that time is uncertain, it seems likely that they would have been kept for mating and/or meat production in what originally would almost certainly have been a mixed production system. Accordingly, there is nothing new in using the unwanted, typically male progeny of dairy cows for meat production. In one review, it was explained how the desire to increase profit on dairy farms necessitates consideration of the revenue attainable from the sale of surplus calves for meat production, but noting that the generation of calves with improved growth and carcass merit must not be achieved at the expense of the dairy dam and her ability to calve and re-establish pregnancy early after calving without any compromise to her milk production value [47]. In a separate review, it was also surmised that interest in the generation of more valuable calves for meat production from dairy females is intensifying, and that the most likely vehicle is the use of appropriately selected beef bulls for mating with the dairy females [52]. \begin{table}
\begin{tabular}{l c c c} \hline \hline
**Breed** & **MSTN Mutation** & **Effect** \\ \hline Belgium Blue & c.821(del11) & Double-muscled phenotype, high tenderness \\ Angus & c.821(del11) & Increased EMA, reduced fatness \\ Angus-cross & c.821(del11) & Higher carcass weights, no effect on marbling \\ Senepol & c.821(del11) & Larger _Longssimus dors_ muscle, leaner carcasses \\ Limousin & c.282A & 5.5\% increase in silverside percentage and EMA, \\  & & & 2.3\% increase in total meat percentage \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Effects of the _MSTN_ c.821(del11) in different breeds. \begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Bull Breed** & **No** &
\begin{tabular}{c} **Calving Difficulty** \\ **(eBV) * ** & **Calving Difficulty** \\ **(Relative)** & **Difficulty Range** & **Length (eBV)** & **Length (Relative)** \\ \hline Belgian & & & & & \\ Blue-_MSTN_ & 50 & 1.09 & 44 & (\(-\)1.0 to +7.4) & \(-\)0.4 & 97 \\ nt821(del11) & & & & & & \\ \hline Angus & 127 & 0.29 & 32 & (\(-\)2.2 to +7.1) & \(-\)2.6 & 94 \\ Current Friesians & 6795 & 1.30 & 64 & (\(-\)4.0 to +10.6) & \(-\)0.6 & 97 \\ \hline Suitable Angus & 81 & \(-\)0.29 & 32 & (\(-\)2.2 to +0.4) & \(-\)3.0 & 94 \\ \hline Suitable Belgian & & & & & \\ Blue-_MSTN_ & 19 & \(-\)0.10 & 47 & (\(-\)1.0 to +0.4) & \(-\)1.2 & 96 \\ nt821(del11) & & & & & & \\ \hline Crossbred & 1700 & \(-\)0.27 & 67 & (\(-\)5.0 to +3.9) & \(-\)2.4 & 97 \\ \hline Total & 8772 & 0.42 & 38 & (\(-\)4.0 to +7.4) & 2.2 & 95 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Beef site calving ease and gestation length from New Zealand Animal Evaluation Limited (NZAEL; Hamilton, New Zealand) dairy database *. It was suggested that one of the biggest challenges in achieving the aim of obtaining better meat production from dairy systems is to balance the often antagonistic and heritable traits associated with calving performance and carcass merit [47]. One tool to do this would be to create selection indices that include estimates of breeding value for both calving ease and meat production traits. The authors suggested this might include selection for direct calving difficulty, gestation length; calf mortality, feed intake, carcass merit (including weight, conformation, and fat), docility, and whether the calf was polled. In an analysis of 3835 bulls from 14 breeds used to artificially inseminate dairy cows, the study reported that superior carcass and growth performance can be achieved with the appropriate selection of beef bulls for use on dairy females, and with only a modest increase in the negative effect on cow performance (i.e., 2-3% greater dystcia expected and a 6-day-longer gestation length).