Please note that Mommsen uses the AUC chronology (Ab Urbe Condita), i.e. from the founding of the City of Rome. You can use this reference table to have the B.C. dates
From: The History of Rome, by Theodor Mommsen
Translated with the sanction of the author by William Purdie Dickson
Pastoral husbandry was prosecuted on a great scale far more than agriculture. An estate in pasture land (-saltus-) had of necessity in every case an area considerably greater than an arable estate--the least allowance was 800 -jugera- --and it might with advantage to the business be almost indefinitely extended. Italy is so situated in respect of climate that the summer pasture in the mountains and the winter pasture in the plains supplement each other: already at that period, just as at the present day, and for the most part probably along the same paths, the flocks and herds were driven in spring from Apulia to Samnium, and in autumn back again from Samnium to Apulia. The winter pasturage, however, as has been already observed, did not take place entirely on ground kept for the purpose, but was partly the grazing of the stubbles.
Horses, oxen, asses, and mules were reared, chiefly to supply the animals required by the landowners, carriers, soldiers, and so forth; herds of swine and of goats also were not neglected. But the almost universal habit of wearing woollen stuffs gave a far greater independence and far higher development to the breeding of sheep. The management was in the hands of slaves, and was on the whole similar to the management of the arable estate, the cattle-master (-magister pecoris-) coming in room of the steward. Throughout the summer the shepherd-slaves lived for the most part not under a roof, but, often miles remote from human habitations, under sheds and sheepfolds; it was necessary therefore that the strongest men should be selected for this employment, that they should be provided with horses and arms, and that they should be allowed far greater freedom of movement than was granted to the slaves on arable estates.
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Reference address : https://www.ellopos.net/elpenor/rome/3-12-management-land-capital.asp?pg=14