A mower conditioner capable of severing standing crop material from the ground and conditioning the crop material as it is passed rearwardly through mower conditioner, the mower conditioner comprising: a crop cutting assembly that severs crop material from the ground as the mower conditioner is pulled across a field; a lift mechanism configured to raise and lower the crop cutting assembly to a desired height comprising at least one lift cylinder and a hydraulic lift circuit supplying hydraulic fluid to the at least one lift cylinder; a conditioning mechanism receiving the severed crop material from the crop cutting assembly, the conditioning mechanism comprising: a pair of counter-rotating conditioning rolls (30,32) to condition the crop material; a tensioning assembly that urges the conditioning rolls (30,32) relatively toward one another and resists their separation, the tensioning assembly comprising: a pair of hydraulic tension cylinders (52,54) located at opposite ends of one of the pair of conditioning rolls (30,32); and a hydraulic conditioner circuit configured to supply hydraulic fluid to the tension cylinders (52,54), the hydraulic tension circuit comprising a supply line leading to a supply valve, the mower conditioner being characterised in that i) the mower conditioner is a pull-type mower conditioner configured to be pulled across a field by a towing vehicle; and ii) the supply line taps into the lift circuit so that opening the supply valve allows transfer of hydraulic fluid between the lift circuit and the conditioner circuit. a crop cutting assembly that severs crop material from the ground as the mower conditioner is pulled across a field; a lift mechanism configured to raise and lower the crop cutting assembly to a desired height comprising at least one lift cylinder and a hydraulic lift circuit supplying hydraulic fluid to the at least one lift cylinder; a conditioning mechanism receiving the severed crop material from the crop cutting assembly, the conditioning mechanism comprising: a pair of counter-rotating conditioning rolls (30,32) to condition the crop material; a tensioning assembly that urges the conditioning rolls (30,32) relatively toward one another and resists their separation, the tensioning assembly comprising: a pair of hydraulic tension cylinders (52,54) located at opposite ends of one of the pair of conditioning rolls (30,32); and a hydraulic conditioner circuit configured to supply hydraulic fluid to the tension cylinders (52,54), the hydraulic tension circuit comprising a supply line leading to a supply valve, the mower conditioner being characterised in that i) the mower conditioner is a pull-type mower conditioner configured to be pulled across a field by a towing vehicle; and ii) the supply line taps into the lift circuit so that opening the supply valve allows transfer of hydraulic fluid between the lift circuit and the conditioner circuit. a pair of counter-rotating conditioning rolls (30,32) to condition the crop material; a tensioning assembly that urges the conditioning rolls (30,32) relatively toward one another and resists their separation, the tensioning assembly comprising: a pair of hydraulic tension cylinders (52,54) located at opposite ends of one of the pair of conditioning rolls (30,32); and a hydraulic conditioner circuit configured to supply hydraulic fluid to the tension cylinders (52,54), the hydraulic tension circuit comprising a supply line leading to a supply valve, the mower conditioner being characterised in that i) the mower conditioner is a pull-type mower conditioner configured to be pulled across a field by a towing vehicle; and ii) the supply line taps into the lift circuit so that opening the supply valve allows transfer of hydraulic fluid between the lift circuit and the conditioner circuit. a pair of hydraulic tension cylinders (52,54) located at opposite ends of one of the pair of conditioning rolls (30,32); and a hydraulic conditioner circuit configured to supply hydraulic fluid to the tension cylinders (52,54), the hydraulic tension circuit comprising a supply line leading to a supply valve, the mower conditioner being characterised in that i) the mower conditioner is a pull-type mower conditioner configured to be pulled across a field by a towing vehicle; and ii) the supply line taps into the lift circuit so that opening the supply valve allows transfer of hydraulic fluid between the lift circuit and the conditioner circuit. i) the mower conditioner is a pull-type mower conditioner configured to be pulled across a field by a towing vehicle; and ii) the supply line taps into the lift circuit so that opening the supply valve allows transfer of hydraulic fluid between the lift circuit and the conditioner circuit.